Challenges on learning and teaching of fraction operations in Grade 6 - a case study in a South African primary school
- Authors: Chetty, Ashnee
- Date: 2019
- Subjects: Mathematics -- Study and teaching (Primary) Mathematics -- Study and teaching (Early childhood)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/15869 , vital:40534
- Description: Literature review indicates that world over, fraction operations in primary school are challenging not only for learners but also for teachers and South Africa is not an exception. There have been studies on challenges of fraction operations, but could not locate any study at a Grade 6 level in East London education district. The purpose of this study was to assess the specific strengths and challenges in the learning and teaching of fraction operations in Grade 6 in one of the schools in this district. The research paradigm for this study was post-positivism which adopted a mixed methods approach, utilising both quantitative and qualitative methods. The population consisted of three teachers and 98 Grade 6 learners in one primary school in East London. The learners were under 18 years and in order to comply with South African ethical regulations involving humans, a letter was sent out to all 98 Grade 6 learners’ parents requesting their consent. Only 59 learners brought back the consent letters signed by a parent or legal guardian and hence, the sample consisted of 59 Grade 6 learners. There were two instruments: a survey questionnaire with 15 items for learners and two interview schedules, one for teachers and another for learners. The time to complete the questionnaire was 45 minutes and the time to complete the interviews was less than 20 minutes for learners and 40 minutes for teachers. As part of a pilot study, the questionnaire was given to six learners in 2017 cohort. Also, the questionnaire was given two colleagues teaching Grade 6 from two different schools. Furthermore, two learners from the 2017 cohort and two colleagues from two different schools were interviewed, respectively, to check the validity of the learners’ and teachers’ interview schedules. Based on the feedback, the instruments were modified for use in 2018. The learners were given the questionnaire to answer first before 10 were selected for interviews. Three teachers, one each from Grades 5, 6 and 7 were interviewed. The quantitative data were analysed to lead to a descriptive data presentation. The qualitative data were analysed thematically. It was revealed that there were similarities and differences in the manner in which teachers teach and the challenges they identified. There were similarities and differences among the responses from the learners. They found certain fraction operations challenging and their strengths were similar as well. The common outline of the learners’ strengths were being able to do like-fractions while, their challenges were on doing unlike-fractions. The teachers too concurred with the learners’ views. The learners got confused because they did not understand fractions as part of a whole. The teachers indicated knowledge of more than one teaching method. The teachers also pointed out how times tables is an essential part of being able to do operations of fractions. This study could be beneficial for teachers, learners, parents and curriculum developers. The curriculum developers need to revisit the time frame, the transition between the grades, and how often the concept of fractions appears throughout every term.
- Full Text:
- Authors: Chetty, Ashnee
- Date: 2019
- Subjects: Mathematics -- Study and teaching (Primary) Mathematics -- Study and teaching (Early childhood)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/15869 , vital:40534
- Description: Literature review indicates that world over, fraction operations in primary school are challenging not only for learners but also for teachers and South Africa is not an exception. There have been studies on challenges of fraction operations, but could not locate any study at a Grade 6 level in East London education district. The purpose of this study was to assess the specific strengths and challenges in the learning and teaching of fraction operations in Grade 6 in one of the schools in this district. The research paradigm for this study was post-positivism which adopted a mixed methods approach, utilising both quantitative and qualitative methods. The population consisted of three teachers and 98 Grade 6 learners in one primary school in East London. The learners were under 18 years and in order to comply with South African ethical regulations involving humans, a letter was sent out to all 98 Grade 6 learners’ parents requesting their consent. Only 59 learners brought back the consent letters signed by a parent or legal guardian and hence, the sample consisted of 59 Grade 6 learners. There were two instruments: a survey questionnaire with 15 items for learners and two interview schedules, one for teachers and another for learners. The time to complete the questionnaire was 45 minutes and the time to complete the interviews was less than 20 minutes for learners and 40 minutes for teachers. As part of a pilot study, the questionnaire was given to six learners in 2017 cohort. Also, the questionnaire was given two colleagues teaching Grade 6 from two different schools. Furthermore, two learners from the 2017 cohort and two colleagues from two different schools were interviewed, respectively, to check the validity of the learners’ and teachers’ interview schedules. Based on the feedback, the instruments were modified for use in 2018. The learners were given the questionnaire to answer first before 10 were selected for interviews. Three teachers, one each from Grades 5, 6 and 7 were interviewed. The quantitative data were analysed to lead to a descriptive data presentation. The qualitative data were analysed thematically. It was revealed that there were similarities and differences in the manner in which teachers teach and the challenges they identified. There were similarities and differences among the responses from the learners. They found certain fraction operations challenging and their strengths were similar as well. The common outline of the learners’ strengths were being able to do like-fractions while, their challenges were on doing unlike-fractions. The teachers too concurred with the learners’ views. The learners got confused because they did not understand fractions as part of a whole. The teachers indicated knowledge of more than one teaching method. The teachers also pointed out how times tables is an essential part of being able to do operations of fractions. This study could be beneficial for teachers, learners, parents and curriculum developers. The curriculum developers need to revisit the time frame, the transition between the grades, and how often the concept of fractions appears throughout every term.
