Evaluation of the toxicity of secondary metabolites in Solanum incanum L. to advance community knowledge
- Authors: Zivanayi, William
- Date: 2023-04
- Subjects: Solanum -- Zimbabwe , Pesticides -- Toxicology , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61018 , vital:69686
- Description: The effects of pests and the need to produce adequate food have influenced small-scale farmers in disadvantaged communities to adopt and utilise natural plant pesticides to improve harvests in many Southern African Development Communities. However, the phytochemistry associated with these indigenous plants’ pesticide activity still needs to be explored. The lack of evidence of scientific knowledge of the plant species has caused a lot of health issues among the users of indigenous plant pesticides. Solanum incanum is among the plants utilised to control cabbage aphids in Mkoba village, Zimbabwe. Solanum species are known for their steroidal compounds which comprise glycoalkaloids and saponins. This study evaluated the knowledge, opinions, and attitudes of the vegetable peasant farming community in Gweru regarding their use of the indigenous plant (S. incanum) as a pesticide. The study also reported the phytochemical profiling, structural characterisation of the isolated compounds, and biological and pesticidal activity evaluation of phytochemicals isolated from S. incanum. A descriptive survey was carried out to assess the knowledge, attitude, and practices of a conveniently sampled group of vegetable farmers in Mkoba village who use S. incanum as a pesticide. Forty-nine respondents comprised of 19 males and 30 females of ages ranging from 15 to above 60 years took part in the study by answering an open and closed-ended questionnaire. The survey revealed that parents and neighbours were instrumental in disseminating pesticidal information in the community. Brassica napus were the most grown.vegetable and vulnerable to cabbage aphids. Mixed opinions amongst the respondents varied regarding the health and environmental impact of S. incanum as a pesticide. Seventy-five percent (75%) of the respondents supported the use of S. incanum as a pesticide whilst 25% claimed that the use of S. incanum was the source of the health problems experienced in the community. The survey demonstrated that (45)91% of the farmers displayed poor practices regarding the disposal of empty pesticide containers and the use of personal protective clothing. The most prevalent symptoms in the community were skin rash, nausea, headache, and poor vision and these symptoms were common in the age group 30 to 60 years. , Thesis (PhD) -- Faculty of Science, School of biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Zivanayi, William
- Date: 2023-04
- Subjects: Solanum -- Zimbabwe , Pesticides -- Toxicology , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61018 , vital:69686
- Description: The effects of pests and the need to produce adequate food have influenced small-scale farmers in disadvantaged communities to adopt and utilise natural plant pesticides to improve harvests in many Southern African Development Communities. However, the phytochemistry associated with these indigenous plants’ pesticide activity still needs to be explored. The lack of evidence of scientific knowledge of the plant species has caused a lot of health issues among the users of indigenous plant pesticides. Solanum incanum is among the plants utilised to control cabbage aphids in Mkoba village, Zimbabwe. Solanum species are known for their steroidal compounds which comprise glycoalkaloids and saponins. This study evaluated the knowledge, opinions, and attitudes of the vegetable peasant farming community in Gweru regarding their use of the indigenous plant (S. incanum) as a pesticide. The study also reported the phytochemical profiling, structural characterisation of the isolated compounds, and biological and pesticidal activity evaluation of phytochemicals isolated from S. incanum. A descriptive survey was carried out to assess the knowledge, attitude, and practices of a conveniently sampled group of vegetable farmers in Mkoba village who use S. incanum as a pesticide. Forty-nine respondents comprised of 19 males and 30 females of ages ranging from 15 to above 60 years took part in the study by answering an open and closed-ended questionnaire. The survey revealed that parents and neighbours were instrumental in disseminating pesticidal information in the community. Brassica napus were the most grown.vegetable and vulnerable to cabbage aphids. Mixed opinions amongst the respondents varied regarding the health and environmental impact of S. incanum as a pesticide. Seventy-five percent (75%) of the respondents supported the use of S. incanum as a pesticide whilst 25% claimed that the use of S. incanum was the source of the health problems experienced in the community. The survey demonstrated that (45)91% of the farmers displayed poor practices regarding the disposal of empty pesticide containers and the use of personal protective clothing. The most prevalent symptoms in the community were skin rash, nausea, headache, and poor vision and these symptoms were common in the age group 30 to 60 years. , Thesis (PhD) -- Faculty of Science, School of biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-04
Chang liver cell line as a model for Type II Diabetes in the liver and possible reversal of this condition by an indigenous medicinal plant
- Authors: Williams, Saralene Iona
- Date: 2009
- Subjects: Diabetes -- Alternative treatment , Medicinal plants , Traditional medicine , Liver -- Diseases
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10339 , http://hdl.handle.net/10948/d1016179
- Description: The incidence of Type 2 Diabetes Mellittus (T2DM) is increasing world wide. In Africa the limited access to health care and the insidious course of the disease lead to more severe illness and diabetic complications. There is a need to find alternative approaches to treatment and prevention that address the problems and needs of Africa. Sutherlandia frutescens (S.frutescens) is a traditional herbal plant with known anti-diabetic properties, the precise mechanism of action of S.frutescens is not known. In order to develop new approaches for treatment and prevention of T2DM the pathophysiology of T2DM must be understood. T2DM is the final outcome of a multi-organ disease characterized by early defects in muscle, adipocytes, hepatocytes and pancreatic β-cells. In this study the role of the liver was investigated because of its central role in glucose and lipid metabolism. It is hard to differentiate between all the influences in an in vivo model, so the aim of this study was to develop an in vitro model of T2DM in Chang liver cells and to determine if S.frutescens can reverse the state of insulin resistance in this model. Different culture media conditions were screened to identify a method that can be used as the T2DM model in Chang liver cells. Serum free medium (MCBD-201) supplemented with human diabetic serum, (2.5%-10%), high insulin concentrations (0.1μM-1μM), high fructose concentrations (1-10mM). and a combination of high insulin and high fructose was used for this screening. Chang liver cells cultured in MCBD-201 medium supplemented with 1mM fructose and 0.1μM insulin showed reduced glucose uptake and increased lipid accumulation. The effect of two S.frutescens extracts, two anti-diabetic drugs, metformin and ciglitazone, and a hypolipidemic drug ciprofibrate were determined and shown to increase glucose uptake and reduce lipid accumulation. It was postulated that exposing the cells to excess nutrients in the form of high fructose would stimulate the cells to become adipogenic and accumulate lipids, which would interfere with the glucose uptake and induce insulin resistance. Gene expression of PPARγ, PPARα, and SREBP-1 transcription factors regulating lipid metabolism was determined in Chang liver cells cultured in insulin resistance inducing medium over a 48 hour time course. The expression of PPARγ, known to stimulate adipogenesis was increased after 6, 24 and 48 hours of exposure (P(H1)<0.0001). The expression of PPARα, known to stimulate β-oxidation expression, was significantly decreased after 24 hours of exposure (P(H1)<0.0001). The presence of the plant extracts in the insulin resistance inducing media protect against this increase in adipogenesis and decrease in β-oxidation after 48 hours of exposure by increasing PPARα expression and decreasing PPARγ expression. A PCR Array was performed which identified 32 more potential molecular targets of S.frutescens. Five of the 32 targets identified with the PCR Array were validated using qRT-PCR. These genes play a role in lipid and glucose metabolism and protection against oxidative stress and inflammation. In summary a cellular model of insulin resistace in hepatocytes has been established and the capacity of S.frutescens to reverse this process has been demonstrated by acting as a dual PPARγ/α agonist. New genes have been identified in the development of insulin resistance and as targets of S.frutescens.
- Full Text:
- Date Issued: 2009
- Authors: Williams, Saralene Iona
- Date: 2009
- Subjects: Diabetes -- Alternative treatment , Medicinal plants , Traditional medicine , Liver -- Diseases
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10339 , http://hdl.handle.net/10948/d1016179
- Description: The incidence of Type 2 Diabetes Mellittus (T2DM) is increasing world wide. In Africa the limited access to health care and the insidious course of the disease lead to more severe illness and diabetic complications. There is a need to find alternative approaches to treatment and prevention that address the problems and needs of Africa. Sutherlandia frutescens (S.frutescens) is a traditional herbal plant with known anti-diabetic properties, the precise mechanism of action of S.frutescens is not known. In order to develop new approaches for treatment and prevention of T2DM the pathophysiology of T2DM must be understood. T2DM is the final outcome of a multi-organ disease characterized by early defects in muscle, adipocytes, hepatocytes and pancreatic β-cells. In this study the role of the liver was investigated because of its central role in glucose and lipid metabolism. It is hard to differentiate between all the influences in an in vivo model, so the aim of this study was to develop an in vitro model of T2DM in Chang liver cells and to determine if S.frutescens can reverse the state of insulin resistance in this model. Different culture media conditions were screened to identify a method that can be used as the T2DM model in Chang liver cells. Serum free medium (MCBD-201) supplemented with human diabetic serum, (2.5%-10%), high insulin concentrations (0.1μM-1μM), high fructose concentrations (1-10mM). and a combination of high insulin and high fructose was used for this screening. Chang liver cells cultured in MCBD-201 medium supplemented with 1mM fructose and 0.1μM insulin showed reduced glucose uptake and increased lipid accumulation. The effect of two S.frutescens extracts, two anti-diabetic drugs, metformin and ciglitazone, and a hypolipidemic drug ciprofibrate were determined and shown to increase glucose uptake and reduce lipid accumulation. It was postulated that exposing the cells to excess nutrients in the form of high fructose would stimulate the cells to become adipogenic and accumulate lipids, which would interfere with the glucose uptake and induce insulin resistance. Gene expression of PPARγ, PPARα, and SREBP-1 transcription factors regulating lipid metabolism was determined in Chang liver cells cultured in insulin resistance inducing medium over a 48 hour time course. The expression of PPARγ, known to stimulate adipogenesis was increased after 6, 24 and 48 hours of exposure (P(H1)<0.0001). The expression of PPARα, known to stimulate β-oxidation expression, was significantly decreased after 24 hours of exposure (P(H1)<0.0001). The presence of the plant extracts in the insulin resistance inducing media protect against this increase in adipogenesis and decrease in β-oxidation after 48 hours of exposure by increasing PPARα expression and decreasing PPARγ expression. A PCR Array was performed which identified 32 more potential molecular targets of S.frutescens. Five of the 32 targets identified with the PCR Array were validated using qRT-PCR. These genes play a role in lipid and glucose metabolism and protection against oxidative stress and inflammation. In summary a cellular model of insulin resistace in hepatocytes has been established and the capacity of S.frutescens to reverse this process has been demonstrated by acting as a dual PPARγ/α agonist. New genes have been identified in the development of insulin resistance and as targets of S.frutescens.
- Full Text:
- Date Issued: 2009
The effect of in vitro digestion on selected biological activities of Hypoxis sobolifera corms
- Authors: Van Rooyen, Anzel
- Date: 2013
- Subjects: Potatoes -- Therapeutic use , Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10344 , http://hdl.handle.net/10948/d1020058
- Description: In South Africa part of the cultural and religious beliefs of the African people is the use of traditional remedies to treat diseases. These remedies are obtained from medicinal plants (Steenkamp, 2003). One of the most frequently traded plants in the Eastern Cape is Hypoxis, commonly known as Afrika patat, or African potato. South African traditional healers instruct patients to brew the fresh Hypoxis corm as a tea and then ingest it (Steenkamp, 2006a). This prompted an investigation into the digestive stability of a traditionally prepared Hypoxis extract. The H. sobolifera extracts were digested using a simulated gastric/small intestinal digestion and their biological activity determined. The hot water H. sobolifera extract before digestion only showed cytotoxic activity against cancer cell lines at very high concentrations which are not likely to be achieved under normal ingestion circumstances. In Chang liver cells on the other hand, chronic exposure to the hot water H. sobolifera extract increased glucose uptake in amounts similar to that of metformin. On the negative side, the glucose utilization stimulation was lost due to the simulated digestion process. The significant inhibition of AGEs by hot water H. sobolifera extract (IC50 of 6.3 Ig/ml) is a very encouraging result as treatment in the management of diabetes. This activity was only slightly reduced by the in vitro digestion process. Also observed was enzyme inhibition activity by traditionally prepared H. sobolifera, with ∝-amylase being inhibited (IC50 of approximately 250 Ig/ml) and therefore preventing or limiting starch breakdown. From the DPPH results it was clear that H. sobolifera, even when digested, is a potent anti-oxidant (IC50 of 134.4 Ig/ml when undigested compared to 162.9 when digested with β-glucosidase added to stomach digestive step). HPLC and TLC experiments revealed that rooperol which has previously been thought to be the compound responsible for the anti-oxidant activity in Hypoxis extracts, was absent from the traditional extract of H. sobolifera and therefore cannot be the sole compound exhibiting anti-oxidant activity; other compounds such as phenolics may be contributing. The phenolic and flavonoid content results revealed very highconcentrations of these compounds in the traditionally prepared H. sobolifera extract. These compounds may therefore play major roles in all of the biological activities observed from treatment with Hypoxis spp. The ROS results yielded interesting and promising results. Using standard or traditionally prepared H. sobolifera extracts, activation of differentiated U937 cells with PMA was greatly enhanced by cotreatment with the extracts, while extracts on their own did not cause significant activation. Future studies should investigate this property of the extracts as a promising immune boosterThe HPLC results showed that hypoxoside was undetectable in the hot water traditional extract and the TLC anti-oxidant experiment proved that rooperol is not present in the hot water traditional extract after treatment with β-glucosidase. This indicates that neither one of the Hypoxis compounds previously believed to be responsible for the biological activities observed are present in the extract when prepared the traditional way. Therefore, the biological activities observed in this study can be attributed to other phytochemical compounds.
- Full Text:
- Date Issued: 2013
- Authors: Van Rooyen, Anzel
- Date: 2013
- Subjects: Potatoes -- Therapeutic use , Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10344 , http://hdl.handle.net/10948/d1020058
- Description: In South Africa part of the cultural and religious beliefs of the African people is the use of traditional remedies to treat diseases. These remedies are obtained from medicinal plants (Steenkamp, 2003). One of the most frequently traded plants in the Eastern Cape is Hypoxis, commonly known as Afrika patat, or African potato. South African traditional healers instruct patients to brew the fresh Hypoxis corm as a tea and then ingest it (Steenkamp, 2006a). This prompted an investigation into the digestive stability of a traditionally prepared Hypoxis extract. The H. sobolifera extracts were digested using a simulated gastric/small intestinal digestion and their biological activity determined. The hot water H. sobolifera extract before digestion only showed cytotoxic activity against cancer cell lines at very high concentrations which are not likely to be achieved under normal ingestion circumstances. In Chang liver cells on the other hand, chronic exposure to the hot water H. sobolifera extract increased glucose uptake in amounts similar to that of metformin. On the negative side, the glucose utilization stimulation was lost due to the simulated digestion process. The significant inhibition of AGEs by hot water H. sobolifera extract (IC50 of 6.3 Ig/ml) is a very encouraging result as treatment in the management of diabetes. This activity was only slightly reduced by the in vitro digestion process. Also observed was enzyme inhibition activity by traditionally prepared H. sobolifera, with ∝-amylase being inhibited (IC50 of approximately 250 Ig/ml) and therefore preventing or limiting starch breakdown. From the DPPH results it was clear that H. sobolifera, even when digested, is a potent anti-oxidant (IC50 of 134.4 Ig/ml when undigested compared to 162.9 when digested with β-glucosidase added to stomach digestive step). HPLC and TLC experiments revealed that rooperol which has previously been thought to be the compound responsible for the anti-oxidant activity in Hypoxis extracts, was absent from the traditional extract of H. sobolifera and therefore cannot be the sole compound exhibiting anti-oxidant activity; other compounds such as phenolics may be contributing. The phenolic and flavonoid content results revealed very highconcentrations of these compounds in the traditionally prepared H. sobolifera extract. These compounds may therefore play major roles in all of the biological activities observed from treatment with Hypoxis spp. The ROS results yielded interesting and promising results. Using standard or traditionally prepared H. sobolifera extracts, activation of differentiated U937 cells with PMA was greatly enhanced by cotreatment with the extracts, while extracts on their own did not cause significant activation. Future studies should investigate this property of the extracts as a promising immune boosterThe HPLC results showed that hypoxoside was undetectable in the hot water traditional extract and the TLC anti-oxidant experiment proved that rooperol is not present in the hot water traditional extract after treatment with β-glucosidase. This indicates that neither one of the Hypoxis compounds previously believed to be responsible for the biological activities observed are present in the extract when prepared the traditional way. Therefore, the biological activities observed in this study can be attributed to other phytochemical compounds.
- Full Text:
- Date Issued: 2013
Exploring plants as medicine: an in vitro approach
- Authors: Van de Venter, Maryna
- Subjects: Medicinal plants , Oncology , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/55562 , vital:52968
- Description: Introduction: Plants as medicine Archaeological evidence for the use of plants as medicine dates as far back as 60,000 years ago from the area now known as Iraq, and 8,000 years ago from China. The first written records are from the Sumerians from 5,000 BC and the Ancient Egyptians from 1,500 BC. Two well-known plants that were already used in that time are the opium poppy, and cannabis. The first pharmaceutical medicine was only developed in 1804 when the German Friedrich Sertürner isolated morphine from the opium poppy (Pan et al 2014).
