In vitro activity of bioactive compounds of selected South African medicinal plants on clinical isolates of Helicobacter pylori
- Authors: Okeleye, Benjamin Ifeoluwa
- Date: 2011
- Subjects: Helicobacter pylori , Microbial sensitivity tests , Traditional medicine -- South Africa , Gram-negative bacterial infections
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11255 , http://hdl.handle.net/10353/310 , Helicobacter pylori , Microbial sensitivity tests , Traditional medicine -- South Africa , Gram-negative bacterial infections
- Description: The stem bark of Peltophorum africanum and Bridelia micrantha are used in South Africa traditional medicine for treatment of intestinal parasites, relieve problems and human immunodeficiency virus/ acquired immune deficiency syndrome (HIV/AIDS). The growing problem of antibiotic resistance by Helicobacter pylori the major etiological agent in gastritis, gastric cancer, peptic and gastric ulcer demands the search for novel compounds from plant based sources. This study was aimed to determine the antimicrobial activity of five solvent (ethylacetate, acetone, ethanol, methanol and water) extracts of the stem bark of P. africanum and B. micrantha on clinical strains of H. pylori in a bid to identify potential sources of cheap starting materials for the synthesis of new drugs. H. pylori strains were isolated from patients presenting with gastric related morbidities at the Livingstone Hospital, Port Elizabeth for endoscopy and confirmed following standard microbiology procedures. The plant extracts including clarithromycin were tested against 31 clinical strains of H. pylori by the agar well diffusion method. The most potent extract was evaluated by the microdilution method to determine the Minimum Inhibitory Concentration (MIC50&90), followed by the rate of kill. Preliminary phytochemical analysis was carried out. The one way ANOVA test was used to statistically analyse the results. All the extracts demonstrated anti-H. pylori activity with zone diameters of inhibition that ranged from 0 to 23 mm for the extracts and 0 to 35 mm for clarithromycin. Marked susceptibility (100%) was recorded for the ethyl acetate extract of P. africanum (P. afr. EA) and the acetone extract of B. micrantha (B. mic. A), which were statistically significant (P < 0.05) compared to all other extracts and clarithromycin. For B. micrantha ethyl acetate extract, 93.5 percent susceptibility was observed while for the control iv antibiotic, clarithromycin it was 58.1 percent. The MIC50 ranged from 0.0048 to 0.313 mg/mL for P. afr. EA, and from 0.0048 to 0.156 mg/mL for B. mic. EA; MIC90 ranged from 0.156 mg/mL to 0.625 mg/mL and 0.0048 to 2.5 mg/mL for P. afr. EA and B. mic. EA respectively. There was a significant statistical difference observed in potency of both P. afr. EA and B. mic. A compared to the two antibiotics (P < 0.05). One hundred percent killing by P. afr EA was observed at 0.05 mg/mL (½ x MIC) and 0.2 mg/mL (2 x MIC) in 66 h for strain PE466C and PE252C respectively. For B. mic. EA, 100 percent killing effect of both strains (PE430C and PE369C) was observed at 0.1 mg/mL (2 x MIC) in 66 h. Qualitative phytochemical analysis confirmed the presence of alkaloids, flavonoids, steroids, tannins and saponins in the ethyl acetate extracts of both plants, which could be a potential template of lead molecule for the design of new anti- Helicobacter pylori therapies.