- Full Text:
Examining the cognitive learning effect on grade 10 students’ performance in physical science in selected schools in Umgungudlovu Education District
- Authors: Olorunda, David Oluyemi
- Date: 2019
- Subjects: Cognitive learning Learning, Psychology of
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/16577 , vital:40733
- Description: The study employed a quantitative as well as a qualitative approach. Four public schools in the uMgungundlovu District participated in this study. The identities of all respondents were protected. The sample included 154 participants, four Physical science educators and four Heads of department selected purposefully across four secondary schools. The study found that themajority of the learners reported that they have interest and positive attitude for Physical science but most of learners indicated they understanding when English is used as a medium of instruction in teaching Physical science but someprefer other languages to be used for their understanding. It was obvious that most parents lacked knowledge about Physical Sciences and could not assist their children. It was also indicated that their teachers are approachable especially for personal explanation giving them attention whenever they ask for assistance, creating an atmosphere that makes it easy for the learner to learn. The study reveals that learners had a high rate of their teachers motivating them enough to like physical science, by using different method for them to understand the subject and majority follow their teacher’s method but only few learners use their own method.The educators and the heads of departments confirmed that they do give the learners different method. Many learners understands what they are taught using diagrams and illustrations in order to make them understand in all subject study showed that the head of departments indicatedthat they do check the way the teachers teach for effectiveness on the part of the teachers in ,line with the curriculum assessment policy statement from the department of education .The educators said they receive their educational in- service training and done yearly at the department of education workshop and moderations. Findings from this research reveals that learners learns one way or the other through all the strategies of learning but most learners affirms that they learn more rehearsal where they have to repeat things more and that the physical sciences teacher should have more time and explain thoroughly particular term, using diagrams and illustrations in order to make them understand in all subject. The study concluded by giving general recommendations for improving learners’ participation and attitudes towards learning physical Science. Recommendations for improvement in the areas identified were III provided and topics for future research on the curriculum of Grade 10 Physical Sciences were suggested in order to improve on physical science.
- Full Text:
- Authors: Olorunda, David Oluyemi
- Date: 2019
- Subjects: Cognitive learning Learning, Psychology of
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/16577 , vital:40733
- Description: The study employed a quantitative as well as a qualitative approach. Four public schools in the uMgungundlovu District participated in this study. The identities of all respondents were protected. The sample included 154 participants, four Physical science educators and four Heads of department selected purposefully across four secondary schools. The study found that themajority of the learners reported that they have interest and positive attitude for Physical science but most of learners indicated they understanding when English is used as a medium of instruction in teaching Physical science but someprefer other languages to be used for their understanding. It was obvious that most parents lacked knowledge about Physical Sciences and could not assist their children. It was also indicated that their teachers are approachable especially for personal explanation giving them attention whenever they ask for assistance, creating an atmosphere that makes it easy for the learner to learn. The study reveals that learners had a high rate of their teachers motivating them enough to like physical science, by using different method for them to understand the subject and majority follow their teacher’s method but only few learners use their own method.The educators and the heads of departments confirmed that they do give the learners different method. Many learners understands what they are taught using diagrams and illustrations in order to make them understand in all subject study showed that the head of departments indicatedthat they do check the way the teachers teach for effectiveness on the part of the teachers in ,line with the curriculum assessment policy statement from the department of education .The educators said they receive their educational in- service training and done yearly at the department of education workshop and moderations. Findings from this research reveals that learners learns one way or the other through all the strategies of learning but most learners affirms that they learn more rehearsal where they have to repeat things more and that the physical sciences teacher should have more time and explain thoroughly particular term, using diagrams and illustrations in order to make them understand in all subject. The study concluded by giving general recommendations for improving learners’ participation and attitudes towards learning physical Science. Recommendations for improvement in the areas identified were III provided and topics for future research on the curriculum of Grade 10 Physical Sciences were suggested in order to improve on physical science.