- Full Text:
- Authors: Van de Venter, Maryna
- Subjects: Medicinal plants , Oncology , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/55562 , vital:52968
- Description: Introduction: Plants as medicine Archaeological evidence for the use of plants as medicine dates as far back as 60,000 years ago from the area now known as Iraq, and 8,000 years ago from China. The first written records are from the Sumerians from 5,000 BC and the Ancient Egyptians from 1,500 BC. Two well-known plants that were already used in that time are the opium poppy, and cannabis. The first pharmaceutical medicine was only developed in 1804 when the German Friedrich Sertürner isolated morphine from the opium poppy (Pan et al 2014).
- Full Text:
Efficacy of two medical plant extracts and metformin in the prevention of diet induced fatty liver
- Tshidino, Shonisani Cathphonia
- Authors: Tshidino, Shonisani Cathphonia
- Date: 2014
- Subjects: Plant Extracts -- Therapeutic use , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/9066 , vital:26461
- Description: Non‐alcoholic fatty liver diseases (NAFLD) is manifested in the absent of alcohol abuse. This disease is the major cause of liver failure and death among adults and children worldwide, including South Africa. Its increasing prevalence urges the need of therapeutic intervention. The main objectives of this study were to investigate the following: (1) The effect of 38.9% high fat diet (HFD)‐induced insulin resistance and fatty liver in male Wistar rats, (2) The efficacy of aqueous extracts from Sutherlandia frutescens leaves and Prunus africana bark and metformin in the treatment of HFDinduced insulin resistance and fatty liver. Male Wistar rats were fed on HFD (the HF group) or normal rat chow (the LF group) for 12 weeks. Even though the HFD‐fed rats had developed insulin resistance by week 12, fatty liver developed by week 16. After week 12, the HF group was divided into four groups of 6‐7 rats each and three of those groups were gavaged with either 0.125 mg P. africana extract/kg bwt/day (the HF+Pa group) or 50 mg S. frutescens extract kg bwt/day (the HF+Sf group) or 16 mg metformin/ kg bwt/day (HF+Met group), while kept on the same diet for an additional of 4 weeks, to investigate whether two medicinal plant extracts and metformin can prevent HFD to induce fatty liver or not. After 16 weeks, the liver histological images revealed that the HF group developed fatty liver in the form of both microsteatosis and macrosteatosis. Fatty liver was confirmed by significant increased liver total lipid (TL) and activities of glucose‐6‐phosphate dehydrogenase (cG6PD) and xanthine oxidase (XO), mitochondrial NADH oxidase (mNOX) and by a decrease (P<0.05) in the activities of the homogenate superoxide dismutase (hSOD) and mitochondrial complex II in the HF group, when compared to the LF group. Since the activities of mCS and cACL enzymes were not changed in the HF group, hence increased cG6PD activity in the HF group indicates that there was increased NADPH demand for lipid accumulation from activated NEFAs taken up by the liver from circulation and for maintenance of the NADPH‐dependent antioxidants and oxidants, respectively. The obtained data also show that mitochondria of the HFD‐fed rats adapted to an increase in energy availability, thereby compensation through decreasing complex II activity, to allow electron flux from β‐oxidation to respiratory chain in the HF group. Liver TL content was significantly decreased in the rats treated with metformin and P. africana extract, but not in the rats treated with S. frutescens when compared to the HF group (P < 0.05). However, the TL content remained >5% per liver weight in all treated groups. The present study demonstrates that these two plant extracts and metformin have different glucogenic and lipogenic effects from that presented by HFD alone when compared to the LFD alone. In conclusion, metformin and P. africana extract can attenuate HFD‐induced fatty liver without changing the dietary habits. Hence S. frutescens extract is less effective in the prevention of HFD‐induced fatty liver. A change in the dietary habits is recommended to be considered during the use of these three remedies in the treatment of HFD‐induced insulin resistance and fatty liver. All three treatments enhanced antioxidant capacity, and may improve insulin resistance and fatty liver mediated by the present HFD through different mechanism of actions in the liver.
- Full Text:
- Date Issued: 2014
- Authors: Tshidino, Shonisani Cathphonia
- Date: 2014
- Subjects: Plant Extracts -- Therapeutic use , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/9066 , vital:26461
- Description: Non‐alcoholic fatty liver diseases (NAFLD) is manifested in the absent of alcohol abuse. This disease is the major cause of liver failure and death among adults and children worldwide, including South Africa. Its increasing prevalence urges the need of therapeutic intervention. The main objectives of this study were to investigate the following: (1) The effect of 38.9% high fat diet (HFD)‐induced insulin resistance and fatty liver in male Wistar rats, (2) The efficacy of aqueous extracts from Sutherlandia frutescens leaves and Prunus africana bark and metformin in the treatment of HFDinduced insulin resistance and fatty liver. Male Wistar rats were fed on HFD (the HF group) or normal rat chow (the LF group) for 12 weeks. Even though the HFD‐fed rats had developed insulin resistance by week 12, fatty liver developed by week 16. After week 12, the HF group was divided into four groups of 6‐7 rats each and three of those groups were gavaged with either 0.125 mg P. africana extract/kg bwt/day (the HF+Pa group) or 50 mg S. frutescens extract kg bwt/day (the HF+Sf group) or 16 mg metformin/ kg bwt/day (HF+Met group), while kept on the same diet for an additional of 4 weeks, to investigate whether two medicinal plant extracts and metformin can prevent HFD to induce fatty liver or not. After 16 weeks, the liver histological images revealed that the HF group developed fatty liver in the form of both microsteatosis and macrosteatosis. Fatty liver was confirmed by significant increased liver total lipid (TL) and activities of glucose‐6‐phosphate dehydrogenase (cG6PD) and xanthine oxidase (XO), mitochondrial NADH oxidase (mNOX) and by a decrease (P<0.05) in the activities of the homogenate superoxide dismutase (hSOD) and mitochondrial complex II in the HF group, when compared to the LF group. Since the activities of mCS and cACL enzymes were not changed in the HF group, hence increased cG6PD activity in the HF group indicates that there was increased NADPH demand for lipid accumulation from activated NEFAs taken up by the liver from circulation and for maintenance of the NADPH‐dependent antioxidants and oxidants, respectively. The obtained data also show that mitochondria of the HFD‐fed rats adapted to an increase in energy availability, thereby compensation through decreasing complex II activity, to allow electron flux from β‐oxidation to respiratory chain in the HF group. Liver TL content was significantly decreased in the rats treated with metformin and P. africana extract, but not in the rats treated with S. frutescens when compared to the HF group (P < 0.05). However, the TL content remained >5% per liver weight in all treated groups. The present study demonstrates that these two plant extracts and metformin have different glucogenic and lipogenic effects from that presented by HFD alone when compared to the LFD alone. In conclusion, metformin and P. africana extract can attenuate HFD‐induced fatty liver without changing the dietary habits. Hence S. frutescens extract is less effective in the prevention of HFD‐induced fatty liver. A change in the dietary habits is recommended to be considered during the use of these three remedies in the treatment of HFD‐induced insulin resistance and fatty liver. All three treatments enhanced antioxidant capacity, and may improve insulin resistance and fatty liver mediated by the present HFD through different mechanism of actions in the liver.
- Full Text:
- Date Issued: 2014
Assessment of antibacterial potentials of Garcinia Kola seed extracts and their interactions with antibiotics
- Authors: Sibanda, Thulani
- Date: 2007
- Subjects: Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11242 , http://hdl.handle.net/10353/71 , Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants
- Description: The antibacterial potency of the extracts of the seed of Garcinia kola (bitter kola) was investigated in this study against a panel of referenced, environmental and clinical bacterial strains. The killing rates of the active extract as well as their potential for combination antibacterial therapy with standard antibiotics were also elucidated using standard procedures. The aqueous and acetone extracts of the seed were screened for activity against 27 bacterial isolates. The aqueous extract exhibited activity mainly against Gram positive organisms with Minimum inhibitory concentration (MIC) values ranging from 5 mgml-1 – 20 mgml-1, while the acetone extract showed activity against both Gram negative and Gram positive organisms with MIC values ranging from 10 mgml-1 - 0.156 mgml-1. The acetone extract also showed rapid bactericidal activity against Staphylococcus aureus ATCC 6538 with a 3.097 Log10 reduction in counts within 4 hours at 0.3125 mgml-1 and a 1.582 Log10 reduction against Proteus vulgaris CSIR 0030 at 5 mgml-1 after 1 hour. In addition, the aqueous, methanol and acetone extracts of the seeds also exhibited activity against four clinical strains of Staphylococcus isolated from wound sepsis specimens. The MIC values for the aqueous extract were 10 mgml-1 for all the isolates while the acetone and methanol extracts had lower values ranging from 0.3125 - 0.625 mgml-1. The acetone extract was strongly bactericidal against Staphylococcus aureus OKOH3 resulting in a 2.70 Log10 reduction in counts at 1.25 mgml-1 within 4 hours of exposure and a complete elimination of the organism after 8 hours. The bactericidal vi activity of the same extract against Staphylococcus aureus OKOH1 was weak, achieving only a 2.92 Log10 reduction in counts at 1.25 mgml-1 (4× MIC) in 24 hours. In the test for interactions between the acetone extract of the seeds and antibiotics, synergistic interactions were observed largely against Gram positive organisms using the FIC indices, (indices of 0.52 - 0.875) with combinations against Gram negatives yielding largely antagonistic interactions (indices of 2.0 to 5.0). Synergy (≥ 1000 times or ≥ 3 Log10 potentiation of the bactericidal activity) against both Gram negative and Gram positive organisms was detected by time kill assays mainly involving the antibiotics tetracycline, chloramphenicol, amoxycillin and penicillin G. Combinations involving erythromycin and ciprofloxacin consistently gave antagonistic or indifferent interactions. We conclude that the acetone extract of Garcinia kola seeds possess strong bactericidal activities against both Gram positive and Gram negative organisms and can be therapeutically useful in the treatment of bacterial infections including the problematic staphylococcal wound infections. In addition, the acetone extract can be a potential source of broad spectrum resistance modifying compounds that can potentially improve the performance of antibiotics in the treatment of drug resistant infections.
- Full Text:
- Date Issued: 2007
- Authors: Sibanda, Thulani
- Date: 2007
- Subjects: Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11242 , http://hdl.handle.net/10353/71 , Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants
- Description: The antibacterial potency of the extracts of the seed of Garcinia kola (bitter kola) was investigated in this study against a panel of referenced, environmental and clinical bacterial strains. The killing rates of the active extract as well as their potential for combination antibacterial therapy with standard antibiotics were also elucidated using standard procedures. The aqueous and acetone extracts of the seed were screened for activity against 27 bacterial isolates. The aqueous extract exhibited activity mainly against Gram positive organisms with Minimum inhibitory concentration (MIC) values ranging from 5 mgml-1 – 20 mgml-1, while the acetone extract showed activity against both Gram negative and Gram positive organisms with MIC values ranging from 10 mgml-1 - 0.156 mgml-1. The acetone extract also showed rapid bactericidal activity against Staphylococcus aureus ATCC 6538 with a 3.097 Log10 reduction in counts within 4 hours at 0.3125 mgml-1 and a 1.582 Log10 reduction against Proteus vulgaris CSIR 0030 at 5 mgml-1 after 1 hour. In addition, the aqueous, methanol and acetone extracts of the seeds also exhibited activity against four clinical strains of Staphylococcus isolated from wound sepsis specimens. The MIC values for the aqueous extract were 10 mgml-1 for all the isolates while the acetone and methanol extracts had lower values ranging from 0.3125 - 0.625 mgml-1. The acetone extract was strongly bactericidal against Staphylococcus aureus OKOH3 resulting in a 2.70 Log10 reduction in counts at 1.25 mgml-1 within 4 hours of exposure and a complete elimination of the organism after 8 hours. The bactericidal vi activity of the same extract against Staphylococcus aureus OKOH1 was weak, achieving only a 2.92 Log10 reduction in counts at 1.25 mgml-1 (4× MIC) in 24 hours. In the test for interactions between the acetone extract of the seeds and antibiotics, synergistic interactions were observed largely against Gram positive organisms using the FIC indices, (indices of 0.52 - 0.875) with combinations against Gram negatives yielding largely antagonistic interactions (indices of 2.0 to 5.0). Synergy (≥ 1000 times or ≥ 3 Log10 potentiation of the bactericidal activity) against both Gram negative and Gram positive organisms was detected by time kill assays mainly involving the antibiotics tetracycline, chloramphenicol, amoxycillin and penicillin G. Combinations involving erythromycin and ciprofloxacin consistently gave antagonistic or indifferent interactions. We conclude that the acetone extract of Garcinia kola seeds possess strong bactericidal activities against both Gram positive and Gram negative organisms and can be therapeutically useful in the treatment of bacterial infections including the problematic staphylococcal wound infections. In addition, the acetone extract can be a potential source of broad spectrum resistance modifying compounds that can potentially improve the performance of antibiotics in the treatment of drug resistant infections.
- Full Text:
- Date Issued: 2007
Phytochemical analysis and bioactivity of Garcinia Kola (Heckel) seeds on selected bacterial pathogens
- Seanego, Christinah Tshephisho
- Authors: Seanego, Christinah Tshephisho
- Date: 2012
- Subjects: Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11259 , http://hdl.handle.net/10353/420 , Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
- Description: Garcinia kola is one of the plants used in folklore remedies for the treatment of microbial infections. Bacterial resistance to commonly used antibiotics has necessitated the search for newer and alternative compounds for the treatment of drug resistant microbial infections. This study focuses on the bioactivity of G. kola seeds on Streptococcus pyogenes (ATCC 49399), Staphylococcus aureus (NCTC 6571), Plesiomonas Shigelloides (ATCC 51903) and Salmonella typhimurium (ATCC 13311), organisms which can cause illnesses from mild to severe with potentially fatal outcomes. The crude ethyl acetate, ethanol, methanol, acetone and aqueous extracts were screened by agar-well diffusion method and the activities of the extract were further determined by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays. The inhibition zones ranged from 0 - 24 mm, while MIC and MBC of the extract ranged between 0.04 - 1.25 mg/mL and 0.081 - 2.5 mg/mL respectively. Chloroform/ Ethyl Acetate/ Formic acid (CEF) solvent system separated more active compounds followed by Ethyl Acetate/ Methanol/ Water (EMW) and Benzene/ Ethanol/ Ammonium Hydroxide (BEA). The extracts were fractionated by Thin Layer Chromatography (TLC). Bioautography was used to assess the activity of the possible classes of compounds present in the more active extracts. Column chromatography was used to purify the active compounds from the mixture while Gas Chromatography-Mass Spectrometry (GC-MS) was used to identify the phyto components of the fractions. The MIC of the fractions ranged between 0.0006 - 2.5 mg/mL. CEF 3 (F3), CEF 11 (F11) and CEF 12 (F12) revealed the presence of high levels fatty acids Linoleic acid, 1, 2-Benzenedicarboxylic acid and 2, 3-Dihydro-3, 5-dihydroxy-6-methyl, respectively. The results obtained from this study justify the use of this plant in traditional medicine and provide leads which could be further exploited for the development of new and potent antimicrobials.
- Full Text:
- Date Issued: 2012
- Authors: Seanego, Christinah Tshephisho
- Date: 2012
- Subjects: Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11259 , http://hdl.handle.net/10353/420 , Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
- Description: Garcinia kola is one of the plants used in folklore remedies for the treatment of microbial infections. Bacterial resistance to commonly used antibiotics has necessitated the search for newer and alternative compounds for the treatment of drug resistant microbial infections. This study focuses on the bioactivity of G. kola seeds on Streptococcus pyogenes (ATCC 49399), Staphylococcus aureus (NCTC 6571), Plesiomonas Shigelloides (ATCC 51903) and Salmonella typhimurium (ATCC 13311), organisms which can cause illnesses from mild to severe with potentially fatal outcomes. The crude ethyl acetate, ethanol, methanol, acetone and aqueous extracts were screened by agar-well diffusion method and the activities of the extract were further determined by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays. The inhibition zones ranged from 0 - 24 mm, while MIC and MBC of the extract ranged between 0.04 - 1.25 mg/mL and 0.081 - 2.5 mg/mL respectively. Chloroform/ Ethyl Acetate/ Formic acid (CEF) solvent system separated more active compounds followed by Ethyl Acetate/ Methanol/ Water (EMW) and Benzene/ Ethanol/ Ammonium Hydroxide (BEA). The extracts were fractionated by Thin Layer Chromatography (TLC). Bioautography was used to assess the activity of the possible classes of compounds present in the more active extracts. Column chromatography was used to purify the active compounds from the mixture while Gas Chromatography-Mass Spectrometry (GC-MS) was used to identify the phyto components of the fractions. The MIC of the fractions ranged between 0.0006 - 2.5 mg/mL. CEF 3 (F3), CEF 11 (F11) and CEF 12 (F12) revealed the presence of high levels fatty acids Linoleic acid, 1, 2-Benzenedicarboxylic acid and 2, 3-Dihydro-3, 5-dihydroxy-6-methyl, respectively. The results obtained from this study justify the use of this plant in traditional medicine and provide leads which could be further exploited for the development of new and potent antimicrobials.