- Full Text:
- Authors: Okeleye, Benjamin Ifeoluwa
- Date: 2011
- Subjects: Helicobacter pylori , Microbial sensitivity tests , Traditional medicine -- South Africa , Gram-negative bacterial infections
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11255 , http://hdl.handle.net/10353/310 , Helicobacter pylori , Microbial sensitivity tests , Traditional medicine -- South Africa , Gram-negative bacterial infections
- Description: The stem bark of Peltophorum africanum and Bridelia micrantha are used in South Africa traditional medicine for treatment of intestinal parasites, relieve problems and human immunodeficiency virus/ acquired immune deficiency syndrome (HIV/AIDS). The growing problem of antibiotic resistance by Helicobacter pylori the major etiological agent in gastritis, gastric cancer, peptic and gastric ulcer demands the search for novel compounds from plant based sources. This study was aimed to determine the antimicrobial activity of five solvent (ethylacetate, acetone, ethanol, methanol and water) extracts of the stem bark of P. africanum and B. micrantha on clinical strains of H. pylori in a bid to identify potential sources of cheap starting materials for the synthesis of new drugs. H. pylori strains were isolated from patients presenting with gastric related morbidities at the Livingstone Hospital, Port Elizabeth for endoscopy and confirmed following standard microbiology procedures. The plant extracts including clarithromycin were tested against 31 clinical strains of H. pylori by the agar well diffusion method. The most potent extract was evaluated by the microdilution method to determine the Minimum Inhibitory Concentration (MIC50&90), followed by the rate of kill. Preliminary phytochemical analysis was carried out. The one way ANOVA test was used to statistically analyse the results. All the extracts demonstrated anti-H. pylori activity with zone diameters of inhibition that ranged from 0 to 23 mm for the extracts and 0 to 35 mm for clarithromycin. Marked susceptibility (100%) was recorded for the ethyl acetate extract of P. africanum (P. afr. EA) and the acetone extract of B. micrantha (B. mic. A), which were statistically significant (P < 0.05) compared to all other extracts and clarithromycin. For B. micrantha ethyl acetate extract, 93.5 percent susceptibility was observed while for the control iv antibiotic, clarithromycin it was 58.1 percent. The MIC50 ranged from 0.0048 to 0.313 mg/mL for P. afr. EA, and from 0.0048 to 0.156 mg/mL for B. mic. EA; MIC90 ranged from 0.156 mg/mL to 0.625 mg/mL and 0.0048 to 2.5 mg/mL for P. afr. EA and B. mic. EA respectively. There was a significant statistical difference observed in potency of both P. afr. EA and B. mic. A compared to the two antibiotics (P < 0.05). One hundred percent killing by P. afr EA was observed at 0.05 mg/mL (½ x MIC) and 0.2 mg/mL (2 x MIC) in 66 h for strain PE466C and PE252C respectively. For B. mic. EA, 100 percent killing effect of both strains (PE430C and PE369C) was observed at 0.1 mg/mL (2 x MIC) in 66 h. Qualitative phytochemical analysis confirmed the presence of alkaloids, flavonoids, steroids, tannins and saponins in the ethyl acetate extracts of both plants, which could be a potential template of lead molecule for the design of new anti- Helicobacter pylori therapies.
- Full Text:
Phytochemical analysis and bioactivity of selected South African medicinal plants on clinical isolates of Helicobacter pylori
- Authors: Njume, Collise
- Date: 2011
- Subjects: Helicobacter pylori , Medicinal plants -- Biotechnology , Traditional medicine -- South Africa -- Eastern Cape , Antibiotics , Drug resistance in microorganisms , Extracts , Helicobacter pylori infections
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11260 , http://hdl.handle.net/10353/449 , Helicobacter pylori , Medicinal plants -- Biotechnology , Traditional medicine -- South Africa -- Eastern Cape , Antibiotics , Drug resistance in microorganisms , Extracts , Helicobacter pylori infections
- Description: Medicinal plants have been used as traditional medicine in the treatment of numerous human diseases for thousands of years in many parts of the world. In the developing world, especially in rural areas, herbal remedies continue to be a primary source of medicine. Scientifically, medicinal plants have proven to be an abundant source of biologically active compounds, many of which have already been formulated into useful therapeutic substances or have provided a basis for the development of new lead molecules for pharmaceuticals. Antibiotic resistance, undesireable side effects and expences associated with the use of combination therapy in the treatment of Helicobacter pylori infections have generated a considerable interest in the study of medicinal plants as potential sources of new drugs against this organism. The high complexicity of bioactive compounds accumulated in plants coupled with their broad antimicrobial activity may make it difficult for pathogenic organisms, including