- Full Text:
Social Media Conspicuous Consumptive Behaviour and Consumers’ Purchase Intentions of Luxury Goods
- Authors: Madzunya, Ntsundeni
- Date: 2018
- Subjects: Consumer behavior -- South Africa Social media -- Marketing
- Language: English
- Type: Thesis , Masters , MCom (Business Management)
- Identifier: http://hdl.handle.net/10353/13524 , vital:39676
- Description: Social media has grown to such a large extent that it has become a primary source of information among consumers online. The impact of the growth of popular social media sites such as Facebook and Instagram have allowed for interest in consumer online behaviour to increase. There is no specific social media model that can be used as a tool to understand its use and influence on conspicuous online consumption behaviour. The study aimed to develop and apply a model used to understand consumer behaviour in order to enhance the use of the communication landscape as a means to drive purchase intentions. Therefore, the purpose of this study was to investigate the effects of social media conspicuous consumptive behaviour on intention to purchase luxury goods. The primary objective of this study was to examine the effect of conspicuous consumptive behaviour facilitated by Instagram and Facebook on potential buyers’ intention to purchase luxury goods. The study also determined if Instagram and Facebook usage intensity has an influence on conspicuous consumptive behaviour. In addition, the study also examined the relationship between Instagram and Facebook eWOM credibility and conspicuous consumptive behaviour. The study was underpinned by a positivist paradigm, a quantitative approach and the appropriate descriptive research design. Data was collected from both primary and secondary sources. An online survey was conducted to collect primary data, through the use of a questionnaire developed from previous studies. The questionnaire was administered online through the Survey Monkey platform to a total of 364 respondents. Analysis and interpretation of findings was done using both the descriptive and inferential statistical measures, with the help of Statistical Package for Social Scientists (SPSS) 24 and Lisrel (version 9). The scales adopted for the study consisted of eight constructs, Instagram usage intensity, Instagram eWOM credibility, Instagram conspicuous consumptive behaviour, Instagram intention to purchase luxury goods, Facebook usage intensity, Facebook eWOM credibility, Facebook conspicuous consumptive behaviour, Facebook intention to purchase luxury goods. All the scales used in this study were found to be reliable and valid. ii Based on the 364 responses, the study found a positive relationship between both Facebook and Instagram usage intensity and conspicuous consumptive behaviour. Conversely, results showed that eWOM credibility on both Facebook and Instagram had no relationship with conspicuous consumptive behaviour. Lastly, Instagram conspicuous consumptive behaviour had a positive relationship with the intention to purchase luxury goods. A similar finding was found for Facebook conspicuous consumptive behaviour and the intention to purchase luxury goods. Luxury marketers are encouraged to formulate social media strategies that emphasise consumer involvement, engagement and trust; this, in turn, will increase total social media usage and influence. However, further research may want to include other popular social media platforms, such as Twitter and WhatsApp, to gain a wider understanding of the effect of social media conspicuous consumptive behaviour on intention to purchase luxury goods.