- Full Text:
- Date Issued: 2012
The anticancer activity of Cyathula prostrata on two malignant cell lines
- Authors: Schnablegger, Gerald
- Date: 2010
- Subjects: Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10309 , http://hdl.handle.net/10948/1563 , Medicinal plants
- Description: Plants have always been a source of medicine and are still being used by traditional healers in the rural part of Africa, Asia and India to treat a range of illnesses including cancer. The in vitro anticancer activity of an 80 percent ethanol extract of Cyathula prostrata, an annual branching shrub used by traditional healers in Nigeria to treat cancer was investigated. No previous studies have outlined the possible pathways and mechanisms used by cancer cells when treated with C. prostrata. Dose response analysis was performed to determine the effective cytotoxic concentrations of C. prostrata on HeLa (cervical cancer cell line) and U937 (myelo-monocytic cell line). The IC50 values were 100.8 μg/ml and 64.4 μg/ml for HeLa and U937 cells, respectively. All further experiments were performed using 125 μg/ml C. prostrata extract and 50 μM cisplatin as positive control. With the use of the fluorescent DNA binding dye propidium iodide, the induction of tumour cell death by C. prostrata extract has been linked to cell cycle arrest in the G1 phase at 24 and 48 h. In both cell lines, more than 80 percent of the C. prostrata treated cells were found in the G1 phase after 48 hours of treatment. The annexin V-FITC/PI assay revealed an increase in the percentage apoptotic cells from 4.9 percent to 53.1 percent at 24 h and 8.3 percent to 50.3 percent at 48 h. Since apoptosis induction can occur via a number of different pathways, distinct features were used as markers to investigate the mode of action of this C. prostrata extract. Markers such as activated caspase-8, p21 and cyt-c, were investigated with the aid of fluorescently labelled (FITC) antibodies with analysis using flow cytometry. No change in p21 levels was observed in response to treatment with the extract for up to 48 h. Cell cycle arrest in G1 was therefore not induced by this cyclin-CDK inhibitor. Increase in caspase-8 activation was observed in response to treatment with the extract with no cyt-c release from the mitochondria. The lack of cyt-c release was due to no change in mitochondrial membrane potential, which was investigated with the aid of fluorescent mitochondrial dyes and flow cytometric techniques. Caspase-8 activation is unique to the extrinsic apoptotic pathway. The results from this study therefore show that C. prostrata extract induces apoptosis via the extrinsic pathway and that this activation in independent of the mitochondria. The levels of hTERT, the catalytic subunit of telomerase, were investigated as an additional molecular target for C. prostrata. This was also investigated using FITC labelled antibodies and flow cytometry. A decrease in hTERT levels was observed following C. prostrata treatment. The findings from this study suggest that the extract acts through multiple targets, by inducing: cell cycle arrest in the G1 phase through an unknown mechanism; apoptosis through an extrinsic death receptor pathway and replicative senescence through inhibition of telomerase.
- Full Text:
- Date Issued: 2010
- Authors: Schnablegger, Gerald
- Date: 2010
- Subjects: Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10309 , http://hdl.handle.net/10948/1563 , Medicinal plants
- Description: Plants have always been a source of medicine and are still being used by traditional healers in the rural part of Africa, Asia and India to treat a range of illnesses including cancer. The in vitro anticancer activity of an 80 percent ethanol extract of Cyathula prostrata, an annual branching shrub used by traditional healers in Nigeria to treat cancer was investigated. No previous studies have outlined the possible pathways and mechanisms used by cancer cells when treated with C. prostrata. Dose response analysis was performed to determine the effective cytotoxic concentrations of C. prostrata on HeLa (cervical cancer cell line) and U937 (myelo-monocytic cell line). The IC50 values were 100.8 μg/ml and 64.4 μg/ml for HeLa and U937 cells, respectively. All further experiments were performed using 125 μg/ml C. prostrata extract and 50 μM cisplatin as positive control. With the use of the fluorescent DNA binding dye propidium iodide, the induction of tumour cell death by C. prostrata extract has been linked to cell cycle arrest in the G1 phase at 24 and 48 h. In both cell lines, more than 80 percent of the C. prostrata treated cells were found in the G1 phase after 48 hours of treatment. The annexin V-FITC/PI assay revealed an increase in the percentage apoptotic cells from 4.9 percent to 53.1 percent at 24 h and 8.3 percent to 50.3 percent at 48 h. Since apoptosis induction can occur via a number of different pathways, distinct features were used as markers to investigate the mode of action of this C. prostrata extract. Markers such as activated caspase-8, p21 and cyt-c, were investigated with the aid of fluorescently labelled (FITC) antibodies with analysis using flow cytometry. No change in p21 levels was observed in response to treatment with the extract for up to 48 h. Cell cycle arrest in G1 was therefore not induced by this cyclin-CDK inhibitor. Increase in caspase-8 activation was observed in response to treatment with the extract with no cyt-c release from the mitochondria. The lack of cyt-c release was due to no change in mitochondrial membrane potential, which was investigated with the aid of fluorescent mitochondrial dyes and flow cytometric techniques. Caspase-8 activation is unique to the extrinsic apoptotic pathway. The results from this study therefore show that C. prostrata extract induces apoptosis via the extrinsic pathway and that this activation in independent of the mitochondria. The levels of hTERT, the catalytic subunit of telomerase, were investigated as an additional molecular target for C. prostrata. This was also investigated using FITC labelled antibodies and flow cytometry. A decrease in hTERT levels was observed following C. prostrata treatment. The findings from this study suggest that the extract acts through multiple targets, by inducing: cell cycle arrest in the G1 phase through an unknown mechanism; apoptosis through an extrinsic death receptor pathway and replicative senescence through inhibition of telomerase.
- Full Text:
- Date Issued: 2010
Phytochemical analysis and antibacterial properties of aqueous and ethanol extracts of Brachylaena elliptica (Thurb.) dc. and Brachylaena ilicifolia (Lam.) Phill & Schweick
- Authors: Sagbo, Idowu Jonas
- Date: 2015
- Subjects: Medicinal plants , Traditional medicine , Herbs -- Therapeutic use
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11297 , http://hdl.handle.net/10353/d1021289 , Medicinal plants , Traditional medicine , Herbs -- Therapeutic use
- Description: Resistance of human pathogenic bacterial strains results in selective pressure against known antibiotic. However, plant derived compounds that possess antibacterial potential are currently being investigated for treatment of wound infections in diabetic patients as they are inexpensive and non-toxic. Hence, this dissertation was designed to evaluate two medicinal plants (Brachylaena elliptica and Brachylaena ilicifolia) traditionally used in the treatment of various diseases such as diabetes, and its secondary complications in diabetic patients. The in vitro antioxidant activity of both plants were evaluated using DPPH (1, 1-diphenylhydrazl), ferric reducing power, ABTS (2, 2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid), NO (nitric oxide) and H2O2 (hydrogen peroxide) techniques. The antibacterial test and Minimum inhibitory concentration (MIC) was determined by agar dilution method against 5 bacteria strains (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogene, Proteus vulgaris and Proteus mirabilis) infecting wounds in diabetic patients using amoxicillin and ciprofloxacin as positive control. The phytochemical analyses were assessed using standard published methods. Identification of bioactive components in essential oils of both plants were assessed using GCMS. The aqueous and ethanol extracts of both plants were also evaluated to identify bioactive components using LC-MS. The results of the phytochemical analysis revealed the presence of phenols, tannins, flavanoids, flavanols, proanthocyanidins, saponins and alkaloids in both plants. Both plants indicated strong antioxidant activities which might be due to the presence of bioactive compounds. The aqueous and ethanol leaf extracts of both plants demonstrated appreciable broad spectrum activities against these wound pathogens with MIC ranging between 5 and 0.3 mg/ml. The GC-MS analysis of the essential oils of both plants revealed the presence of monoterpenes, oxygenated sesquiterpenes, phenolics and esters. The LC-MS analysis of the aqueous and ethanol leaf extracts of both plants showed that both plants are rich in alkaloids, terpenes, terpenoids, monoterpernoids, and flavanoids. Conclusively, this study has partially justified the ethnomedicinal use of B. elliptica and B.licifolia leaves for the treatment of various diseases, including diabetes and wound infections caused by bacteria in diabetic patients. These may be attributed to the presence of antioxidant compound such as phenols, flavanoids, saponins, tannins, alkaloids and other phytochemical compounds.
- Full Text:
- Date Issued: 2015
- Authors: Sagbo, Idowu Jonas
- Date: 2015
- Subjects: Medicinal plants , Traditional medicine , Herbs -- Therapeutic use
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11297 , http://hdl.handle.net/10353/d1021289 , Medicinal plants , Traditional medicine , Herbs -- Therapeutic use
- Description: Resistance of human pathogenic bacterial strains results in selective pressure against known antibiotic. However, plant derived compounds that possess antibacterial potential are currently being investigated for treatment of wound infections in diabetic patients as they are inexpensive and non-toxic. Hence, this dissertation was designed to evaluate two medicinal plants (Brachylaena elliptica and Brachylaena ilicifolia) traditionally used in the treatment of various diseases such as diabetes, and its secondary complications in diabetic patients. The in vitro antioxidant activity of both plants were evaluated using DPPH (1, 1-diphenylhydrazl), ferric reducing power, ABTS (2, 2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid), NO (nitric oxide) and H2O2 (hydrogen peroxide) techniques. The antibacterial test and Minimum inhibitory concentration (MIC) was determined by agar dilution method against 5 bacteria strains (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogene, Proteus vulgaris and Proteus mirabilis) infecting wounds in diabetic patients using amoxicillin and ciprofloxacin as positive control. The phytochemical analyses were assessed using standard published methods. Identification of bioactive components in essential oils of both plants were assessed using GCMS. The aqueous and ethanol extracts of both plants were also evaluated to identify bioactive components using LC-MS. The results of the phytochemical analysis revealed the presence of phenols, tannins, flavanoids, flavanols, proanthocyanidins, saponins and alkaloids in both plants. Both plants indicated strong antioxidant activities which might be due to the presence of bioactive compounds. The aqueous and ethanol leaf extracts of both plants demonstrated appreciable broad spectrum activities against these wound pathogens with MIC ranging between 5 and 0.3 mg/ml. The GC-MS analysis of the essential oils of both plants revealed the presence of monoterpenes, oxygenated sesquiterpenes, phenolics and esters. The LC-MS analysis of the aqueous and ethanol leaf extracts of both plants showed that both plants are rich in alkaloids, terpenes, terpenoids, monoterpernoids, and flavanoids. Conclusively, this study has partially justified the ethnomedicinal use of B. elliptica and B.licifolia leaves for the treatment of various diseases, including diabetes and wound infections caused by bacteria in diabetic patients. These may be attributed to the presence of antioxidant compound such as phenols, flavanoids, saponins, tannins, alkaloids and other phytochemical compounds.
- Full Text:
- Date Issued: 2015
Pharmaceutical analysis and drug interaction studies : African potato (Hypoxis hemerocallidea)
- Purushothaman Nair, Vipin Devi Prasad
- Authors: Purushothaman Nair, Vipin Devi Prasad
- Date: 2006
- Subjects: Potatoes -- Africa , Potatoes -- Therapeutic use , AIDS (Disease) -- Treatment , HIV infections -- Drug therapy , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3865 , http://hdl.handle.net/10962/d1015802
- Description: In order for a medicinal product to produce a consistent and reliable therapeutic response, it is essential that the final composition of the product is invariable and that the active ingredient/s is/are present in appropriate, non-toxic amounts. However, due to the complexity involved in the standardization of natural products, quality control (QC) criteria and procedures for the registration and market approval of such products are conspicuously absent in most countries around the world. African Potato (AP) is of great medical interest and this particular plant has gained tremendous popularity following the endorsement by the South African Minister of Health as a remedy for HIV/ AIDS patients. Very little information has appeared in the literature to describe methods for the quantitative analysis of hypoxoside, an important component in AP. It has also been claimed that sterols and sterolins present in AP are responsible for its medicinal property but is yet to be proven scientifically. To-date, no QC methods have been reported for the simultaneous quantitative analysis of the combination, β- sitosterol (BSS)/ stigmasterol (STG)/ stigmastanol (STN), purported to be present in preparations containing AP. The effect of concomitant administration of AP and other herbal medicines on the safety and efficacy of conventional medicines has not yet been fully determined. Amongst the objectives of this study was to develop and validate quantitative analytical methods that are suitable for the assay and quality control of plant material, extracts and commercial formulations containing AP. Hypoxoside was isolated from AP and characterized for use as a reference standard for the quality control of AP products and a stability-indicating HPLC/ UV assay method for the quantitative determination of hypoxoside was developed. In addition, a quantitative capillary zone electrophoretic (CZE) method was developed to determine hypoxoside, specifically for its advantages over HPLC. A HPLC method was also developed and validated for the quantitative analysis of BSS, STG and STN in commercially available oral dosage forms containing AP material or extracts thereof. The antioxidant activity of an aqueous extract of lyophilized corms of AP along with hypoxoside and rooperol were investigated. In comparison with the AP extracts and also with hypoxoside, rooperol showed significant antioxidant activity. The capacity of AP, (extracts, formulations, hypoxoside and rooperol as well as sterols to inhibit in vitro metabolism of drug substrates by human cytochrome P450 (CYP) enzymes such as CYP 3A4, 3A5 and CYP19 were investigated. Samples were also assessed for their effect on drug transport proteins such as P-glycoprotein (P-gp). Various extracts of AP, AP formulations, stigmasterol and the norlignans, in particular the aglycone rooperol, exhibited inhibitory effects on CYP 3A4, 3A5 and CYP19 mediated metabolism.These results suggest that concurrent therapy with AP and other medicines, in particular antiretroviral drugs, can have important implications for safety and efficacy. Large discrepancies in marker content between AP products were found. Dissolution testing of AP products was investigated as a QC tool and the results also revealed inconsistencies between different AP products.
- Full Text:
- Date Issued: 2006
- Authors: Purushothaman Nair, Vipin Devi Prasad
- Date: 2006
- Subjects: Potatoes -- Africa , Potatoes -- Therapeutic use , AIDS (Disease) -- Treatment , HIV infections -- Drug therapy , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3865 , http://hdl.handle.net/10962/d1015802
- Description: In order for a medicinal product to produce a consistent and reliable therapeutic response, it is essential that the final composition of the product is invariable and that the active ingredient/s is/are present in appropriate, non-toxic amounts. However, due to the complexity involved in the standardization of natural products, quality control (QC) criteria and procedures for the registration and market approval of such products are conspicuously absent in most countries around the world. African Potato (AP) is of great medical interest and this particular plant has gained tremendous popularity following the endorsement by the South African Minister of Health as a remedy for HIV/ AIDS patients. Very little information has appeared in the literature to describe methods for the quantitative analysis of hypoxoside, an important component in AP. It has also been claimed that sterols and sterolins present in AP are responsible for its medicinal property but is yet to be proven scientifically. To-date, no QC methods have been reported for the simultaneous quantitative analysis of the combination, β- sitosterol (BSS)/ stigmasterol (STG)/ stigmastanol (STN), purported to be present in preparations containing AP. The effect of concomitant administration of AP and other herbal medicines on the safety and efficacy of conventional medicines has not yet been fully determined. Amongst the objectives of this study was to develop and validate quantitative analytical methods that are suitable for the assay and quality control of plant material, extracts and commercial formulations containing AP. Hypoxoside was isolated from AP and characterized for use as a reference standard for the quality control of AP products and a stability-indicating HPLC/ UV assay method for the quantitative determination of hypoxoside was developed. In addition, a quantitative capillary zone electrophoretic (CZE) method was developed to determine hypoxoside, specifically for its advantages over HPLC. A HPLC method was also developed and validated for the quantitative analysis of BSS, STG and STN in commercially available oral dosage forms containing AP material or extracts thereof. The antioxidant activity of an aqueous extract of lyophilized corms of AP along with hypoxoside and rooperol were investigated. In comparison with the AP extracts and also with hypoxoside, rooperol showed significant antioxidant activity. The capacity of AP, (extracts, formulations, hypoxoside and rooperol as well as sterols to inhibit in vitro metabolism of drug substrates by human cytochrome P450 (CYP) enzymes such as CYP 3A4, 3A5 and CYP19 were investigated. Samples were also assessed for their effect on drug transport proteins such as P-glycoprotein (P-gp). Various extracts of AP, AP formulations, stigmasterol and the norlignans, in particular the aglycone rooperol, exhibited inhibitory effects on CYP 3A4, 3A5 and CYP19 mediated metabolism.These results suggest that concurrent therapy with AP and other medicines, in particular antiretroviral drugs, can have important implications for safety and efficacy. Large discrepancies in marker content between AP products were found. Dissolution testing of AP products was investigated as a QC tool and the results also revealed inconsistencies between different AP products.
- Full Text:
- Date Issued: 2006
In-vitro anti-vibrio activities of crude extracts of Garcinia Kola seeds
- Authors: Penduka, Dambudzo
- Date: 2011
- Subjects: Microbial sensitivity tests , Drug resistance in microorganisms , Antibiotics , Garcinia , Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11256 , http://hdl.handle.net/10353/405 , Microbial sensitivity tests , Drug resistance in microorganisms , Antibiotics , Garcinia , Medicinal plants
- Description: The n-Hexane, dichloromethane, methanol and aqueous crude extracts of Garcinia kola (Heckel) seeds were screened for their anti-Vibrio activities against 50 Vibrio bacteria isolated from wastewater final effluents. The 50 isolates consisted of different Vibrio species namely V. fluvialis (14), V. vulnificus (12), V. parahaemolyticus (12), V. metschnikovii (3) and 9 others unidentified to the specie level. The n-Hexane, dichloromethane and methanol extracts had activities against 16 (32 percent) of the Vibrio isolates, while the aqueous extracts had activities against 12 (24 percent) all at a screening concentration of 10 mg/ml. The minimum inhibitory concentrations (MICs) were 0.313-0.625 mg/ml, 0.313-0.625 mg/ml, 0.313-2.5 mg/ml and 10 mg/ml for n-Hexane, dichloromethane, methanol and aqueous extracts respectively. Rate of kill studies were carried out against three different Vibrio species namely V. vulnificus (AL042), V. parahaemolyticus (AL049) and V. fluvialis ( AL040) using the n-Hexane, dichloromethane and methanol extracts at 1× to 4 × MICs and 2 hour exposure. About 96.3 percent, 82.2 percent, and 78.1 percent (V. fluvialis AL040); 92.6 percent, 87.8 percent and 68.9 percent (V. parahaemolyticus AL049); and 91.6 percent, 64.4 percent, 60 percent (V. vulnificus AL042) of the bacteria were killed by the crude n-Hexane, dichloromethane and methanol extracts respectively after 2 hour exposure time at 4× MIC. The patterns of activity were bacteriostatic, with the n-Hexane extracts being most effective in activity. We conclude that the Garcinia kola seeds have promise in the treatment and management of infections caused by Vibrio species.