H. pylori to acquire resistance during treatment. This study therefore evaluates the antimicrobial potential of selected South African medicinal plants employed in the treatment of H. pylori-related infections, and the subsequent isolation of the plant active principles. An ethnobotanical survey of plants used in the treatment of H. pylori-related infections was conducted in the study area. Crude extracts of Combretum molle, Sclerocarya birrea, Garcinia kola, Alepidea amatymbica and 2 Strychnos species were screened against 30 clinical strains of H. pylori and 2 standard control strains (NCTC 11638 and ATCC 43526). In the preliminary stages of this study, ethyl acetate, acetone, ethanol, methanol and water extracts of the plants were tested against H. pylori by agar well diffusion and micro broth dilution methods. The plant crude extracts that exhibited anti-H. pylori activity with a iv percentage susceptibility of 50 percent and above were considered for the rate of kill assays and the most active crude extracts selected for bio-assay guided isolation of the active ingredient. Preliminary fractionation of the crude extract was achieved by thin layer chromatography (TLC) using different solvent combinations; hexane/diethylether (HDE), ethyl acetate/methanol/water (EMW) and chloroform/ethyl acetate/formic acid (CEF) in order to determine the most suitable combination for column chromatography (CC) and subsequent testing by indirect bioautography. The extract was then fractionated in a silica gel column using previously determined solvent combinations as eluent. Active fractions obtained from column chromatography separations were further fractionated and the compounds identified by gas chromatography/mass spectrometry (GC/MS) analysis. All the plants exhibited antimicrobial activity against H. pylori with zone of inhibition diameters ranging from 0 - 38 mm and minimum inhibitory concentration (MIC) values ranging from 0.06 - 5.0 mg/mL. The most active plant extracts were the acetone extract of C. molle with a percentage susceptibility of 87.1 percent, acetone and aqueous extracts of S. birrea (71 percent each) and the ethanolic extracts of G. kola (53.3 percent). Except for the aqueous extract, these extracts also exhibited a strong bactericidal activity against H. pylori at different concentrations. TLC analysis revealed the presence of 9 components in the acetone extract of S. birrea with the EMW solvent system as opposed to 5 and 8 with HDE and CEF respectively. Bioassay-guided isolation led to the identification of 52 compounds from the acetone extract of S. birrea with n-octacosane being the most abundant (41.68 percent). This was followed by pyrrolidine (38.91 percent), terpinen-4-ol (38.3 percent), n-eicosane (24.98 percent), cyclopentane (16.76 percent), n-triacontane (16.28 percent), aromadendrene (13.63 percent) and α-gujunene (8.77 percent). Terpinen-4-ol and pyrrolidine demonstrated strong antimicrobial activity against H. pylori at all concentrations tested. These results may serve as preliminary scientific validation of the ethnomedicinal uses of the above mentioned plants in the treatment of H. pylori-related infections in South Africa. Terpinen-4-ol and pyrrolidine could be considered for further evaluation as therapeutic or prophylactic agents in the treatment of H. pylori-related infections. However, further investigations would be necessary to determine their toxicological properties, in-vivo potencies and mechanism of action against H.pylori
- Full Text:
- Authors: Njume, Collise
- Date: 2011
- Subjects: Helicobacter pylori , Medicinal plants -- Biotechnology , Traditional medicine -- South Africa -- Eastern Cape , Antibiotics , Drug resistance in microorganisms , Extracts , Helicobacter pylori infections
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11260 , http://hdl.handle.net/10353/449 , Helicobacter pylori , Medicinal plants -- Biotechnology , Traditional medicine -- South Africa -- Eastern Cape , Antibiotics , Drug resistance in microorganisms , Extracts , Helicobacter pylori infections
- Description: Medicinal plants have been used as traditional medicine in the treatment of numerous human diseases for thousands of years in many parts of the world. In the developing world, especially in rural areas, herbal remedies continue to be a primary source of medicine. Scientifically, medicinal plants have proven to be an abundant source of biologically active compounds, many of which have already been formulated into useful therapeutic substances or have provided a basis for the development of new lead molecules for pharmaceuticals. Antibiotic resistance, undesireable side effects and expences associated with the use of combination therapy in the treatment of Helicobacter pylori infections have generated a considerable interest in the study of medicinal plants as potential sources of new drugs against this organism. The high complexicity of bioactive compounds accumulated in plants coupled with their broad antimicrobial