- Full Text:
- Authors: Madzunya, Ntsundeni
- Date: 2018
- Subjects: Consumer behavior -- South Africa Social media -- Marketing
- Language: English
- Type: Thesis , Masters , MCom (Business Management)
- Identifier: http://hdl.handle.net/10353/13524 , vital:39676
- Description: Social media has grown to such a large extent that it has become a primary source of information among consumers online. The impact of the growth of popular social media sites such as Facebook and Instagram have allowed for interest in consumer online behaviour to increase. There is no specific social media model that can be used as a tool to understand its use and influence on conspicuous online consumption behaviour. The study aimed to develop and apply a model used to understand consumer behaviour in order to enhance the use of the communication landscape as a means to drive purchase intentions. Therefore, the purpose of this study was to investigate the effects of social media conspicuous consumptive behaviour on intention to purchase luxury goods. The primary objective of this study was to examine the effect of conspicuous consumptive behaviour facilitated by Instagram and Facebook on potential buyers’ intention to purchase luxury goods. The study also determined if Instagram and Facebook usage intensity has an influence on conspicuous consumptive behaviour. In addition, the study also examined the relationship between Instagram and Facebook eWOM credibility and conspicuous consumptive behaviour. The study was underpinned by a positivist paradigm, a quantitative approach and the appropriate descriptive research design. Data was collected from both primary and secondary sources. An online survey was conducted to collect primary data, through the use of a questionnaire developed from previous studies. The questionnaire was administered online through the Survey Monkey platform to a total of 364 respondents. Analysis and interpretation of findings was done using both the descriptive and inferential statistical measures, with the help of Statistical Package for Social Scientists (SPSS) 24 and Lisrel (version 9). The scales adopted for the study consisted of eight constructs, Instagram usage intensity, Instagram eWOM credibility, Instagram conspicuous consumptive behaviour, Instagram intention to purchase luxury goods, Facebook usage intensity, Facebook eWOM credibility, Facebook conspicuous consumptive behaviour, Facebook intention to purchase luxury goods. All the scales used in this study were found to be reliable and valid. ii Based on the 364 responses, the study found a positive relationship between both Facebook and Instagram usage intensity and conspicuous consumptive behaviour. Conversely, results showed that eWOM credibility on both Facebook and Instagram had no relationship with conspicuous consumptive behaviour. Lastly, Instagram conspicuous consumptive behaviour had a positive relationship with the intention to purchase luxury goods. A similar finding was found for Facebook conspicuous consumptive behaviour and the intention to purchase luxury goods. Luxury marketers are encouraged to formulate social media strategies that emphasise consumer involvement, engagement and trust; this, in turn, will increase total social media usage and influence. However, further research may want to include other popular social media platforms, such as Twitter and WhatsApp, to gain a wider understanding of the effect of social media conspicuous consumptive behaviour on intention to purchase luxury goods.
- Full Text:
Implementation of the policy on religious equity in public schools in the East London Education District : towards a framework for religious diversity
- Makasi, Cordelia Noma-Abysinia
- Authors: Makasi, Cordelia Noma-Abysinia
- Date: 2017
- Subjects: Religious education -- South Africa -- Eastern Cape Religion and state -- South Africa -- Eastern Cape Christianity and politics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5014 , vital:28935
- Description: The study sought to establish the implementation of the policy on religious equity in public schools in the East London Education district in the Eastern Cape Province of South Africa. Underpinned by Van Meter and Van Horn (2015) with implementation and conceptual theory and also a theory on opportunity to learn and school performance by Van Der Grift and Houtveen(2006), the study was located in the pragmatist research paradigm and followed a mixed methods approach and concurrent triangulation design. The research sampling technique was random for high school learners in selected schools and purposeful for principals, heads of departments, teachers and provincial education officials. Three methods were employed to collect data from selected public schools and from the provincial office namely; semi-structured interviews, individual interviews and observation. Quantitative data were analysed statistically and presented in the form of descriptive statistics. Qualitative data were analysed using the thematic content analysis technique. Major findings of the study are that teachers and principals understood the concept religious equity and had a fair understanding of the policy on religious equity. Schools were predominantly Christian-oriented in terms of religious practices and there were no recorded cases of religious conflict. Learners of minority religions were not compelled to attend Christian religious functions in schools and were allowed to attend their own religious functions outside school. This was established from the fact that participants cited freedom of religion as being exercised in schools. However, it was further established that there was no strategic monitoring and support for teachers in the implementation of religious equity. There were also no deliberate measures and strategies for the implementation of religious equity suggesting challenges and inconsistencies in the implementation of the policy. While there were notable challenges in the implementation of the policy, due to resistance of stakeholders to change, schools had great opportunities which could be utilized to enhance the implementation of the policy on religious equity. The study concludes by noting that, while key policy implementers had an understanding of religious equity, the situation on the ground revealed challenges and inconsistencies in the implementation of the policy which resulted in a Christian-dominated school environment at the expense of minority religions The study recommends, among other things, that that religious equity be adhered to as enshrined in the Constitution of South Africa of 1996 and the South African Schools Act of 1996. The teaching and learning environment should include Religion Education as per prescription by National Policy on Religion Education of 2003, that monitoring and support of teachers be done, and that community involvement with policy development be considered crucial as well as moral education teaching in schools. A framework for enhancing implementation of the policy on religious equity is also proposed.