- Full Text:
- Date Issued: 2011
- Authors: Penduka, Dambudzo
- Date: 2011
- Subjects: Microbial sensitivity tests , Drug resistance in microorganisms , Antibiotics , Garcinia , Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11256 , http://hdl.handle.net/10353/405 , Microbial sensitivity tests , Drug resistance in microorganisms , Antibiotics , Garcinia , Medicinal plants
- Description: The n-Hexane, dichloromethane, methanol and aqueous crude extracts of Garcinia kola (Heckel) seeds were screened for their anti-Vibrio activities against 50 Vibrio bacteria isolated from wastewater final effluents. The 50 isolates consisted of different Vibrio species namely V. fluvialis (14), V. vulnificus (12), V. parahaemolyticus (12), V. metschnikovii (3) and 9 others unidentified to the specie level. The n-Hexane, dichloromethane and methanol extracts had activities against 16 (32 percent) of the Vibrio isolates, while the aqueous extracts had activities against 12 (24 percent) all at a screening concentration of 10 mg/ml. The minimum inhibitory concentrations (MICs) were 0.313-0.625 mg/ml, 0.313-0.625 mg/ml, 0.313-2.5 mg/ml and 10 mg/ml for n-Hexane, dichloromethane, methanol and aqueous extracts respectively. Rate of kill studies were carried out against three different Vibrio species namely V. vulnificus (AL042), V. parahaemolyticus (AL049) and V. fluvialis ( AL040) using the n-Hexane, dichloromethane and methanol extracts at 1× to 4 × MICs and 2 hour exposure. About 96.3 percent, 82.2 percent, and 78.1 percent (V. fluvialis AL040); 92.6 percent, 87.8 percent and 68.9 percent (V. parahaemolyticus AL049); and 91.6 percent, 64.4 percent, 60 percent (V. vulnificus AL042) of the bacteria were killed by the crude n-Hexane, dichloromethane and methanol extracts respectively after 2 hour exposure time at 4× MIC. The patterns of activity were bacteriostatic, with the n-Hexane extracts being most effective in activity. We conclude that the Garcinia kola seeds have promise in the treatment and management of infections caused by Vibrio species.
- Full Text:
- Date Issued: 2011
Assessment of the anti-Listerial properties of Garcinia kola (Heckel) seeds
- Authors: Penduka, Dambudzo
- Date: 2014
- Subjects: Microbial sensitivity tests , Garcinia , Medicinal plants , Traditional medicine
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11278 , http://hdl.handle.net/10353/d1015527 , Microbial sensitivity tests , Garcinia , Medicinal plants , Traditional medicine
- Description: A follow-up of traditional medicinal plants uses is an important tool in highlighting their therapeutic potentials, as they have been found to be a source of a wide range of bioactive compounds that can be used as base compounds for new pharmaceutical drugs. This study therefore focuses on assessing the anti-Listerial properties of the seeds of Garcinia kola (Heckel) plant, which is a traditional medicinal plant of west and central African origin, and was and is still used to traditionally treat several ailments. Four different solvents crude extracts of the seeds were assessed for their anti-Listerial activities in-vitro, against a panel of 42 Listeria bacteria, which included Listeria monocytogenes, Listeria ivanovii and Listeria grayi species. At 10 mg/ml concentration the aqueous extract had activity against 29% of the test isolates while the other three crude extracts namely dichloromethane, n-hexane and the methanol extracts had activity against 45% of the test bacteria. The minimum inhibitory concentration (MIC) ranges of the extracts were 0.079-0.313 mg/ml for the dichloromethane extract; 0.079-0.625 mg/ml for the n-hexane extract; 0.157-0.625 mg/ml for the methanol extract; and 10->10 mg/ml for the aqueous extract. The minimum bactericidal concentration (MBC) ranges of the extracts were 0.625–10 mg/ml for both the n-hexane and the dichloromethane extract; 5-10 mg/ml for the methanol extract; and those for the aqueous extract were above 10 mg/ml against all the susceptible Listeria isolates. The rate of kill analysis was then determined for the three most active crude extracts that is excluding the aqueous extract and it was assessed against four representative Listeria species namely L. monocytogenes (LAL 8), L. grayi (LAL 15), L. ivanovii (LEL 30) and L. ivanovii (LEL 18). All the three extracts showed a general trend of being concentration and time dependent in their rate of kill profiles such that most bacteria cells were killed at the highest test concentration of 4× MIC value after the maximum exposure time of 2 h. The n-hexane, dichloromethane and methanol extracts were bactericidal against 4, 3 and 1 isolates out of the four test Listeria isolates respectively.
- Full Text:
- Date Issued: 2014
- Authors: Penduka, Dambudzo
- Date: 2014
- Subjects: Microbial sensitivity tests , Garcinia , Medicinal plants , Traditional medicine
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11278 , http://hdl.handle.net/10353/d1015527 , Microbial sensitivity tests , Garcinia , Medicinal plants , Traditional medicine
- Description: A follow-up of traditional medicinal plants uses is an important tool in highlighting their therapeutic potentials, as they have been found to be a source of a wide range of bioactive compounds that can be used as base compounds for new pharmaceutical drugs. This study therefore focuses on assessing the anti-Listerial properties of the seeds of Garcinia kola (Heckel) plant, which is a traditional medicinal plant of west and central African origin, and was and is still used to traditionally treat several ailments. Four different solvents crude extracts of the seeds were assessed for their anti-Listerial activities in-vitro, against a panel of 42 Listeria bacteria, which included Listeria monocytogenes, Listeria ivanovii and Listeria grayi species. At 10 mg/ml concentration the aqueous extract had activity against 29% of the test isolates while the other three crude extracts namely dichloromethane, n-hexane and the methanol extracts had activity against 45% of the test bacteria. The minimum inhibitory concentration (MIC) ranges of the extracts were 0.079-0.313 mg/ml for the dichloromethane extract; 0.079-0.625 mg/ml for the n-hexane extract; 0.157-0.625 mg/ml for the methanol extract; and 10->10 mg/ml for the aqueous extract. The minimum bactericidal concentration (MBC) ranges of the extracts were 0.625–10 mg/ml for both the n-hexane and the dichloromethane extract; 5-10 mg/ml for the methanol extract; and those for the aqueous extract were above 10 mg/ml against all the susceptible Listeria isolates. The rate of kill analysis was then determined for the three most active crude extracts that is excluding the aqueous extract and it was assessed against four representative Listeria species namely L. monocytogenes (LAL 8), L. grayi (LAL 15), L. ivanovii (LEL 30) and L. ivanovii (LEL 18). All the three extracts showed a general trend of being concentration and time dependent in their rate of kill profiles such that most bacteria cells were killed at the highest test concentration of 4× MIC value after the maximum exposure time of 2 h. The n-hexane, dichloromethane and methanol extracts were bactericidal against 4, 3 and 1 isolates out of the four test Listeria isolates respectively.
- Full Text:
- Date Issued: 2014
Biochemical evaluation of Tulbaghia violacea harv.rhizomes in diet induced hypercholestrolemic rats
- Olorunnisola, Olubukola Sinbad
- Authors: Olorunnisola, Olubukola Sinbad
- Date: 2012
- Subjects: Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD (Biochemistry)
- Identifier: vital:11273 , http://hdl.handle.net/10353/d1006900 , Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Description: Discovery of cheap, nontoxic and readily available antiatherosclerotic drugs is an extraordinary challenge in this modern world. Atherosclerosis and cardiovascular diseases have been predicted to be the leading cause of death by the year 2030. Hence, this thesis was designed to search for plant (s) with anti-atherogenic properties, investigate its possible side effects and extrapolate its likely mechanism(s) of action. An ethnobotanical survey was employed in identification of locally important plants used for the management and treatment of cardiovascular diseases and its predisposing factors in Nkonkobe Municipality, Eastern Cape in South Africa. Information on the names of plants, their parts used and methods of preparation was collected through a questionnaire which was administered to herbalists, traditional healers and rural dwellers. The most frequently used plant (Rhizomes of Tulbaghia violacea Harv.) was investigated for toxicity using brine shrimp lethality (in vitro) and in vivo toxicity test (acute and subchronic) on rats to determine safety dosage. The in vitro antioxidant and free radical scavenging activity of the plant was investigated using models such as 1,1-diphenyl-2- picrylhydrazyl (DPPH), superoxide anions, hydrogen peroxide (H2O2), nitric oxide (NO), 2,2’- azinobis [3-ethylbenzothiazoline-6-sulfonic acid] diammonium salt (ABTS), lipid peroxidation inhibition and the ferric reducing agent. Phytochemical content and the effect of oral administration of fresh methanolic extract rhizomes of Tulbaghia violacea (250, 500 mg/kg. bwt/day) on Lipid peroxidation (TBARS), serum and tissue antioxidant enzymes in normal, hypercholesterolemic and diet induced atherogenic rats were also assessed. More so, the potential of the extract (250 and 500 mg/kg. bwt) to protect against atherogenic diet (4 percentage cholesterol 1 pecentage cholic acid and 0.5 percentage thiouracil) induced fatty streaks formation, dyslipidemia, oxidative stress and endothelial dysfunction was also investigated. Ethnobotanical study revealed that 19 plant species are used for the treatment of heart related diseases in the Municipality. 53 percentage of the plants mentioned were used for the management of chest pain, 47 percentage for high blood pressure, 42 percent for heart disease, 16 percentage for stroke and 11 percentage for the treatment of hypercholesterolemia. Tulbaghia violacea was repeatedly mentioned as the plant species used for the treatment of high blood pressure and predisposing factors in the study area. The brine shrimp cytotoxicity test revealed that fresh, dried methanolic extracts and essential oil of the T. violacea exhibited a high degree of cytotoxic activity with IC50 values of 18.18 (fresh) and 19.24 (dried) μg/ml. An IC50 value of 12. 59 μg/ml was obtained for the essential oil of the plant. The low cytotoxicity values obtained, suggested that rhizome of T. violacea may serve as a potential source of antimicrobial and anticancer agents. In vivo acute study of single oral administration of 5g/kg dose does not produce mortality or significant behavioral changes during 14 days observation. In the sub-chronic study, the extract (250, 500 mg/kg/bwt/ day) administered for a period of 28 days showed no mortality or morbidity. The weekly body and organ weight of the rats showed no significant differences between the control and the rats treated with the extract. The extract at all doses does not show any effect on of biomarkers of liver or renal damage. However, a significant decrease in the activity of ƔGT was observed in the extract treated groups. Hematological evaluation revealed that oral administration of fresh methanolic extracts of rhizomes of T. violacea does not cause anaemia or leucocytosis in the animals. Furthermore, histopathology results of the internal organs revealed no detectable inflammation. These results demonstrated that the rhizome extract of T. violacea was potentially safe for consumption orally even in chronic concentration. In vitro antioxidant evaluation showed that the essential oil, fresh and dried methanolic extracts exhibited potent antioxidant activities in a concentration dependent manner. Phytochemical investigation reveals that the fresh and the dry extract of RTV are rich in flavonoid, flavonol, phenols, tannin and proanthocyanidin, while the essential oil contained dimethy disulfide, dimethyl trisulfide, (methyl methylthio) methyl, 2,4-dithiapentane (11.35 percent) and (methylthio) acetic acid, 2- (methylthio) ethanol, 3-(methylthio) - and propanenitrile (7.20 percent). The fresh extract had higher radicals scavenging activity than the essential oil or dried extract, with 50 percentage inhibition of DPPH, hydrogen peroxide and lipid peroxidation at a concentration of 35.0 ± 0.12, 19.3 ± 0.11 and 17.9 ± 0.15 μg/ml respectively. Oral administration of methanolic extract of RTV in 125, 250 and 500 mg/kg to female Wistar rats significantly inhibited reduction of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). The extracts also inhibited (p< 0.05) lipid peroxidation in normal, high cholesterol and diet induced atherosclerosis fed rats in a dose dependant manner. Also the extract (250 and 500 mg/kg/bwt/day) caused a significant (p<0.05) improvement in body weight of treated animals compared with untreated hypercholesterolemia control rats. The extracts also protected significantly (p<0.05) against atherogenic diet induced liver damage or fatty streaks formation in the aorta as revealed by histological examination. The anti-cholesterolemia and anti-atherosclerotic activities of the extract compared favorably well with standard drugs Gemfibrozil and Atorvastatin respectively. Conclusively, rhizomes of T. violacea possess significant anti-atherogenic activity and its mechanism of action(s) may be due to its antioxidant and anti-hypercholesterolemia properties. The results of this study also suggested that rhizome of T. violacea is relatively safe for human consumption and it may be used as an alternative to garlic.
- Full Text:
- Date Issued: 2012
- Authors: Olorunnisola, Olubukola Sinbad
- Date: 2012
- Subjects: Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD (Biochemistry)
- Identifier: vital:11273 , http://hdl.handle.net/10353/d1006900 , Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Description: Discovery of cheap, nontoxic and readily available antiatherosclerotic drugs is an extraordinary challenge in this modern world. Atherosclerosis and cardiovascular diseases have been predicted to be the leading cause of death by the year 2030. Hence, this thesis was designed to search for plant (s) with anti-atherogenic properties, investigate its possible side effects and extrapolate its likely mechanism(s) of action. An ethnobotanical survey was employed in identification of locally important plants used for the management and treatment of cardiovascular diseases and its predisposing factors in Nkonkobe Municipality, Eastern Cape in South Africa. Information on the names of plants, their parts used and methods of preparation was collected through a questionnaire which was administered to herbalists, traditional healers and rural dwellers. The most frequently used plant (Rhizomes of Tulbaghia violacea Harv.) was investigated for toxicity using brine shrimp lethality (in vitro) and in vivo toxicity test (acute and subchronic) on rats to determine safety dosage. The in vitro antioxidant and free radical scavenging activity of the plant was investigated using models such as 1,1-diphenyl-2- picrylhydrazyl (DPPH), superoxide anions, hydrogen peroxide (H2O2), nitric oxide (NO), 2,2’- azinobis [3-ethylbenzothiazoline-6-sulfonic acid] diammonium salt (ABTS), lipid peroxidation inhibition and the ferric reducing agent. Phytochemical content and the effect of oral administration of fresh methanolic extract rhizomes of Tulbaghia violacea (250, 500 mg/kg. bwt/day) on Lipid peroxidation (TBARS), serum and tissue antioxidant enzymes in normal, hypercholesterolemic and diet induced atherogenic rats were also assessed. More so, the potential of the extract (250 and 500 mg/kg. bwt) to protect against atherogenic diet (4 percentage cholesterol 1 pecentage cholic acid and 0.5 percentage thiouracil) induced fatty streaks formation, dyslipidemia, oxidative stress and endothelial dysfunction was also investigated. Ethnobotanical study revealed that 19 plant species are used for the treatment of heart related diseases in the Municipality. 53 percentage of the plants mentioned were used for the management of chest pain, 47 percentage for high blood pressure, 42 percent for heart disease, 16 percentage for stroke and 11 percentage for the treatment of hypercholesterolemia. Tulbaghia violacea was repeatedly mentioned as the plant species used for the treatment of high blood pressure and predisposing factors in the study area. The brine shrimp cytotoxicity test revealed that fresh, dried methanolic extracts and essential oil of the T. violacea exhibited a high degree of cytotoxic activity with IC50 values of 18.18 (fresh) and 19.24 (dried) μg/ml. An IC50 value of 12. 59 μg/ml was obtained for the essential oil of the plant. The low cytotoxicity values obtained, suggested that rhizome of T. violacea may serve as a potential source of antimicrobial and anticancer agents. In vivo acute study of single oral administration of 5g/kg dose does not produce mortality or significant behavioral changes during 14 days observation. In the sub-chronic study, the extract (250, 500 mg/kg/bwt/ day) administered for a period of 28 days showed no mortality or morbidity. The weekly body and organ weight of the rats showed no significant differences between the control and the rats treated with the extract. The extract at all doses does not show any effect on of biomarkers of liver or renal damage. However, a significant decrease in the activity of ƔGT was observed in the extract treated groups. Hematological evaluation revealed that oral administration of fresh methanolic extracts of rhizomes of T. violacea does not cause anaemia or leucocytosis in the animals. Furthermore, histopathology results of the internal organs revealed no detectable inflammation. These results demonstrated that the rhizome extract of T. violacea was potentially safe for consumption orally even in chronic concentration. In vitro antioxidant evaluation showed that the essential oil, fresh and dried methanolic extracts exhibited potent antioxidant activities in a concentration dependent manner. Phytochemical investigation reveals that the fresh and the dry extract of RTV are rich in flavonoid, flavonol, phenols, tannin and proanthocyanidin, while the essential oil contained dimethy disulfide, dimethyl trisulfide, (methyl methylthio) methyl, 2,4-dithiapentane (11.35 percent) and (methylthio) acetic acid, 2- (methylthio) ethanol, 3-(methylthio) - and propanenitrile (7.20 percent). The fresh extract had higher radicals scavenging activity than the essential oil or dried extract, with 50 percentage inhibition of DPPH, hydrogen peroxide and lipid peroxidation at a concentration of 35.0 ± 0.12, 19.3 ± 0.11 and 17.9 ± 0.15 μg/ml respectively. Oral administration of methanolic extract of RTV in 125, 250 and 500 mg/kg to female Wistar rats significantly inhibited reduction of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). The extracts also inhibited (p< 0.05) lipid peroxidation in normal, high cholesterol and diet induced atherosclerosis fed rats in a dose dependant manner. Also the extract (250 and 500 mg/kg/bwt/day) caused a significant (p<0.05) improvement in body weight of treated animals compared with untreated hypercholesterolemia control rats. The extracts also protected significantly (p<0.05) against atherogenic diet induced liver damage or fatty streaks formation in the aorta as revealed by histological examination. The anti-cholesterolemia and anti-atherosclerotic activities of the extract compared favorably well with standard drugs Gemfibrozil and Atorvastatin respectively. Conclusively, rhizomes of T. violacea possess significant anti-atherogenic activity and its mechanism of action(s) may be due to its antioxidant and anti-hypercholesterolemia properties. The results of this study also suggested that rhizome of T. violacea is relatively safe for human consumption and it may be used as an alternative to garlic.