activity may make it difficult for pathogenic organisms, including H. pylori to acquire resistance during treatment. This study therefore evaluates the antimicrobial potential of selected South African medicinal plants employed in the treatment of H. pylori-related infections, and the subsequent isolation of the plant active principles. An ethnobotanical survey of plants used in the treatment of H. pylori-related infections was conducted in the study area. Crude extracts of Combretum molle, Sclerocarya birrea, Garcinia kola, Alepidea amatymbica and 2 Strychnos species were screened against 30 clinical strains of H. pylori and 2 standard control strains (NCTC 11638 and ATCC 43526). In the preliminary stages of this study, ethyl acetate, acetone, ethanol, methanol and water extracts of the plants were tested against H. pylori by agar well diffusion and micro broth dilution methods. The plant crude extracts that exhibited anti-H. pylori activity with a iv percentage susceptibility of 50 percent and above were considered for the rate of kill assays and the most active crude extracts selected for bio-assay guided isolation of the active ingredient. Preliminary fractionation of the crude extract was achieved by thin layer chromatography (TLC) using different solvent combinations; hexane/diethylether (HDE), ethyl acetate/methanol/water (EMW) and chloroform/ethyl acetate/formic acid (CEF) in order to determine the most suitable combination for column chromatography (CC) and subsequent testing by indirect bioautography. The extract was then fractionated in a silica gel column using previously determined solvent combinations as eluent. Active fractions obtained from column chromatography separations were further fractionated and the compounds identified by gas chromatography/mass spectrometry (GC/MS) analysis. All the plants exhibited antimicrobial activity against H. pylori with zone of inhibition diameters ranging from 0 - 38 mm and minimum inhibitory concentration (MIC) values ranging from 0.06 - 5.0 mg/mL. The most active plant extracts were the acetone extract of C. molle with a percentage susceptibility of 87.1 percent, acetone and aqueous extracts of S. birrea (71 percent each) and the ethanolic extracts of G. kola (53.3 percent). Except for the aqueous extract, these extracts also exhibited a strong bactericidal activity against H. pylori at different concentrations. TLC analysis revealed the presence of 9 components in the acetone extract of S. birrea with the EMW solvent system as opposed to 5 and 8 with HDE and CEF respectively. Bioassay-guided isolation led to the identification of 52 compounds from the acetone extract of S. birrea with n-octacosane being the most abundant (41.68 percent). This was followed by pyrrolidine (38.91 percent), terpinen-4-ol (38.3 percent), n-eicosane (24.98 percent), cyclopentane (16.76 percent), n-triacontane (16.28 percent), aromadendrene (13.63 percent) and α-gujunene (8.77 percent). Terpinen-4-ol and pyrrolidine demonstrated strong antimicrobial activity against H. pylori at all concentrations tested. These results may serve as preliminary scientific validation of the ethnomedicinal uses of the above mentioned plants in the treatment of H. pylori-related infections in South Africa. Terpinen-4-ol and pyrrolidine could be considered for further evaluation as therapeutic or prophylactic agents in the treatment of H. pylori-related infections. However, further investigations would be necessary to determine their toxicological properties, in-vivo potencies and mechanism of action against H.pylori
- Full Text:
Phytochemical analysis and bioactivity of the stem bark of Combretum Molle on some selected bacterial pathogens
- Authors: Nyenje, Mirriam, E
- Date: 2011
- Subjects: Drug resistance in microorganisms , Materia medica, Vegetable , Antibiotics , Microbial sensitivity tests , Gram-negative bacterial infections
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11261 , http://hdl.handle.net/10353/391 , Drug resistance in microorganisms , Materia medica, Vegetable , Antibiotics , Microbial sensitivity tests , Gram-negative bacterial infections
- Description: Antimicrobial resistance is a worldwide problem that has deleterious long-term effects as the development of drug resistance outpaces the development of new drugs. Plants have been used for many generations for healing purposes, and screening of extracts of these plants has often yielded positive outcomes. This study was aimed at isolating and characterizing the major active antimicrobial compounds present in the stem bark of C. molle, in a bid to identify potential sources of cheap starting materials for the synthesis of new drugs. Various solvents (hexane, ethyl acetate, dichloromethane, acetone, ethanol and methanol) were used for extraction. The agar well diffusion technique was used to screen for antimicrobial activity of C. molle extracts against Streptococcus pyogenes ATCC 49399, Plesiomonas shigelloides ATCC 51903, Pseudomonas aeruginosa ATCC 