- Full Text:
- Authors: Makasi, Cordelia Noma-Abysinia
- Date: 2017
- Subjects: Religious education -- South Africa -- Eastern Cape Religion and state -- South Africa -- Eastern Cape Christianity and politics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5014 , vital:28935
- Description: The study sought to establish the implementation of the policy on religious equity in public schools in the East London Education district in the Eastern Cape Province of South Africa. Underpinned by Van Meter and Van Horn (2015) with implementation and conceptual theory and also a theory on opportunity to learn and school performance by Van Der Grift and Houtveen(2006), the study was located in the pragmatist research paradigm and followed a mixed methods approach and concurrent triangulation design. The research sampling technique was random for high school learners in selected schools and purposeful for principals, heads of departments, teachers and provincial education officials. Three methods were employed to collect data from selected public schools and from the provincial office namely; semi-structured interviews, individual interviews and observation. Quantitative data were analysed statistically and presented in the form of descriptive statistics. Qualitative data were analysed using the thematic content analysis technique. Major findings of the study are that teachers and principals understood the concept religious equity and had a fair understanding of the policy on religious equity. Schools were predominantly Christian-oriented in terms of religious practices and there were no recorded cases of religious conflict. Learners of minority religions were not compelled to attend Christian religious functions in schools and were allowed to attend their own religious functions outside school. This was established from the fact that participants cited freedom of religion as being exercised in schools. However, it was further established that there was no strategic monitoring and support for teachers in the implementation of religious equity. There were also no deliberate measures and strategies for the implementation of religious equity suggesting challenges and inconsistencies in the implementation of the policy. While there were notable challenges in the implementation of the policy, due to resistance of stakeholders to change, schools had great opportunities which could be utilized to enhance the implementation of the policy on religious equity. The study concludes by noting that, while key policy implementers had an understanding of religious equity, the situation on the ground revealed challenges and inconsistencies in the implementation of the policy which resulted in a Christian-dominated school environment at the expense of minority religions The study recommends, among other things, that that religious equity be adhered to as enshrined in the Constitution of South Africa of 1996 and the South African Schools Act of 1996. The teaching and learning environment should include Religion Education as per prescription by National Policy on Religion Education of 2003, that monitoring and support of teachers be done, and that community involvement with policy development be considered crucial as well as moral education teaching in schools. A framework for enhancing implementation of the policy on religious equity is also proposed.
- Full Text:
Pharmacological investigations of Kedrostis africana (L.) Cogn. and Vernonia mespilifolia Less. used in folk medicine in the Eastern Cape, South Africa
- Authors: Unuofin, Jeremiah Oshiomame
- Date: 2017
- Subjects: Medicinal plants -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9231 , vital:34307
- Description: The prevalence of obesity and its co-morbidity is increasing in South Africa. High calorie diet, sedentary lifestyle and the cultural belief that being fat or obese signifies beauty, wellness and wealth are major causative factors. This study was undertaken to scientifically validate two major medicinal plants used traditionally in the Raymond Mhlaba Municipality for the mespilifolia Less. were used singly and in combination. According to ethnobotanical studies,these two plants are regarded as wild plants and are only used for medicinal purposes. There has been a dearth of scientific reports on the two plants and to the best of our knowledge, this study is the first to investigate the nutritional, antioxidant, antimicrobial, safety and anti-obesity potentials of the two plants and their combination. This study revealed that both plants are rich in nutrients. K. africana had greater ash (16.28 percent), crude fat (1.12 percent), Ca (2505 mg/100g), Mg (485 