- Full Text:
- Date Issued: 2012
Biological activities and mechanisms of action of two ethnobotanically selected South African medicinal plants on some bacteria associated with gastrointestinal infections
- Olajuyigbe, Olufunmiso Olusola https://orcid.org/0000-0002-7889-0416
- Authors: Olajuyigbe, Olufunmiso Olusola https://orcid.org/0000-0002-7889-0416
- Date: 2012-08
- Subjects: Medicinal plants , Herbs -- Therapeutic use , Gastrointestinal system
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/25439 , vital:64249
- Description: In this study, 36 plant species representing 24 families were found to be commonly used for the treatment of a variety of gastrointestinal disorders in Eastern Cape, South Africa. The family Fabaceae had the highest number of species. Out of these, 47.06percent were used in the treatment of dysentery alone while 46.15percent were used in the treatment of diarrhoea. Acacia mearnsii De Wild and Ziziphus mucronata subsp. mucronata Willd were selected for this research because they are extensively used in folkloric medicine in South Africa and there was lack of scientific reports that documented their biological activities. The phytochemical screening, antioxidant activities, in vitro antimicrobial activities, cytotoxicity, the synergistic potentials and mechanisms of actions of these plants were investigated. The phytochemical screening and the antioxidant activities of the two species showed that the quantity of the phenolic compounds, flavonoids and proanthocyanidins detected differ significantly in the various extracts. Of the aqueous, acetone, ethanolic and methanolic extracts of A. mearnsii, the ethanolic extract had the highest flavonoids while the acetone extract had the highest phenolic contents. The proanthocyanidins were highest in the methanol extract while aqueous extracts had the least phytochemicals. Aqueous extract showed the least ferric reducing power but methanol extract indicated the highest reducing power. The reducing power of the extracts was lower than those obtained from the reference standard such as butylated hydroxytoluene (BHT), rutin and ascorbic acid. 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) diammonium salt showed that ethanol extract exhibited the highest antioxidant activity at the highest concentration tested. Also, 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay indicated that ethanol extract had the highest radical scavenging activity at the lowest concentration and the activities of all the extracts decreased with increase in their concentrations. In Z. mucronata subsp. mucronata, the phenolics were significantly higher than the flavonoids and proanthocyanidin contents in all the extracts investigated. The ethanol extract had the highest antioxidant activity, followed by the acetone extract while the aqueous extract was the least active. Reacting with ABTS, the 50percent inhibitory concentrations (IC50) were (0.0429 ± 0.04 mg/ml) for aqueous, (0.0317 ± 0.04 mg/ml) for acetone and (0.0306 ± 0.04 mg/ml) for ethanol extracts while they inhibited DPPH radical with 50percent inhibitory concentration (IC50) values of 0.0646 ± 0.02 mg/ml (aqueous), 0.0482 ± 0.02 mg/ml (acetone) and 0.0422 ± 0.03 mg/ml (ethanol). The investigation showed that a positive linear correlation existed between the total phenolic content and antioxidant activity of the extracts and that these plants have strong antioxidant property and free radical scavenging capability. The in vitro antibacterial activities of Acacia mearnsii and Z. mucronata subsp. mucronata showed that their minimum inhibitory concentrations ranged between 0.039 mg/ml and 1.25 mg/ml. With the exception of acetone extract of A. mearnsii having MICs greater than 1.0 mg/ml for Enterococcus faecalis ATCC 29212 and Bacillus subtilis KZN, all other isolates had MICs less than 0.7 mg/ml. In all the bacteria treated with Z. mucronata subsp. mucronata extracts, Enterobacter cloacae ATCC 13047 had MIC greater than 1 mg/ml in methanol extract, Enterococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 6538 had MICs greater than 1 mg/ml in acetone extract while all other isolates were highly susceptible to the different extracts of Z. mucronata subsp. mucronata and had MICs less than 0.7 mg/ml. While aqueous extract was as active as the alcoholic extracts in A. mearnsii, that of Z. mucronata had no effect. The ethanol extracts exhibited the highest degree of antibacterial activity in both plants. This study, also, showed that the antifungal activity of A. mearnsii ranging 0.3125 – 5.0 mg/ml was higher than those of the different extracts of Z. mucronata subsp. mucronata ranging 1.25 – 10.0 mg/ml. It is evident from the results of the brine shrimp lethality assay that the crude extracts of A. mearnsii with the LC50 equaled 112.36 µg/ml and having the highest levels of toxicity (100percent) death at 500 μg/ml was non toxic (LC50 > 100 μg/ml) while the LC50 for Z. mucronata subsp. mucronata equaled 90.27 µg/ml indicated a low level of toxicity. The effects of combining the crude extracts of these plants with eight antibiotics were investigated by means of checkerboard and agar diffusion methods. On using the methanol extract of A. mearnsii, the agar diffusion assay showed that extract-kanamycin combination had zones of inhibition ≥ 20 ± 1.0 mm in all the bacteria tested (100percent), followed by extract chloramphenicol (90percent) > extract-ciprofloxacin = extract-tetracycline (70percent) > extract amoxicillin (60percent) > extract-nalidixic acid (50percent) > extract-erythromycin (40percent) > extract metronidazole (20percent). The checkerboard showed synergistic interaction (61.25percent), additivity/indifference (23.75percent) and antagonistic (15percent) effects. I, therefore, concluded that the antibacterial potentials of the antibiotics were improved and combining natural products with antibiotic could be a potential source of resistance-modifying agents useful against multi-drug resistant bacteria. The influences of these extracts on the ultrastructures, elemental components, protein and lipid leakages of five different bacteria were determined as the possible mechanisms of action of the extracts investigated. The scanning electron microscopy indicated varied ultrastructural changes in the morphology of bacterial cells treated with the extracts. The X-ray microanalysis showed significant differences between the elemental contents of extract-treated and untreated bacteria while lipids and proteins were leaked to a great extent from the extract-treated bacterial strains in comparison with the untreated ones. The possible mechanisms of action of the extracts may include inhibition of a significant step in peptidoglycan assembly, inhibition of metabolic processes, disruption of cell wall and cell membranes resulting in the efflux of lipid and protein in all the bacteria tested. The possible mechanism of action involved in the lipid and protein leakages in the bacterial cells could be attributed to lipid peroxidation and protein oxidation owing to the antioxidant activities of the extracts that were active beyond the protective levels. I concluded that the morphological changes and the observed leakages showed rapid killing, significant membrane depolarization resulting in leakages and efflux of disintegrated cellular materials. In general, this study has justified the ethnotherapeutic importance of A. mearnsii and Z. mucronata subsp. mucronata in the treatment of microbial infections by indicating the possible mechanisms of action of the crude extracts on the tested bacteria. , Thesis (PhD) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Date Issued: 2012-08
- Authors: Olajuyigbe, Olufunmiso Olusola https://orcid.org/0000-0002-7889-0416
- Date: 2012-08
- Subjects: Medicinal plants , Herbs -- Therapeutic use , Gastrointestinal system
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/25439 , vital:64249
- Description: In this study, 36 plant species representing 24 families were found to be commonly used for the treatment of a variety of gastrointestinal disorders in Eastern Cape, South Africa. The family Fabaceae had the highest number of species. Out of these, 47.06percent were used in the treatment of dysentery alone while 46.15percent were used in the treatment of diarrhoea. Acacia mearnsii De Wild and Ziziphus mucronata subsp. mucronata Willd were selected for this research because they are extensively used in folkloric medicine in South Africa and there was lack of scientific reports that documented their biological activities. The phytochemical screening, antioxidant activities, in vitro antimicrobial activities, cytotoxicity, the synergistic potentials and mechanisms of actions of these plants were investigated. The phytochemical screening and the antioxidant activities of the two species showed that the quantity of the phenolic compounds, flavonoids and proanthocyanidins detected differ significantly in the various extracts. Of the aqueous, acetone, ethanolic and methanolic extracts of A. mearnsii, the ethanolic extract had the highest flavonoids while the acetone extract had the highest phenolic contents. The proanthocyanidins were highest in the methanol extract while aqueous extracts had the least phytochemicals. Aqueous extract showed the least ferric reducing power but methanol extract indicated the highest reducing power. The reducing power of the extracts was lower than those obtained from the reference standard such as butylated hydroxytoluene (BHT), rutin and ascorbic acid. 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) diammonium salt showed that ethanol extract exhibited the highest antioxidant activity at the highest concentration tested. Also, 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay indicated that ethanol extract had the highest radical scavenging activity at the lowest concentration and the activities of all the extracts decreased with increase in their concentrations. In Z. mucronata subsp. mucronata, the phenolics were significantly higher than the flavonoids and proanthocyanidin contents in all the extracts investigated. The ethanol extract had the highest antioxidant activity, followed by the acetone extract while the aqueous extract was the least active. Reacting with ABTS, the 50percent inhibitory concentrations (IC50) were (0.0429 ± 0.04 mg/ml) for aqueous, (0.0317 ± 0.04 mg/ml) for acetone and (0.0306 ± 0.04 mg/ml) for ethanol extracts while they inhibited DPPH radical with 50percent inhibitory concentration (IC50) values of 0.0646 ± 0.02 mg/ml (aqueous), 0.0482 ± 0.02 mg/ml (acetone) and 0.0422 ± 0.03 mg/ml (ethanol). The investigation showed that a positive linear correlation existed between the total phenolic content and antioxidant activity of the extracts and that these plants have strong antioxidant property and free radical scavenging capability. The in vitro antibacterial activities of Acacia mearnsii and Z. mucronata subsp. mucronata showed that their minimum inhibitory concentrations ranged between 0.039 mg/ml and 1.25 mg/ml. With the exception of acetone extract of A. mearnsii having MICs greater than 1.0 mg/ml for Enterococcus faecalis ATCC 29212 and Bacillus subtilis KZN, all other isolates had MICs less than 0.7 mg/ml. In all the bacteria treated with Z. mucronata subsp. mucronata extracts, Enterobacter cloacae ATCC 13047 had MIC greater than 1 mg/ml in methanol extract, Enterococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 6538 had MICs greater than 1 mg/ml in acetone extract while all other isolates were highly susceptible to the different extracts of Z. mucronata subsp. mucronata and had MICs less than 0.7 mg/ml. While aqueous extract was as active as the alcoholic extracts in A. mearnsii, that of Z. mucronata had no effect. The ethanol extracts exhibited the highest degree of antibacterial activity in both plants. This study, also, showed that the antifungal activity of A. mearnsii ranging 0.3125 – 5.0 mg/ml was higher than those of the different extracts of Z. mucronata subsp. mucronata ranging 1.25 – 10.0 mg/ml. It is evident from the results of the brine shrimp lethality assay that the crude extracts of A. mearnsii with the LC50 equaled 112.36 µg/ml and having the highest levels of toxicity (100percent) death at 500 μg/ml was non toxic (LC50 > 100 μg/ml) while the LC50 for Z. mucronata subsp. mucronata equaled 90.27 µg/ml indicated a low level of toxicity. The effects of combining the crude extracts of these plants with eight antibiotics were investigated by means of checkerboard and agar diffusion methods. On using the methanol extract of A. mearnsii, the agar diffusion assay showed that extract-kanamycin combination had zones of inhibition ≥ 20 ± 1.0 mm in all the bacteria tested (100percent), followed by extract chloramphenicol (90percent) > extract-ciprofloxacin = extract-tetracycline (70percent) > extract amoxicillin (60percent) > extract-nalidixic acid (50percent) > extract-erythromycin (40percent) > extract metronidazole (20percent). The checkerboard showed synergistic interaction (61.25percent), additivity/indifference (23.75percent) and antagonistic (15percent) effects. I, therefore, concluded that the antibacterial potentials of the antibiotics were improved and combining natural products with antibiotic could be a potential source of resistance-modifying agents useful against multi-drug resistant bacteria. The influences of these extracts on the ultrastructures, elemental components, protein and lipid leakages of five different bacteria were determined as the possible mechanisms of action of the extracts investigated. The scanning electron microscopy indicated varied ultrastructural changes in the morphology of bacterial cells treated with the extracts. The X-ray microanalysis showed significant differences between the elemental contents of extract-treated and untreated bacteria while lipids and proteins were leaked to a great extent from the extract-treated bacterial strains in comparison with the untreated ones. The possible mechanisms of action of the extracts may include inhibition of a significant step in peptidoglycan assembly, inhibition of metabolic processes, disruption of cell wall and cell membranes resulting in the efflux of lipid and protein in all the bacteria tested. The possible mechanism of action involved in the lipid and protein leakages in the bacterial cells could be attributed to lipid peroxidation and protein oxidation owing to the antioxidant activities of the extracts that were active beyond the protective levels. I concluded that the morphological changes and the observed leakages showed rapid killing, significant membrane depolarization resulting in leakages and efflux of disintegrated cellular materials. In general, this study has justified the ethnotherapeutic importance of A. mearnsii and Z. mucronata subsp. mucronata in the treatment of microbial infections by indicating the possible mechanisms of action of the crude extracts on the tested bacteria. , Thesis (PhD) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Date Issued: 2012-08
Chemical transformations and phytochemical studies of bioactive components from extracts of Rosmarinus officinalis L
- Authors: Okoh, Omobola Oluranti
- Date: 2010
- Subjects: Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11331 , http://hdl.handle.net/10353/354 , Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Description: Variations in the yield, chemical composition, antibacterial, and antioxidant properties of the essential oils of Rosmarinus officinalis L. cultivated in Alice, Eastern Cape of South Africa over a period of 12 months using the solvent-free microwave extraction and traditional hydrodistillation methods were evaluated. The GC-MS analyses of the essential oils revealed the presence of 33 compounds with 1,8-cineole, a-pinene, camphor, verbenone, bornyl acetate and camphene constituting about 80 percent of the oils throughout the period of investigation, with the solvent-free microwave extraction method generally yielding more of the major components than the hydrodistillation method. Each of the major components of the oils varied in quantity and quality of yield at different periods of the year. The method of extraction and time of harvest are of importance to the quantity and quality of essential oil of Rosmarinus officinalis. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene- 4-ol, linalool, a-terpeneol were present in the oil of SFME in comparison with HD. However, HD oil contained more monoterpene hydrocarbons such as a-pinene, camphene, β-pinene, myrcene, a-phellanderene, 1,8-cineole, trans- β-ocimene, γ-teprinene, and cis-sabinene hydrate than SFME extracted oil. Accumulation of monoterpene alcohols and ketones was observed during maturation process of Rosmarinus leaves. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration values were determined using a serial microplate dilution method. The essential oils obtained using both methods of extraction were active against all the bacteria tested at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the SFME extracted oils ranged between 0.23 and 1.88 mg mL-1, while those of the HD extracted oils varied between 0.94 and 7.5 mg mL-1, thus suggesting that the oil obtained by solvent free microwave extraction was more active against bacteria than the oil obtained through hydrodistillation. The antioxidant and free radical scavenging activity of the obtained oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay and β- carotene bleaching test. In the DPPH+ assay, while the free radical scavenging activity of the oil obtained by SFME method showed percentage inhibitions of between 48.8 percent and 67 percent, the HD derived oil showed inhibitions of between 52.2 percent and 65.30 percent at concentrations of 0.33, 0.50 and 1.0 mg mL-1, respectively. In the β-carotene bleaching assay, the percentage inhibition increased with increasing concentration of both oils with a higher antioxidant activity of the oil obtained through the SFME than the HD method. Thin layer chromatography (TLC) was used to analyze the chemical composition of the extracts using three eluent solvent systems of varying polarities i. e. CEF, BEA and EMW and sprayed with vanillin-sulfuric acid. The chemical composition of the different extracts was similar with the exception of methanol and water extracts which had only one or two visible compounds after treating with vanillin-spray reagent. To evaluate the number of antibacterial compounds present in the fractions, bioautography was used against two most important nosocomial microorganisms. S. aureus (Gram positive) and E. coli (Gram negative). Nearly all the crude serial extraction fractions contained compounds that inhibited the growth of E. coli. The hexane extract had the most lines of inhibition followed by ethyl acetate. Bioassay-guided fractionation against E. coli was used to isolate antibacterial compounds. The largest number of antibacterial compounds occurred in the hexane fraction. Furthermore we tried to complete the characterization by extracting and studying other biologically important plant metabolites such as phenolic compounds to evaluate the antioxidant capacity of Rosmarinus extracts.