15442, Helicobacter pylori ATCC 43526 and Helicobacter pylori 252C (clinical isolate); minimum inhibition concentration (MIC) of the most active extracts was determined by the broth dilution method. Fractionation of acetone extract was done by thin layer chromatography (TLC) and bioautography to determine the compounds present and their antimicrobial activity respectively. The acetone extract was purified by column chromatography and their MIC determined. The most potent fraction (EA4) was subjected to Gas chromatography- Mass spectrometry (GC-MS) and High performance liquid chromatography (HPLC) for identification of the active compounds. Results were analyzed by the Fisher‟s exact test. All the extracts tested demonstrated antimicrobial activity with zone diameters of inhibition ranging from 0–32 mm. Acetone was the most potent extract with its MIC ranging from 0.078–5.0 mg/mL. Seventeen fractions were collected from column chromatography and the most active fraction against all the organisms was EA 4 (eluted with 100 percent ethyl acetate), with its MIC ranging from 0.078 - 2.5mg/mL. There was no statistically significant difference (P>0.05) in the potency of the xii four extracts (acetone, methanol, ethanol and ethyl acetate) and antibiotic (ciprofloxacin) on the different bacterial strains tested, likewise the crude extract and the fractions. No compound was detected by GC-MS whereas numerous peaks were identified by HPLC implying that the active compounds in this plant are non volatile. We could not identify the compounds thereby proposing further studies using Nuclear magnetic resonance to identify the compounds. The study revealed that the acetone extract of C. molle was the most active against all the test organisms and therefore justifies the use of this plant in traditional medicine.
- Full Text:
- Authors: Nyenje, Mirriam, E
- Date: 2011
- Subjects: Drug resistance in microorganisms , Materia medica, Vegetable , Antibiotics , Microbial sensitivity tests , Gram-negative bacterial infections
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11261 , http://hdl.handle.net/10353/391 , Drug resistance in microorganisms , Materia medica, Vegetable , Antibiotics , Microbial sensitivity tests , Gram-negative bacterial infections
- Description: Antimicrobial resistance is a worldwide problem that has deleterious long-term effects as the development of drug resistance outpaces the development of new drugs. Plants have been used for many generations for healing purposes, and screening of extracts of these plants has often yielded positive outcomes. This study was aimed at isolating and characterizing the major active antimicrobial compounds present in the stem bark of C. molle, in a bid to identify potential sources of cheap starting materials for the synthesis of new drugs. Various solvents (hexane, ethyl acetate, dichloromethane, acetone, ethanol and methanol) were used for extraction. The agar well diffusion technique was used to screen for antimicrobial activity of C. molle extracts against Streptococcus pyogenes ATCC 49399, Plesiomonas shigelloides ATCC 51903, Pseudomonas aeruginosa ATCC 15442, Helicobacter pylori ATCC 43526 and Helicobacter pylori 252C (clinical isolate); minimum inhibition concentration (MIC) of the most active extracts was determined by the broth dilution method. Fractionation of acetone extract was done by thin layer chromatography (TLC) and bioautography to determine the compounds present and their antimicrobial activity respectively. The acetone extract was purified by column chromatography and their MIC determined. The most potent fraction (EA4) was subjected to Gas chromatography- Mass spectrometry (GC-MS) and High performance liquid chromatography (HPLC) for identification of the active compounds. Results were analyzed by the Fisher‟s exact test. All the extracts tested demonstrated antimicrobial activity with zone diameters of inhibition ranging from 0–32 mm. Acetone was the most potent extract with its MIC ranging from 0.078–5.0 mg/mL. Seventeen fractions were collected from column chromatography and the most active fraction against all the organisms was EA 4 (eluted with 100 percent ethyl acetate), with its MIC ranging from 0.078 - 2.5mg/mL. There was no statistically significant difference (P>0.05) in the potency of the xii four extracts (acetone, methanol, ethanol and ethyl acetate) and antibiotic (ciprofloxacin) on the different bacterial strains tested, likewise the crude extract and the fractions. No compound was detected by GC-MS whereas numerous peaks were identified by HPLC implying that the active compounds in this plant are non volatile. We could not identify the compounds thereby proposing further studies using Nuclear magnetic resonance to identify the compounds. The study revealed that the acetone extract of C. molle was the most active against all the test organisms and therefore justifies the use of this plant in traditional medicine.
- Full Text:
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