mg/100g) and Fe (89.95 mg/100g) while V. mespilifolia showed higher crude fibre (29.24 percent), crude protein (10.75 percent), P (400 mg/100g), Na (570 mg/100g), Cu (1.55 mg/100g) and Mn (4.70 mg/100g). K. africana and V. mespilifolia both contributed 223.37 Kcal/kg and 237.37 Kcal/kg of energy respectively. The polyphenolic evaluation of the acetone, aqueous and ethanol extracts of the plants revealed that the acetone extract of the combination of both plants had higher total phenol (144.59 mgGAE/g) and flavonoid (803.93 mgQE/g) contents, the ethanol extract of the combined plant also had the highest tannin contents (1.25 mgTAE/g), while the acetone extracts of K. Africana had the highest proanthocyanidin content (585 mgCE/g). The antioxidant assays revealed that the ethanol extract for V. mespilifolia had higher scavenging potentials of ABTS, DPPH and vinitric oxide radicals while the aqueous extract of the combination of both had higher scavenging potential for hydrogen peroxide radicals. Evaluation of antimicrobial potential of the extracts using the minimial inhibitory concentration (MIC) assay against 6 bacteria (Actinomyces odontolyticus, Lactobacillus sakei, Staphylococcus aureus, Enterobacter cloacae, Pseudomonas aeruginosa and Bacteriodes thetaiotomicron) and 4 fungi (Candida albicans, Microsporium gypsum, Penicillium chrysogenum and Trichophyton tonsurans) revealed that the plants possess antimicrobial activity. The MIC of the extracts against the tested bacterial strains ranged from 2.5 mg/mL to 5 mg/mL acetone and ethanol extracts of V. mespilifolia and the combined plants as well as the ethanol extracts of K. africana. However, no activity was observed for the acetone extract of K. africana and aqueous extracts of V. mespilifolia and the combination of both plants. Only three fungal strains (Candida albicans, Microsporium gypsum and Penicillium chrysogenum) were susceptible to the organic extracts with an MIC 0.3125 mg/mL to 5 mg/mL while the aqueous extracts showed no activity against all the fungal strains. None of the plant extracts showed any activity against Trichophyton tonsurans. The brine shrimp toxicity test revealed that all the three extracts of V. mespilifolia, aqueous and ethanol extracts of K. africana and aqueous and acetone extracts of the combination of both plants were toxic in relative to Meyer’s index and other indices of toxicity. The cytotoxic effect of the aqueous and ethanol extracts of V. mespilifolia, K. africana and their combination were also evaluated using HeLa cells. From this study, all the extracts tested had IC50 values were greater than 20 μg/mL which connotes that they are not toxic. According to the American National Cancer Institute, crude plant extracts are considered cytotoxic in an in vitro assay when concentrations 20 μg/mL and below produce 50% inhibition of tumor cells, after an exposure time of 48 hours. In vivo acute evaluation of single oral administration of 2000 and 5000/kg body weight did not produce mortality or significant behavioral changes during 14 days observation. In addition, the sub-acute administration of the aqueous extract at 200, 400 and 600 mg/kg/bwt/ day over a period of 28 days revealed no mortality or morbidity. The weekly body and organ weight of the rats were not significantly different from those of the controls and extract treated rats. The aqueous extracts at all doses did not show any significant (p > 0.05) effect on biomarkers of liver and renal damage. Haematological evaluation revealed that oral administration of aqueous extracts of K. africana, V. mespilifolia and the combination of both plants did not induce anaemia or leucocytosis in the animals. Furthermore, histopathological evaluation of the internal organs revealed no detectable inflammation at the the doses administered over a period of 28 days. These results demonstrated that the aqueous extracts of K. africana, V. mespilifolia and the combination of both plants was potentially safe for consumption orally even in chronic administration. Enzyme based in-vitro antiobesity evaluation of the aqueous and ethanolic extracts of K. africana, V. mespilifolia and their combination revealed that the ethanol extracts of both plants and their combination exhibited moderate inhibitory activities against α-amylase, α- glucosidase and pancreatic lipase. However, the standards used for the various inhibition assays exhibited much higher inhibitory actions when compared to any of the extracts. This suggests that the mechanism by which these two plants and their combination exert anti-obesity effects are probably not by inhibition of key enzymes of carbohydrate and fat metabolism.