- Full Text:
- Date Issued: 2010
- Authors: Okoh, Omobola Oluranti
- Date: 2010
- Subjects: Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11331 , http://hdl.handle.net/10353/354 , Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Description: Variations in the yield, chemical composition, antibacterial, and antioxidant properties of the essential oils of Rosmarinus officinalis L. cultivated in Alice, Eastern Cape of South Africa over a period of 12 months using the solvent-free microwave extraction and traditional hydrodistillation methods were evaluated. The GC-MS analyses of the essential oils revealed the presence of 33 compounds with 1,8-cineole, a-pinene, camphor, verbenone, bornyl acetate and camphene constituting about 80 percent of the oils throughout the period of investigation, with the solvent-free microwave extraction method generally yielding more of the major components than the hydrodistillation method. Each of the major components of the oils varied in quantity and quality of yield at different periods of the year. The method of extraction and time of harvest are of importance to the quantity and quality of essential oil of Rosmarinus officinalis. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene- 4-ol, linalool, a-terpeneol were present in the oil of SFME in comparison with HD. However, HD oil contained more monoterpene hydrocarbons such as a-pinene, camphene, β-pinene, myrcene, a-phellanderene, 1,8-cineole, trans- β-ocimene, γ-teprinene, and cis-sabinene hydrate than SFME extracted oil. Accumulation of monoterpene alcohols and ketones was observed during maturation process of Rosmarinus leaves. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration values were determined using a serial microplate dilution method. The essential oils obtained using both methods of extraction were active against all the bacteria tested at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the SFME extracted oils ranged between 0.23 and 1.88 mg mL-1, while those of the HD extracted oils varied between 0.94 and 7.5 mg mL-1, thus suggesting that the oil obtained by solvent free microwave extraction was more active against bacteria than the oil obtained through hydrodistillation. The antioxidant and free radical scavenging activity of the obtained oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay and β- carotene bleaching test. In the DPPH+ assay, while the free radical scavenging activity of the oil obtained by SFME method showed percentage inhibitions of between 48.8 percent and 67 percent, the HD derived oil showed inhibitions of between 52.2 percent and 65.30 percent at concentrations of 0.33, 0.50 and 1.0 mg mL-1, respectively. In the β-carotene bleaching assay, the percentage inhibition increased with increasing concentration of both oils with a higher antioxidant activity of the oil obtained through the SFME than the HD method. Thin layer chromatography (TLC) was used to analyze the chemical composition of the extracts using three eluent solvent systems of varying polarities i. e. CEF, BEA and EMW and sprayed with vanillin-sulfuric acid. The chemical composition of the different extracts was similar with the exception of methanol and water extracts which had only one or two visible compounds after treating with vanillin-spray reagent. To evaluate the number of antibacterial compounds present in the fractions, bioautography was used against two most important nosocomial microorganisms. S. aureus (Gram positive) and E. coli (Gram negative). Nearly all the crude serial extraction fractions contained compounds that inhibited the growth of E. coli. The hexane extract had the most lines of inhibition followed by ethyl acetate. Bioassay-guided fractionation against E. coli was used to isolate antibacterial compounds. The largest number of antibacterial compounds occurred in the hexane fraction. Furthermore we tried to complete the characterization by extracting and studying other biologically important plant metabolites such as phenolic compounds to evaluate the antioxidant capacity of Rosmarinus extracts.
- Full Text:
- Date Issued: 2010
Variation in the essential oil composition of Calendula Officinalis L
- Authors: Okoh, Omobola Oluranti
- Date: 2008
- Subjects: Calendula (Genus) , Essences and essential oils , Medicinal plants , Calendula officinalis
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11334 , http://hdl.handle.net/10353/d1001150 , Calendula (Genus) , Essences and essential oils , Medicinal plants , Calendula officinalis
- Description: Variations in the yield, chemical composition, antibacterial, and antioxidant properties of the essential oils of Rosmarinus officinalis L. cultivated in Alice, Eastern Cape of South Africa over a period of 12 months using the solvent-free microwave extraction and traditional hydrodistillation methods were evaluated. The GC-MS analyses of the essential oils revealed the presence of 33 compounds with 1,8-cineole, a-pinene, camphor, verbenone, bornyl acetate and camphene constituting about 80 percent of the oils throughout the period of investigation, with the solvent-free microwave extraction method generally yielding more of the major components than the hydrodistillation method. Each of the major components of the oils varied in quantity and quality of yield at different periods of the year. The method of extraction and time of harvest are of importance to the quantity and quality of essential oil of Rosmarinus officinalis. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene- 4-ol, linalool, a-terpeneol were present in the oil of SFME in comparison with HD. However, HD oil contained more monoterpene hydrocarbons such as a-pinene, camphene, β-pinene, myrcene, a-phellanderene, 1,8-cineole, trans- β-ocimene, γ-teprinene, and cis-sabinene hydrate than SFME extracted oil. Accumulation of monoterpene alcohols and ketones was observed during maturation process of Rosmarinus leaves. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration values were determined using a serial microplate dilution method. The essential oils obtained using both methods of extraction were active against all the bacteria tested at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the SFME extracted oils ranged between 0.23 and 1.88 mg mL-1, while those of the HD extracted oils varied between 0.94 and 7.5 mg mL-1, thus suggesting that the oil obtained by solvent free microwave extraction was more active against bacteria than the oil obtained through hydrodistillation. The antioxidant and free radical scavenging activity of the obtained oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay and β- carotene bleaching test. In the DPPH+ assay, while the free radical scavenging activity of the oil obtained by SFME method showed percentage inhibitions of between 48.8 percent and 67 percent, the HD derived oil showed inhibitions of between 52.2 percent and 65.30 percent at concentrations of 0.33, 0.50 and 1.0 mg mL-1, respectively. In the β-carotene bleaching assay, the percentage inhibition increased with increasing concentration of both oils with a higher antioxidant activity of the oil obtained through the SFME than the HD method. Thin layer chromatography (TLC) was used to analyze the chemical composition of the extracts using three eluent solvent systems of varying polarities i. e. CEF, BEA and EMW and sprayed with vanillin-sulfuric acid. The chemical composition of the different extracts was similar with the exception of methanol and water extracts which had only one or two visible compounds after treating with vanillin-spray reagent. To evaluate the number of antibacterial compounds present in the fractions, bioautography was used against two most important nosocomial microorganisms. S. aureus (Gram positive) and E. coli (Gram negative). Nearly all the crude serial extraction fractions contained compounds that inhibited the growth of E. coli. The hexane extract had the most lines of inhibition followed by ethyl acetate. Bioassay-guided fractionation against E. coli was used to isolate antibacterial compounds. The largest number of antibacterial compounds occurred in the hexane fraction. Furthermore we tried to complete the characterization by extracting and studying other biologically important plant metabolites such as phenolic compounds to evaluate the antioxidant capacity of Rosmarinus extracts
- Full Text:
- Date Issued: 2008
- Authors: Okoh, Omobola Oluranti
- Date: 2008
- Subjects: Calendula (Genus) , Essences and essential oils , Medicinal plants , Calendula officinalis
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11334 , http://hdl.handle.net/10353/d1001150 , Calendula (Genus) , Essences and essential oils , Medicinal plants , Calendula officinalis
- Description: Variations in the yield, chemical composition, antibacterial, and antioxidant properties of the essential oils of Rosmarinus officinalis L. cultivated in Alice, Eastern Cape of South Africa over a period of 12 months using the solvent-free microwave extraction and traditional hydrodistillation methods were evaluated. The GC-MS analyses of the essential oils revealed the presence of 33 compounds with 1,8-cineole, a-pinene, camphor, verbenone, bornyl acetate and camphene constituting about 80 percent of the oils throughout the period of investigation, with the solvent-free microwave extraction method generally yielding more of the major components than the hydrodistillation method. Each of the major components of the oils varied in quantity and quality of yield at different periods of the year. The method of extraction and time of harvest are of importance to the quantity and quality of essential oil of Rosmarinus officinalis. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene- 4-ol, linalool, a-terpeneol were present in the oil of SFME in comparison with HD. However, HD oil contained more monoterpene hydrocarbons such as a-pinene, camphene, β-pinene, myrcene, a-phellanderene, 1,8-cineole, trans- β-ocimene, γ-teprinene, and cis-sabinene hydrate than SFME extracted oil. Accumulation of monoterpene alcohols and ketones was observed during maturation process of Rosmarinus leaves. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration values were determined using a serial microplate dilution method. The essential oils obtained using both methods of extraction were active against all the bacteria tested at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the SFME extracted oils ranged between 0.23 and 1.88 mg mL-1, while those of the HD extracted oils varied between 0.94 and 7.5 mg mL-1, thus suggesting that the oil obtained by solvent free microwave extraction was more active against bacteria than the oil obtained through hydrodistillation. The antioxidant and free radical scavenging activity of the obtained oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay and β- carotene bleaching test. In the DPPH+ assay, while the free radical scavenging activity of the oil obtained by SFME method showed percentage inhibitions of between 48.8 percent and 67 percent, the HD derived oil showed inhibitions of between 52.2 percent and 65.30 percent at concentrations of 0.33, 0.50 and 1.0 mg mL-1, respectively. In the β-carotene bleaching assay, the percentage inhibition increased with increasing concentration of both oils with a higher antioxidant activity of the oil obtained through the SFME than the HD method. Thin layer chromatography (TLC) was used to analyze the chemical composition of the extracts using three eluent solvent systems of varying polarities i. e. CEF, BEA and EMW and sprayed with vanillin-sulfuric acid. The chemical composition of the different extracts was similar with the exception of methanol and water extracts which had only one or two visible compounds after treating with vanillin-spray reagent. To evaluate the number of antibacterial compounds present in the fractions, bioautography was used against two most important nosocomial microorganisms. S. aureus (Gram positive) and E. coli (Gram negative). Nearly all the crude serial extraction fractions contained compounds that inhibited the growth of E. coli. The hexane extract had the most lines of inhibition followed by ethyl acetate. Bioassay-guided fractionation against E. coli was used to isolate antibacterial compounds. The largest number of antibacterial compounds occurred in the hexane fraction. Furthermore we tried to complete the characterization by extracting and studying other biologically important plant metabolites such as phenolic compounds to evaluate the antioxidant capacity of Rosmarinus extracts
- Full Text:
- Date Issued: 2008
Antibacterial properties of the methanol extract of helichrysum pedunculatum
- Authors: Ncube, Nqobile S
- Date: 2008
- Subjects: Medicinal plants , Methanol , Helichrysum
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11241 , http://hdl.handle.net/10353/461 , Medicinal plants , Methanol , Helichrysum
- Description: The methanol extract of Helichrisum pedunculatum was screened for antimicrobial activity up to a concentration of 5 mg/ml using the agar dilution technique. A number of test bacterial isolates, comprising both Gram negative and Gram positive organisms were susceptible to the crude extract of the plant. The minimum inhibitory concentrations (MICs) of the extract ranged between 1 and 5 mg/ml for the susceptible organisms. The MICs of the selected antibiotics, chloramphenicol and penicillin, ranged between 2 and 4 mg/L, and 2 and 32 mg/L respectively against Bacillus cereus, Proteus vulgaris and Staphylococcus aureus OKOH1. Bactericidal activity was determined by the time kill assay. The methanol extract of the plant was not bactericidal at 1 × MIC for B. cereus, P. vulgaris and Staph. aureus OKOH1. At 2 × MIC the extract was bacteriostatic against B. cereus but bactericidal against P. vulgaris and Staph. aureus OKOH1. Combination studies were done at 1/2 × MIC, 1 × MIC and 2 × MIC of the plant extract with 1 × MIC of the antibiotics. Combinations of the plant extract and chloramphenicol resulted in mostly indifferent interactions against P. vulgaris and Staph. aureus OKOH1 but synergistic interactions at higher concentration of the plant extract for B. cereus. Penicillin combinations gave synergistic interactions at lower concentrations of the plant for P.vulgaris and Staph. aureus OKOH1 but was mostly indifferent for B. cereus.
- Full Text:
- Date Issued: 2008
- Authors: Ncube, Nqobile S
- Date: 2008
- Subjects: Medicinal plants , Methanol , Helichrysum
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11241 , http://hdl.handle.net/10353/461 , Medicinal plants , Methanol , Helichrysum
- Description: The methanol extract of Helichrisum pedunculatum was screened for antimicrobial activity up to a concentration of 5 mg/ml using the agar dilution technique. A number of test bacterial isolates, comprising both Gram negative and Gram positive organisms were susceptible to the crude extract of the plant. The minimum inhibitory concentrations (MICs) of the extract ranged between 1 and 5 mg/ml for the susceptible organisms. The MICs of the selected antibiotics, chloramphenicol and penicillin, ranged between 2 and 4 mg/L, and 2 and 32 mg/L respectively against Bacillus cereus, Proteus vulgaris and Staphylococcus aureus OKOH1. Bactericidal activity was determined by the time kill assay. The methanol extract of the plant was not bactericidal at 1 × MIC for B. cereus, P. vulgaris and Staph. aureus OKOH1. At 2 × MIC the extract was bacteriostatic against B. cereus but bactericidal against P. vulgaris and Staph. aureus OKOH1. Combination studies were done at 1/2 × MIC, 1 × MIC and 2 × MIC of the plant extract with 1 × MIC of the antibiotics. Combinations of the plant extract and chloramphenicol resulted in mostly indifferent interactions against P. vulgaris and Staph. aureus OKOH1 but synergistic interactions at higher concentration of the plant extract for B. cereus. Penicillin combinations gave synergistic interactions at lower concentrations of the plant for P.vulgaris and Staph. aureus OKOH1 but was mostly indifferent for B. cereus.
- Full Text:
- Date Issued: 2008
African traditional medicine-antiretroviral interactions : effects of Sutherlandia frutescens on the pharmacokinetics of Atazanavir
- Authors: Müller, Adrienne Carmel
- Date: 2011 , 2011-03-28
- Subjects: Antiretroviral agents , Medicinal plants , Traditional medicine , AIDS (Disease) -- Treatment , HIV infections -- Drug therapy , Drug interactions , Pharmacokinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3859 , http://hdl.handle.net/10962/d1013373
- Description: In response to the urgent call for investigations into antiretroviral (ARV)-African traditional medicine (ATM) interactions, this research was undertaken to ascertain whether chronic administration of the ATM, Sutherlandia frutescens (SF) may alter the bioavailability of the protease inhibitor (PI), atazanavir (ATV), which may impact on the safety or efficacy of the ARV. Prior to investigating a potential interaction between ATV and SF in vitro and in vivo, a high performance liquid chromatography method with ultraviolet detection (HPLC-UV) was developed and validated for the bioanalysis of ATV in human plasma and liver microsomes. An improved and efficient analytical method with minimal use of solvents and short run time was achieved in comparison to methods published in the literature. In addition, the method was selective, linear, accurate and precise for quantitative analysis of ATV in these studies. Molecular docking studies were conducted to compare the binding modes and affinities of ATV and two major SF constituents, Sutherlandioside B and Sutherlandin C, with the efflux transporter, P-glycoprotein (P-gp) and the CYP450 isoenzyme, CYP3A4 to determine the potential for these phytochemicals to competitively inhibit the binding of ATV to these two proteins, which are mediators of absorption and metabolism. These studies revealed that modulation of P-gp transport of ATV by Sutherlandioside B and Sutherlandin C was not likely to occur via competitive inhibition. The results further indicated that weak competitive inhibition of CYP3A4 may possibly occur in the presence of either of these two SF constituents. The Caco-2 cell line was used as an in vitro model of human intestinal absorption. Accumulation studies in these cells were conducted to ascertain whether extracts and constituents of SF have the ability to alter the absorption of ATV. The results showed that the aqueous extract of SF significantly reduced ATV accumulation, suggesting decreased ATV absorption, whilst a triterpenoid glycoside fraction isolated from SF exhibited an opposing effect. Analogous responses were elicited by the aqueous extract and a triterpenoid glycoside fraction in similar accumulation studies in P-gp overexpressing Madin–Darby Canine Kidney Strain II cells (MDCKII-MDR1), which signified that the effects of this extract and component on ATV transport in the Caco-2 cells were P-gp-mediated. The quantitative analysis of ATV in human liver microsomes after co-incubation with extracts and components of SF was conducted to determine the effects of SF on the metabolism of ATV. The aqueous and methanolic extracts of SF inhibited ATV metabolism, whilst the triterpenoid glycoside fraction had a converse effect. Analogous effects by the extracts were demonstrated in experiments conducted in CYP3A4-transfected microsomes, suggesting that the inhibition of ATV metabolism in the liver microsomes by these SF extracts was CYP3A4-mediated. A combination of Sutherlandiosides C and D also inhibited CYP3A4-mediated ATV metabolism, which was in contrast to the response elicited by the triterpenoid fraction in the liver microsomes, where other unidentified compounds, shown to be present therein, may have contributed to the activation of ATV metabolism. The in vitro studies revealed the potential for SF to alter the bioavailability of ATV, therefore a clinical study in which the effect of a multiple dose regimen of SF on the pharmacokinetics (PK) of a single dose of ATV was conducted in healthy male volunteers. The statistical analysis showed that the 90 % confidence intervals around the geometric mean ratios (ATV + SF/ATV alone) for both Cmax and AUC0-24 hours, fell well below the lower limit of the "no-effect" boundary of 0.8 – 1.25, implying that the bioavailability of ATV was significantly reduced in this cohort of subjects. It may thus be concluded that if the reduction in bioavailability observed in this clinical study is found to be clinically relevant, co-administration of SF commercial dosage forms and ATV in HIV/AIDS patients may potentially result in subtherapeutic ATV levels, which may in turn contribute to ATV resistance and/or treatment failure. This research has therefore highlighted the potential risk for toxicity or lack of efficacy of ARV regimens which may result when ATMs and PIs are used concurrently and that patients and health care practitioners alike should be aware of these perils.
- Full Text:
- Date Issued: 2011
- Authors: Müller, Adrienne Carmel
- Date: 2011 , 2011-03-28
- Subjects: Antiretroviral agents , Medicinal plants , Traditional medicine , AIDS (Disease) -- Treatment , HIV infections -- Drug therapy , Drug interactions , Pharmacokinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3859 , http://hdl.handle.net/10962/d1013373
- Description: In response to the urgent call for investigations into antiretroviral (ARV)-African traditional medicine (ATM) interactions, this research was undertaken to ascertain whether chronic administration of the ATM, Sutherlandia frutescens (SF) may alter the bioavailability of the protease inhibitor (PI), atazanavir (ATV), which may impact on the safety or efficacy of the ARV. Prior to investigating a potential interaction between ATV and SF in vitro and in vivo, a high performance liquid chromatography method with ultraviolet detection (HPLC-UV) was developed and validated for the bioanalysis of ATV in human plasma and liver microsomes. An improved and efficient analytical method with minimal use of solvents and short run time was achieved in comparison to methods published in the literature. In addition, the method was selective, linear, accurate and precise for quantitative analysis of ATV in these studies. Molecular docking studies were conducted to compare the binding modes and affinities of ATV and two major SF constituents, Sutherlandioside B and Sutherlandin C, with the efflux transporter, P-glycoprotein (P-gp) and the CYP450 isoenzyme, CYP3A4 to determine the potential for these phytochemicals to competitively inhibit the binding of ATV to these two proteins, which are mediators of absorption and metabolism. These studies revealed that modulation of P-gp transport of ATV by Sutherlandioside B and Sutherlandin C was not likely to occur via competitive inhibition. The results further indicated that weak competitive inhibition of CYP3A4 may possibly occur in the presence of either of these two SF constituents. The Caco-2 cell line was used as an in vitro model of human intestinal absorption. Accumulation studies in these cells were conducted to ascertain whether extracts and constituents of SF have the ability to alter the absorption of ATV. The results showed that the aqueous extract of SF significantly reduced ATV accumulation, suggesting decreased ATV absorption, whilst a triterpenoid glycoside fraction isolated from SF exhibited an opposing effect. Analogous responses were elicited by the aqueous extract and a triterpenoid glycoside fraction in similar accumulation studies in P-gp overexpressing Madin–Darby Canine Kidney Strain II cells (MDCKII-MDR1), which signified that the effects of this extract and component on ATV transport in the Caco-2 cells were P-gp-mediated. The quantitative analysis of ATV in human liver microsomes after co-incubation with extracts and components of SF was conducted to determine the effects of SF on the metabolism of ATV. The aqueous and methanolic extracts of SF inhibited ATV metabolism, whilst the triterpenoid glycoside fraction had a converse effect. Analogous effects by the extracts were demonstrated in experiments conducted in CYP3A4-transfected microsomes, suggesting that the inhibition of ATV metabolism in the liver microsomes by these SF extracts was CYP3A4-mediated. A combination of Sutherlandiosides C and D also inhibited CYP3A4-mediated ATV metabolism, which was in contrast to the response elicited by the triterpenoid fraction in the liver microsomes, where other unidentified compounds, shown to be present therein, may have contributed to the activation of ATV metabolism. The in vitro studies revealed the potential for SF to alter the bioavailability of ATV, therefore a clinical study in which the effect of a multiple dose regimen of SF on the pharmacokinetics (PK) of a single dose of ATV was conducted in healthy male volunteers. The statistical analysis showed that the 90 % confidence intervals around the geometric mean ratios (ATV + SF/ATV alone) for both Cmax and AUC0-24 hours, fell well below the lower limit of the "no-effect" boundary of 0.8 – 1.25, implying that the bioavailability of ATV was significantly reduced in this cohort of subjects. It may thus be concluded that if the reduction in bioavailability observed in this clinical study is found to be clinically relevant, co-administration of SF commercial dosage forms and ATV in HIV/AIDS patients may potentially result in subtherapeutic ATV levels, which may in turn contribute to ATV resistance and/or treatment failure. This research has therefore highlighted the potential risk for toxicity or lack of efficacy of ARV regimens which may result when ATMs and PIs are used concurrently and that patients and health care practitioners alike should be aware of these perils.
- Full Text:
- Date Issued: 2011
Medicinal properties of Moringa (Moringa Oleifera Lam) leaves and the effect of its use as a supplement on goat growth performance and meat characteristics
- Moyo, Busani https://orcid.org/0000-0001-7002-7266
- Authors: Moyo, Busani https://orcid.org/0000-0001-7002-7266
- Date: 2011-09
- Subjects: Moringa , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24376 , vital:62662
- Description: The main objective of the study was to determine if feeding goats with Moringa oleifera leaves would lead to an increase in productivity and in value of the meat. The proximate, van Soet, atomic absorption spectrophotometric and soxhlet extraction methods were used to determine the nutritional value M. oleifera leaves of the South African. The in-vitro antimicrobial screening methods were used to determine antimicrobial activities M. oleifera extracts while in vitro and invivo models were used to determine the antioxidant activities of M. oleifera leaves. An evaluation of the potential of M. oleifera leaf meal as a feed supplement in terms of its effect on helminth load, goat growth performance, carcass characteristics, meat quality attributes, nutritional and consumer sensory characteristics of goat meat was done. A total of 24, eight month old goats were randomly allocated to dietary treatments of M. oleifera leaf meal (MOL), sunflower seed cake (SC) and GH (grass hay) which was the control. All the groups were fed on basal diet of grass hay ad libitum and 200g wheat bran per head per day. The MOL group was given an additional 200 g of dried M. oleifera leaves while the SC group was offered 170 g sunflower seed cake per head/day. The study showed that the dried leaves had crude protein levels of 30.3 percent, polyunsaturated fatty acids (52.21 percent), Saturated fatty acids (43.31), n-3 (44.57 percent), n-6 (7.64 percent), 19 amino acids, vitamin E (77 mg/100 g) and Beta-carotene (18.5 mg/100 g). The M. oleifera leaf extracts showed antibacterial activities against Escherichia coli, Enterobacter cloace, Proteus vulgaris, Staphylococcus aureus and Micrococcus kristinae. The supplementation of goats with MOL and SC resulted in decreased feacal larval count and lower Haemonchus contortus, Trichostrongylus colubriforms and Oesophagastum columbianum worm burdens than those in the non-supplemented goats. Goats supplemented with SC and MOL had higher average daily weight gain and heavier carcasses than those in the GH group. Higher pH1 scores were observed in chevon from GH diet than the supplemented ones. The MOL and SC supplemented goats had chevon with higher values for lightness (L*) 24 hr post-mortem than the one from the GH group. The redness (a*) values of chevon 24 hr post mortem was highest in MOL supplemented goats. Warner Bratzler shear force (WBSF) values of SC (30.1 N) and MOL (29.8 N) supplemented goats were lower than those from GH diet (32.6 N). Chevon from goats fed GH diet had significantly higher cooking losses (29.5 percent) than that from MOL (25.4 percent) and SC (25.6 percent) fed groups. It was observed that chevon from MOL and SC supplemented groups had higher crude protein (23.57 and 22.95 percent, respectively) than the one from the GH group (21.20 percent). Cholesterol levels were higher in chevon from SC (42.84) supplemented goats than those from MOL (38.76) and GH (35.63 mg). Chevon from GH and MOL group had higher (P < 0.05) proportions of PUFA, n-3, PUFA/SFA ratio and lower n-6/n-3 ratio. Mean consumer scores for first bite, aroma, flavour and juiceness were higher in the MOL group than in the GH group (P < 0.05). The acetone extract exhibited higher concentrations of total flavonoids, flavonols, phenolics. The acetone extracts depicted higher percentage inhibition against DPPH, ABTS and nitric oxide radicals which were comparable with reference antioxidant (vitamin C and BHT). The M. oleifera leaf meal increased the antioxidant activity of GSH, SOD and catalase. Moringa oleifera leaves also exhibited medicinal properties by having anthelmintic, antibacterial activities and showed antioxidant properties. It was also observed that protein supplementation improved the animal growth performance, the physico-chemical characteristics, nutritional and fatty acids composition of meat hence meeting the consumer needs. , Thesis (PhD) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Date Issued: 2011-09
- Authors: Moyo, Busani https://orcid.org/0000-0001-7002-7266
- Date: 2011-09
- Subjects: Moringa , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24376 , vital:62662
- Description: The main objective of the study was to determine if feeding goats with Moringa oleifera leaves would lead to an increase in productivity and in value of the meat. The proximate, van Soet, atomic absorption spectrophotometric and soxhlet extraction methods were used to determine the nutritional value M. oleifera leaves of the South African. The in-vitro antimicrobial screening methods were used to determine antimicrobial activities M. oleifera extracts while in vitro and invivo models were used to determine the antioxidant activities of M. oleifera leaves. An evaluation of the potential of M. oleifera leaf meal as a feed supplement in terms of its effect on helminth load, goat growth performance, carcass characteristics, meat quality attributes, nutritional and consumer sensory characteristics of goat meat was done. A total of 24, eight month old goats were randomly allocated to dietary treatments of M. oleifera leaf meal (MOL), sunflower seed cake (SC) and GH (grass hay) which was the control. All the groups were fed on basal diet of grass hay ad libitum and 200g wheat bran per head per day. The MOL group was given an additional 200 g of dried M. oleifera leaves while the SC group was offered 170 g sunflower seed cake per head/day. The study showed that the dried leaves had crude protein levels of 30.3 percent, polyunsaturated fatty acids (52.21 percent), Saturated fatty acids (43.31), n-3 (44.57 percent), n-6 (7.64 percent), 19 amino acids, vitamin E (77 mg/100 g) and Beta-carotene (18.5 mg/100 g). The M. oleifera leaf extracts showed antibacterial activities against Escherichia coli, Enterobacter cloace, Proteus vulgaris, Staphylococcus aureus and Micrococcus kristinae. The supplementation of goats with MOL and SC resulted in decreased feacal larval count and lower Haemonchus contortus, Trichostrongylus colubriforms and Oesophagastum columbianum worm burdens than those in the non-supplemented goats. Goats supplemented with SC and MOL had higher average daily weight gain and heavier carcasses than those in the GH group. Higher pH1 scores were observed in chevon from GH diet than the supplemented ones. The MOL and SC supplemented goats had chevon with higher values for lightness (L*) 24 hr post-mortem than the one from the GH group. The redness (a*) values of chevon 24 hr post mortem was highest in MOL supplemented goats. Warner Bratzler shear force (WBSF) values of SC (30.1 N) and MOL (29.8 N) supplemented goats were lower than those from GH diet (32.6 N). Chevon from goats fed GH diet had significantly higher cooking losses (29.5 percent) than that from MOL (25.4 percent) and SC (25.6 percent) fed groups. It was observed that chevon from MOL and SC supplemented groups had higher crude protein (23.57 and 22.95 percent, respectively) than the one from the GH group (21.20 percent). Cholesterol levels were higher in chevon from SC (42.84) supplemented goats than those from MOL (38.76) and GH (35.63 mg). Chevon from GH and MOL group had higher (P < 0.05) proportions of PUFA, n-3, PUFA/SFA ratio and lower n-6/n-3 ratio. Mean consumer scores for first bite, aroma, flavour and juiceness were higher in the MOL group than in the GH group (P < 0.05). The acetone extract exhibited higher concentrations of total flavonoids, flavonols, phenolics. The acetone extracts depicted higher percentage inhibition against DPPH, ABTS and nitric oxide radicals which were comparable with reference antioxidant (vitamin C and BHT). The M. oleifera leaf meal increased the antioxidant activity of GSH, SOD and catalase. Moringa oleifera leaves also exhibited medicinal properties by having anthelmintic, antibacterial activities and showed antioxidant properties. It was also observed that protein supplementation improved the animal growth performance, the physico-chemical characteristics, nutritional and fatty acids composition of meat hence meeting the consumer needs. , Thesis (PhD) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Date Issued: 2011-09
Molecular characterization, antibiograms and activity of medicinal plants against streptococcus pneumoniae and haemophilus influenzae isolates from clinical samples of patients in the Eastern Cape province, South Africa
- Authors: Morobe, Isaac Christopher
- Date: 2015-00
- Subjects: Medicinal plants
- Language: English
- Type: Master's/Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6469 , vital:46340
- Description: H. influenzae and S. pneumoniae are important causes of community acquired respiratory tract infections including, pneumonia, acute sinusitis, otitis media, meningitis, bacteremia, sepsis, osteomyelitis, pericarditis, septic arthritis, endocarditis, peritonitis, cellulitis and brain abscesses. The ability to effectively treat bacterial infections has been compromised in recent years due to the acquisition of antibiotic resistance, particularly to β-lactam drugs. The increasing trends in antibiotic resistance have prompted incessant searches aimed at unraveling new effective sources for the management of microbial infections. Plant derived antimicrobial compounds that have no or minimal toxicity to host cells are considered candidates for developing new antimicrobial drugs. Safety is therefore critical in the development and formulation of such antimicrobials. In addition to studies on the structural elucidation of active compounds of selected medicinal plants and determination of their toxicity levels, concerted investigations on the molecular landscape of the designated bacteria, including genes coding for resistance and virulence, the phylogenetic profiles of isolates from different sources and the abilities of isolates to withstand the normal bactericidal activities of human serum samples from different blood groups are critical for a thorough understanding of the management, pathogenetic and clinico- epidemiological trajectories of the pathogens. Therefore, the aims of the various studies were to characterize local H. influenzae and S. pneumoniae isolates by serological and molecular methods; ascertain the antibiotic susceptibility profiles of isolates in order to provide updated data and guide clinicians and other health care workers on the empiric management of patients; determine genes coding for virulence and phylogenetic relatedness of isolates of H. influenzae and S. pneumoniae from diverse sources; ascertain the bactericidal activity of human serum samples from different blood groups against H. influenzae and S. pneumoniae and also to determine the activity of active compounds and toxicity levels of selected medicinal plants. In order to achieve these goals, relevant samples were collected and screened using an array of microbiological, serological, molecular and phytochemical methods, which would be espoused in the relevant chapters, presented hereunder. Key findings of the various chapters including their contributions to knowledge are highlighted. The studies are presented in eight chapters and each chapter, with the exception of chapter one (General Introduction and Literature Review) consists of an introduction, materials and methods, results, discussions, conclusions and references. Each chapter is therefore designed as a publishable unit. Chapter 1 gives an account of the background to the study and the literature review. The morphology, cultural characteristics, laboratory diagnosis, pathogenesis, antibiogram and clinical manifestations of H. influenzae and S. pneumoniae were reviewed. Furthermore, the activities of medicinal plants and their various applications in the management of infections in different countries, including their possible active compounds and toxicity levels were also explored in order to provide a suitable background for the study. Similar reviews were undertaken for molecular aspects of both pathogens as well as the activities of human serum samples against microbial infections. In Chapter 2 the prevalence and antibiotic resistance profiles of H. influenzae and, S. pneumoniae isolates from clinical samples of patients in Mthatha, Eastern Cape Province were investigated. Clinical samples were obtained randomly from individuals attending different hospitals in Mthatha district. Samples were analysed using the Kirby Bauer disk diffusion test (antibiotic susceptibility testing) and MIC breakpoints were determined using E-test strips. From a total of 475 clinical samples tested, 323 (68.0%) were positive for both H. influenzae and S. pneumoniae. Most of the positive isolates were obtained from children under 9 years. Out of 323 isolates, 187 (57.89%) were positive for H. influenzae and 136 (42.1%) were positive for S. pneumoniae. From 10 hospitals selected for sampling in this study, Mthatha General Hospital recorded the highest number of isolates, 42 (25.15%) and 31 (22.79%) of H. influenzae and S. pneumoniae positive isolates respectively, followed by Nelson Mandela Academic Hospital 33 (19.76%) and 26 (19.12%) respectively while ST. Patricks 8 (4.79%) recorded the least number of isolates for H. influenzae and Khotsong 4 (2.94%) recorded the least number of isolates for S. pneumoniae. Antibiotic susceptibility tests revealed Amoxicillin (MIC50, 0.125μg/ml) and Vancomycin (MIC50,0.12μg/ml) as the most effective antibiotics against S. pneumoniae isolates and Co-amoxiclav (MIC50,0.3µg/ml) and Cefuroxime (MIC50,0.15µg/ml) against H. influenzae isolates. These data highlight the need for education and to consider predominant resistance when choosing empiric therapies to treat bacterial infections. Chapter 3 was designed to investigate the virulence factors of H. influenzae and S. pneumoniae isolates from clinical specimens of patients with respiratory tract infections in Mthatha district, the Eastern Cape Province. PCR and sequencing methods were used to verify the genetic determinants responsible for virulence in H. influenzae and S. pneumoniae strains. Results indicated that, of the 187 H. influenzae isolates studied, 26 (13.9%) were typeable, positive by genotypic determination, while 161 (86.1%) were non typeable (NTHi) strains. On the other, out of the 136 S. pneumoniae isolates 24 (17.6%) were typeable while 112 (82.4%) were non typeable strains. All isolates tested contained the metS2 gene for both H. influenzae and S. pneumoniae. The phylogenetic clusters identified by maximum-parsimony analysis were also compared to the results of 16S rRNA sequences. Twenty five percent of none typeable strains were typed by 16S rRNA sequencing. The phylogenetic tree yielded 7.7% H. influenzae similarities while S. pneumoniae yielded 25% similarities with other typeable strains. The presence of genes coding for virulence in this study