- Full Text:
- Authors: Unuofin, Jeremiah Oshiomame
- Date: 2017
- Subjects: Medicinal plants -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9231 , vital:34307
- Description: The prevalence of obesity and its co-morbidity is increasing in South Africa. High calorie diet, sedentary lifestyle and the cultural belief that being fat or obese signifies beauty, wellness and wealth are major causative factors. This study was undertaken to scientifically validate two major medicinal plants used traditionally in the Raymond Mhlaba Municipality for the mespilifolia Less. were used singly and in combination. According to ethnobotanical studies,these two plants are regarded as wild plants and are only used for medicinal purposes. There has been a dearth of scientific reports on the two plants and to the best of our knowledge, this study is the first to investigate the nutritional, antioxidant, antimicrobial, safety and anti-obesity potentials of the two plants and their combination. This study revealed that both plants are rich in nutrients. K. africana had greater ash (16.28 percent), crude fat (1.12 percent), Ca (2505 mg/100g), Mg (485 mg/100g) and Fe (89.95 mg/100g) while V. mespilifolia showed higher crude fibre (29.24 percent), crude protein (10.75 percent), P (400 mg/100g), Na (570 mg/100g), Cu (1.55 mg/100g) and Mn (4.70 mg/100g). K. africana and V. mespilifolia both contributed 223.37 Kcal/kg and 237.37 Kcal/kg of energy respectively. The polyphenolic evaluation of the acetone, aqueous and ethanol extracts of the plants revealed that the acetone extract of the combination of both plants had higher total phenol (144.59 mgGAE/g) and flavonoid (803.93 mgQE/g) contents, the ethanol extract of the combined plant also had the highest tannin contents (1.25 mgTAE/g), while the acetone extracts of K. Africana had the highest proanthocyanidin content (585 mgCE/g). The antioxidant assays revealed that the ethanol extract for V. mespilifolia had higher scavenging potentials of ABTS, DPPH and vinitric oxide radicals while the aqueous extract of the combination of both had higher scavenging potential for hydrogen peroxide radicals. Evaluation of antimicrobial potential of the extracts using the minimial inhibitory concentration (MIC) assay against 6 bacteria (Actinomyces odontolyticus, Lactobacillus sakei, Staphylococcus aureus, Enterobacter cloacae, Pseudomonas aeruginosa and Bacteriodes thetaiotomicron) and 4 fungi (Candida albicans, Microsporium gypsum, Penicillium chrysogenum and Trichophyton tonsurans) revealed that the plants possess antimicrobial activity. The MIC of the extracts against the tested bacterial strains ranged from 2.5 mg/mL to 5 mg/mL acetone and ethanol extracts of V. mespilifolia and the combined plants as well as the ethanol extracts of K. africana. However, no activity was observed for the acetone extract of K. africana and aqueous extracts of V. mespilifolia and the combination of both plants. Only three fungal strains (Candida albicans, Microsporium gypsum and Penicillium chrysogenum) were susceptible to the organic extracts with an MIC 0.3125 mg/mL to 5 mg/mL while the aqueous extracts showed no activity against all the fungal strains. None of the plant extracts showed any activity against Trichophyton tonsurans. The brine shrimp toxicity test revealed that all the three extracts of V. mespilifolia, aqueous and ethanol extracts of K. africana and aqueous and acetone extracts of the combination of both plants were toxic in relative to Meyer’s index and other indices of toxicity. The cytotoxic effect of the aqueous and ethanol extracts of V. mespilifolia, K. africana and their combination were also evaluated using HeLa cells. From this study, all the extracts tested had IC50 values were greater than 20 μg/mL which connotes that they are not toxic. According to the American National Cancer Institute, crude plant extracts are considered cytotoxic in an in vitro assay when concentrations 20 μg/mL and below produce 50% inhibition of tumor cells, after an exposure time of 48 hours. In vivo acute evaluation of single oral administration of 2000 and 5000/kg body weight did not produce mortality or significant behavioral changes during 14 days observation. In addition, the sub-acute administration of the aqueous extract at 200, 400 and 600 mg/kg/bwt/ day over a period of 28 days revealed no mortality or morbidity. The weekly body and organ weight of the rats were not significantly different from those of the controls and extract treated rats. The aqueous extracts at all doses did not show any significant (p > 0.05) effect on biomarkers of liver and renal damage. Haematological evaluation revealed that oral administration of aqueous extracts of K. africana, V. mespilifolia and the combination of both plants did not induce anaemia or leucocytosis in the animals. Furthermore, histopathological evaluation of the internal organs revealed no detectable inflammation at the the doses administered over a period of 28 days. These results demonstrated that the aqueous extracts of K. africana, V. mespilifolia and the combination of both plants was potentially safe for consumption orally even in chronic administration. Enzyme based in-vitro antiobesity evaluation of the aqueous and ethanolic extracts of K. africana, V. mespilifolia and their combination revealed that the ethanol extracts of both plants and their combination exhibited moderate inhibitory activities against α-amylase, α- glucosidase and pancreatic lipase. However, the standards used for the various inhibition assays exhibited much higher inhibitory actions when compared to any of the extracts. This suggests that the mechanism by which these two plants and their combination exert anti-obesity effects are probably not by inhibition of key enzymes of carbohydrate and fat metabolism.
- Full Text:
- «
- ‹
- 1
- ›
- »