suggest a significant contribution of genes encoding for virulence to antimicrobial resistance among respiratory tract organisms studied. This study underlines the importance of understanding the virulence composition and diversity of pathogens for enhanced clinico-epidemiological monitoring and health care delivery. The findings will also provide a genetic foundation for future research into mechanisms of pathogenesis of H. influenzae and S. pneumoniae and may accelerate the development of safe and effective vaccines to prevent and control diseases caused by H. influenzae and S. pneumoniae. In Chapter 4, cytotoxic effects and safety profiles of extracts of active medicinal plants from the OR Tambo District Municipality in the Eastern Cape of South Africa were carried out. The most prominent families of medicinal plants (Solanacea and Euphorbiaceae) were used. Extracts of nine South African medicinal plants were screened for cytotoxic activities against MAGI CC5+ cells using MTT assay. Results indicated that nine plant extracts (methanolic and aqueous) used in the MTT assay revealed Herb 2 (Cyanthula inculata) as the most potent extract identified with activity of 1.4 Cc50 values of 25.6 mg/mL and induced over 50% of cell deaths, followed by herb 3 (Croton grattismus) and Herb 4 (Cassine trasvaalensis) with activity of 0.2 Cc50 values of 3.7 mg/mL each. The herbs that induced the least cell death, were herbs 5 (Capris tomentosa) and 7 (Hypoxis hemerocallidea), with the activity of 0.05 Cc50 values of 0.9 mg/mL each. Of the nine plant extracts 2(22%) exhibited minimal toxicity on MAGI cells and 7(77.8%) exhibited 50% toxicity. Two (22%) of the methanolic extracts exhibited anti-HIV1 IIIB activities and against Mycobacterium tuberculosis (TB) only one medicinal plant extract (Lysium inerme) exhibited 29% activity. Cytotoxicity tests will provide comprehensive reference data bases for the profiling and eventual considerations of medicinal plants as potential templates for drug designs and medical applications. In chapter 5 Chemical Components of the volatile and non-volatile extractives of Croton species and their microbial activities were screened. Isolation of the essential oils from the leaves of Croton pseudopulchellus and C. gratissimus from the Eastern Cape and KwaZulu-Natal Provinces in South Africa were performed using an all glass Clevenger apparatus according to the British Pharmacopeia method. The minimum inhibitory concentrations of the oils were assessed against the seven different standard strains of bacteria: H. influenzae, Bacillus pimitus, Staphylococcus aureus, S. pneumoniae, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens and Entarobacter cloacae using micro dilution technique on a 96 well microtitre plate. Results showed golden to very light yellow oils obtained with percentage yield of 1.03 -1.25 respectively (w/w). Analysis of the oils was performed using Gas Chromatography and Gas Chromatography/Mass Spectrophotometry. The leaf oil of Croton pseudopulchellus had germacrene (24.2%),β-phellandrene (17.4%), myrcene (13.4%) and β-caryophyllene (11.4%) as the prominent compounds identified in the oil. The chemical composition of the leaf oil of C. gratissimus was characterized by sabinene (14.6%), β-phellandrene (12.3%), α-phellandrene (10.7%), α-pinene (6.0%) and germacrene D (5.9%). Chemical profiles of the essential oils of Croton species reported in literatures are specific to their geographical location. The oils from C. pseudopulchellus and C. grattisimus were found to have significant antibacterial activities and therefore could be used as natural antimicrobial agents for the treatment of several infectious diseases caused by pathogenic and antibiotic resistant organisms. Chapters 6 and 7 were designed to isolate two bioactive compounds from the stem bark of Lycium inerme and the leaves of Croton grattisimus and were screened for their biological activities against H. influenzae and S. pneumoniae. A qualitative phytochemical screening and bioassay of the plants extracts was carried out. Antimicrobial screening was by broth microdilution and bioautography. Bioassay results showed that compounds with Rf –values between 0.67 to 0.80 were very active against H. influenzae and S. pneumoniae. However, the most active of these compounds was observed at 0.70 for H. influenzae and 0.69 for S. pneumoniae from the dichloromethane extract. Column chromatography, Preparative Thin Layer Chromatography (PTLC) and Sephadex LH20 were used for isolation, sample clean-up and purification of this extract. Two active compounds: a coumarin (7-hydroxy-6-methoxy-coumarin) and two triterpenoids, Ursolic acid (3-oxo-19-hydroxyl-6-methoxylpomolic acid) and Moronic acid (3-oxoolean-12-en-28-oic acid) were isolated from the dichloromethane fraction. The presence of Coumarins and Terpenoids in this herb was observed from the TLC fingerprints. NMR spectroscopic methods were used for the structural elucidation of the active compounds while the GC-MS was used to determine the presence of essential oils from volatile samples obtained from the leaves of C. grattisimus and L. inerme. C. grattisimus extracts possess strong free radicals with scavenging, antimicrobial and antifungal activities; therefore, further studies are needed to determine their efficacies in vivo or clinical usefulness. L. inerme stem bark can therefore be used as a source of alternative medicine or new pharmaceutical and health care product or as a starting material for synthesis of drugs. In chapter 8, general conclusions and perspectives of various parts of the findings were captured. The multi-drug resistance was observed among the emerging respiratory tract bacterial pathogens. It was recommended that measures should be put in place to control the spread of drug resistance in pathogens through improved and standardized laboratory practices, proper and regular surveillance to help guide against the indiscriminate use of antibiotics in empirical treatment. The recognition but cautious use of medicinal plants as alternative sources of therapies and a probable means to solve the emerging resistance problem was recommended. Improved standard of hygiene in hospital settings and the communities is important to prevent the spread of infections. The thesis provides a novel reference document on the genes coding for resistance, antibiograms and phylogenetic profiles of local isolates of H. influenzae and S. pneumoniae as well as the activities, active compounds and toxicity levels of medicinal plants investigated in an endeavour to effectively understand the possible therapeutic, molecular and epidemiological trends in respect of the designated pathogens. , Thesis (Phd) -- Faculty of Health Sciences, 2015
- Full Text:
- Date Issued: 2015-00
- Authors: Morobe, Isaac Christopher
- Date: 2015-00
- Subjects: Medicinal plants
- Language: English
- Type: Master's/Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6469 , vital:46340
- Description: H. influenzae and S. pneumoniae are important causes of community acquired respiratory tract infections including, pneumonia, acute sinusitis, otitis media, meningitis, bacteremia, sepsis, osteomyelitis, pericarditis, septic arthritis, endocarditis, peritonitis, cellulitis and brain abscesses. The ability to effectively treat bacterial infections has been compromised in recent years due to the acquisition of antibiotic resistance, particularly to β-lactam drugs. The increasing trends in antibiotic resistance have prompted incessant searches aimed at unraveling new effective sources for the management of microbial infections. Plant derived antimicrobial compounds that have no or minimal toxicity to host cells are considered candidates for developing new antimicrobial drugs. Safety is therefore critical in the development and formulation of such antimicrobials. In addition to studies on the structural elucidation of active compounds of selected medicinal plants and determination of their toxicity levels, concerted investigations on the molecular landscape of the designated bacteria, including genes coding for resistance and virulence, the phylogenetic profiles of isolates from different sources and the abilities of isolates to withstand the normal bactericidal activities of human serum samples from different blood groups are critical for a thorough understanding of the management, pathogenetic and clinico- epidemiological trajectories of the pathogens. Therefore, the aims of the various studies were to characterize local H. influenzae and S. pneumoniae isolates by serological and molecular methods; ascertain the antibiotic susceptibility profiles of isolates in order to provide updated data and guide clinicians and other health care workers on the empiric management of patients; determine genes coding for virulence and phylogenetic relatedness of isolates of H. influenzae and S. pneumoniae from diverse sources; ascertain the bactericidal activity of human serum samples from different blood groups against H. influenzae and S. pneumoniae and also to determine the activity of active compounds and toxicity levels of selected medicinal plants. In order to achieve these goals, relevant samples were collected and screened using an array of microbiological, serological, molecular and phytochemical methods, which would be espoused in the relevant chapters, presented hereunder. Key findings of the various chapters including their contributions to knowledge are highlighted. The studies are presented in eight chapters and each chapter, with the exception of chapter one (General Introduction and Literature Review) consists of an introduction, materials and methods, results, discussions, conclusions and references. Each chapter is therefore designed as a publishable unit. Chapter 1 gives an account of the background to the study and the literature review. The morphology, cultural characteristics, laboratory diagnosis, pathogenesis, antibiogram and clinical manifestations of H. influenzae and S. pneumoniae were reviewed. Furthermore, the activities of medicinal plants and their various applications in the management of infections in different countries, including their possible active compounds and toxicity levels were also explored in order to provide a suitable background for the study. Similar reviews were undertaken for molecular aspects of both pathogens as well as the activities of human serum samples against microbial infections. In Chapter 2 the prevalence and antibiotic resistance profiles of H. influenzae and, S. pneumoniae isolates from clinical samples of patients in Mthatha, Eastern Cape Province were investigated. Clinical samples were obtained randomly from individuals attending different hospitals in Mthatha district. Samples were analysed using the Kirby Bauer disk diffusion test (antibiotic susceptibility testing) and MIC breakpoints were determined using E-test strips. From a total of 475 clinical samples tested, 323 (68.0%) were positive for both H. influenzae and S. pneumoniae. Most of the positive isolates were obtained from children under 9 years. Out of 323 isolates, 187 (57.89%) were positive for H. influenzae and 136 (42.1%) were positive for S. pneumoniae. From 10 hospitals selected for sampling in this study, Mthatha General Hospital recorded the highest number of isolates, 42 (25.15%) and 31 (22.79%) of H. influenzae and S. pneumoniae positive isolates respectively, followed by Nelson Mandela Academic Hospital 33 (19.76%) and 26 (19.12%) respectively while ST. Patricks 8 (4.79%) recorded the least number of isolates for H. influenzae and Khotsong 4 (2.94%) recorded the least number of isolates for S. pneumoniae. Antibiotic susceptibility tests revealed Amoxicillin (MIC50, 0.125μg/ml) and Vancomycin (MIC50,0.12μg/ml) as the most effective antibiotics against S. pneumoniae isolates and Co-amoxiclav (MIC50,0.3µg/ml) and Cefuroxime (MIC50,0.15µg/ml) against H. influenzae isolates. These data highlight the need for education and to consider predominant resistance when choosing empiric therapies to treat bacterial infections. Chapter 3 was designed to investigate the virulence factors of H. influenzae and S. pneumoniae isolates from clinical specimens of patients with respiratory tract infections in Mthatha district, the Eastern Cape Province. PCR and sequencing methods were used to verify the genetic determinants responsible for virulence in H. influenzae and S. pneumoniae strains. Results indicated that, of the 187 H. influenzae isolates studied, 26 (13.9%) were typeable, positive by genotypic determination, while 161 (86.1%) were non typeable (NTHi) strains. On the other, out of the 136 S. pneumoniae isolates 24 (17.6%) were typeable while 112 (82.4%) were non typeable strains. All isolates tested contained the metS2 gene for both H. influenzae and S. pneumoniae. The phylogenetic clusters identified by maximum-parsimony analysis were also compared to the results of 16S rRNA sequences. Twenty five percent of none typeable strains were typed by 16S rRNA sequencing. The phylogenetic tree yielded 7.7% H. influenzae similarities while S. pneumoniae yielded 25% similarities with other typeable strains. The presence of genes coding for virulence in this study suggest a significant contribution of genes encoding for virulence to antimicrobial resistance among respiratory tract organisms studied. This study underlines the importance of understanding the virulence composition and diversity of pathogens for enhanced clinico-epidemiological monitoring and health care delivery. The findings will also provide a genetic foundation for future research into mechanisms of pathogenesis of H. influenzae and S. pneumoniae and may accelerate the development of safe and effective vaccines to prevent and control diseases caused by H. influenzae and S. pneumoniae. In Chapter 4, cytotoxic effects and safety profiles of extracts of active medicinal plants from the OR Tambo District Municipality in the Eastern Cape of South Africa were carried out. The most prominent families of medicinal plants (Solanacea and Euphorbiaceae) were used. Extracts of nine South African medicinal plants were screened for cytotoxic activities against MAGI CC5+ cells using MTT assay. Results indicated that nine plant extracts (methanolic and aqueous) used in the MTT assay revealed Herb 2 (Cyanthula inculata) as the most potent extract identified with activity of 1.4 Cc50 values of 25.6 mg/mL and induced over 50% of cell deaths, followed by herb 3 (Croton grattismus) and Herb 4 (Cassine trasvaalensis) with activity of 0.2 Cc50 values of 3.7 mg/mL each. The herbs that induced the least cell death, were herbs 5 (Capris tomentosa) and 7 (Hypoxis hemerocallidea), with the activity of 0.05 Cc50 values of 0.9 mg/mL each. Of the nine plant extracts 2(22%) exhibited minimal toxicity on MAGI cells and 7(77.8%) exhibited 50% toxicity. Two (22%) of the methanolic extracts exhibited anti-HIV1 IIIB activities and against Mycobacterium tuberculosis (TB) only one medicinal plant extract (Lysium inerme) exhibited 29% activity. Cytotoxicity tests will provide comprehensive reference data bases for the profiling and eventual considerations of medicinal plants as potential templates for drug designs and medical applications. In chapter 5 Chemical Components of the volatile and non-volatile extractives of Croton species and their microbial activities were screened. Isolation of the essential oils from the leaves of Croton pseudopulchellus and C. gratissimus from the Eastern Cape and KwaZulu-Natal Provinces in South Africa were performed using an all glass Clevenger apparatus according to the British Pharmacopeia method. The minimum inhibitory concentrations of the oils were assessed against the seven different standard strains of bacteria: H. influenzae, Bacillus pimitus, Staphylococcus aureus, S. pneumoniae, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens and Entarobacter cloacae using micro dilution technique on a 96 well microtitre plate. Results showed golden to very light yellow oils obtained with percentage yield of 1.03 -1.25 respectively (w/w). Analysis of the oils was performed using Gas Chromatography and Gas Chromatography/Mass Spectrophotometry. The leaf oil of Croton pseudopulchellus had germacrene (24.2%),β-phellandrene (17.4%), myrcene (13.4%) and β-caryophyllene (11.4%) as the prominent compounds identified in the oil. The chemical composition of the leaf oil of C. gratissimus was characterized by sabinene (14.6%), β-phellandrene (12.3%), α-phellandrene (10.7%), α-pinene (6.0%) and germacrene D (5.9%). Chemical profiles of the essential oils of Croton species reported in literatures are specific to their geographical location. The oils from C. pseudopulchellus and C. grattisimus were found to have significant antibacterial activities and therefore could be used as natural antimicrobial agents for the treatment of several infectious diseases caused by pathogenic and antibiotic resistant organisms. Chapters 6 and 7 were designed to isolate two bioactive compounds from the stem bark of Lycium inerme and the leaves of Croton grattisimus and were screened for their biological activities against H. influenzae and S. pneumoniae. A qualitative phytochemical screening and bioassay of the plants extracts was carried out. Antimicrobial screening was by broth microdilution and bioautography. Bioassay results showed that compounds with Rf –values between 0.67 to 0.80 were very active against H. influenzae and S. pneumoniae. However, the most active of these compounds was observed at 0.70 for H. influenzae and 0.69 for S. pneumoniae from the dichloromethane extract. Column chromatography, Preparative Thin Layer Chromatography (PTLC) and Sephadex LH20 were used for isolation, sample clean-up and purification of this extract. Two active compounds: a coumarin (7-hydroxy-6-methoxy-coumarin) and two triterpenoids, Ursolic acid (3-oxo-19-hydroxyl-6-methoxylpomolic acid) and Moronic acid (3-oxoolean-12-en-28-oic acid) were isolated from the dichloromethane fraction. The presence of Coumarins and Terpenoids in this herb was observed from the TLC fingerprints. NMR spectroscopic methods were used for the structural elucidation of the active compounds while the GC-MS was used to determine the presence of essential oils from volatile samples obtained from the leaves of C. grattisimus and L. inerme. C. grattisimus extracts possess strong free radicals with scavenging, antimicrobial and antifungal activities; therefore, further studies are needed to determine their efficacies in vivo or clinical usefulness. L. inerme stem bark can therefore be used as a source of alternative medicine or new pharmaceutical and health care product or as a starting material for synthesis of drugs. In chapter 8, general conclusions and perspectives of various parts of the findings were captured. The multi-drug resistance was observed among the emerging respiratory tract bacterial pathogens. It was recommended that measures should be put in place to control the spread of drug resistance in pathogens through improved and standardized laboratory practices, proper and regular surveillance to help guide against the indiscriminate use of antibiotics in empirical treatment. The recognition but cautious use of medicinal plants as alternative sources of therapies and a probable means to solve the emerging resistance problem was recommended. Improved standard of hygiene in hospital settings and the communities is important to prevent the spread of infections. The thesis provides a novel reference document on the genes coding for resistance, antibiograms and phylogenetic profiles of local isolates of H. influenzae and S. pneumoniae as well as the activities, active compounds and toxicity levels of medicinal plants investigated in an endeavour to effectively understand the possible therapeutic, molecular and epidemiological trends in respect of the designated pathogens. , Thesis (Phd) -- Faculty of Health Sciences, 2015
- Full Text:
- Date Issued: 2015-00