Biological activities of tulbaghia violacea against cryptococcus species
- Authors: Mitradev, Pattoo
- Date: 2018
- Subjects: Violaceae -- Therapeutic use -- South Africa , Anticoagulants (Medicine) , Medicinal plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/32772 , vital:32357
- Description: Cryptococcus neoformans and Cryptococcus gattii, which are environmental yeasts, are the etiological agents of cryptococcosis in both immunocompromised and immunocompetent individuals, and account for high mortality and morbidity rates in sub-Saharan Africa. The current antifungal agents used for treatment of cryptococcal infections either target the fungal cell wall (β-(1,3) glucan and chitin) or cell membrane directly or ergosterol biosynthetic pathways or fungal DNA and RNA. Gaps in antifungal therapy include the unavailability and exhorbitant costs of these drugs especially to patients in the developing world. Drug resistance to conventional drugs is also an ever-increasing problem. It is therefore essential to find alternative natural compounds from medicinal plants that are safer, cheaper and more widely available. Tulbaghia violacea, also known as wild garlic, has been used as a traditional remedy in South Africa for the treatment of several ailments. Aqueous and organic extracts of the plant have been demonstrated to have antimicrobial and antifungal activity against several pathogens. However, there is a huge gap in our current knowledge in that the mechanism/s of action/s of these extracts have not been fully investigated. The focus of the current study therefore was to determine whether T. violacea extracts from the roots, rhizome, leaves and tubers exhibited antifungal activity against C. neoformans and C. gattii and to evaluate the ability of the rhizome extract to induce changes in key fungal virulence factors. Three mechanisms (ergosterol, β-(1,3) glucan and chitin production) regulating the antifungal activity of the rhizome extract were also examined. In the current study, phytochemical analysis of aqueous extracts of the roots, leaves, rhizomes and tubers showed that the rhizomes had the highest phenolic, saponin and tannin content when compared to the other plant organs. Fingerprinting by GC-MS revealed identical compounds in the different plant parts with the detection of 4 H Pyran-4-one DDMP (known antifungal), previously unreported in studies on T. violacea. The bulk of the extract comprised of 40% sulphur-containing and 20% furan-containing compounds. The remaining minor compounds comprised of 2x alcohols (13.3%), 1x pyran (6.7%), 1x ketone (6.7%), 1x halogen (6.7%) and 1x acid (6.7%) compounds. The rhizomes also had highest content of 2 methyl methioacetic acid, benzophenone and chloromethyl methylsulfide compared to the other plant parts. The rhizomes were found to be more potent against both pathogenic fungi tested here with an MIC and MFC of 1.25 mg/ml. Nystatin was included as a positive control when determining the MIC’s and MFC’s of the different plant extracts. The antifungal nature of the T. violacea extracts in the current study may be due to the synergistic effects of the sulphide, furan, pyran and ketone compounds present in the extracts, but this still remains to be verified in future studies. An investigation of the effects of an aqueous rhizome extract of T. violacea on Cryptococcus virulence factors showed that phospholipase activity of C. neoformans and C. gattii remained unaffected with increasing sub-lethal doses of the plant extract. There was significant reduction in urease production in both fungi in a dose dependent manner relative to the untreated cultures after 24 hr exposure to the extract. However, urease production reverted to normal after 48 hr post exposure implying that the cultures were able to recover due to temporary inhibition of urease activity. A significant decrease in melanin production was observed in both C. neoformans and C. gattii with increasing sub-inhibitory concentrations of the rhizome extract. Investigation of the effect of the plant extract on the ultrastucture of the fungi via Transmission Electron Microscopy showed the induction of cytomorphological changes in C. neoformans and C. gattii. Changes included thickening of the cell wall, an increase in the number of vacuoles, mitochondrial swelling and occasional detachment of the membrane from the cell wall. These changes suggest the activation of possible defence mechanisms to compensate for the loss of cellular materials or an effort to sequester toxic T. violacea components or toxic intermediates generated from inhibited cellular pathways. The capsule size and architecture remained unaltered in the presence of sub-lethal doses of the rhizome extract. To study the mechanism of action of the rhizome extract on ergosterol biosynthesis, total sterols were extracted and ergosterol, squalene, 2,3-oxidosqualene and lanosterol were quantified using Reverse Phase High Performance Liquid Chromatography. Ergosterol concentration declined in a dose dependent manner for both pathogenic yeasts similar to the positive control terbinafine, while there was a slight accumulation of squalene in C. gattii only. 2,3-oxidosqualene levels accumulated in both fungi relative to the untreated control. Lanosterol production showed an oscillatory trend for the two microorganisms. Together, these findings indicate that the rhizome extract is capable of inhibiting squalene epoxidase and 2,3-oxidosqualene/ lanosterol cyclase causing a decrease in ergosterol production.
- Full Text:
- Date Issued: 2018
- Authors: Mitradev, Pattoo
- Date: 2018
- Subjects: Violaceae -- Therapeutic use -- South Africa , Anticoagulants (Medicine) , Medicinal plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/32772 , vital:32357
- Description: Cryptococcus neoformans and Cryptococcus gattii, which are environmental yeasts, are the etiological agents of cryptococcosis in both immunocompromised and immunocompetent individuals, and account for high mortality and morbidity rates in sub-Saharan Africa. The current antifungal agents used for treatment of cryptococcal infections either target the fungal cell wall (β-(1,3) glucan and chitin) or cell membrane directly or ergosterol biosynthetic pathways or fungal DNA and RNA. Gaps in antifungal therapy include the unavailability and exhorbitant costs of these drugs especially to patients in the developing world. Drug resistance to conventional drugs is also an ever-increasing problem. It is therefore essential to find alternative natural compounds from medicinal plants that are safer, cheaper and more widely available. Tulbaghia violacea, also known as wild garlic, has been used as a traditional remedy in South Africa for the treatment of several ailments. Aqueous and organic extracts of the plant have been demonstrated to have antimicrobial and antifungal activity against several pathogens. However, there is a huge gap in our current knowledge in that the mechanism/s of action/s of these extracts have not been fully investigated. The focus of the current study therefore was to determine whether T. violacea extracts from the roots, rhizome, leaves and tubers exhibited antifungal activity against C. neoformans and C. gattii and to evaluate the ability of the rhizome extract to induce changes in key fungal virulence factors. Three mechanisms (ergosterol, β-(1,3) glucan and chitin production) regulating the antifungal activity of the rhizome extract were also examined. In the current study, phytochemical analysis of aqueous extracts of the roots, leaves, rhizomes and tubers showed that the rhizomes had the highest phenolic, saponin and tannin content when compared to the other plant organs. Fingerprinting by GC-MS revealed identical compounds in the different plant parts with the detection of 4 H Pyran-4-one DDMP (known antifungal), previously unreported in studies on T. violacea. The bulk of the extract comprised of 40% sulphur-containing and 20% furan-containing compounds. The remaining minor compounds comprised of 2x alcohols (13.3%), 1x pyran (6.7%), 1x ketone (6.7%), 1x halogen (6.7%) and 1x acid (6.7%) compounds. The rhizomes also had highest content of 2 methyl methioacetic acid, benzophenone and chloromethyl methylsulfide compared to the other plant parts. The rhizomes were found to be more potent against both pathogenic fungi tested here with an MIC and MFC of 1.25 mg/ml. Nystatin was included as a positive control when determining the MIC’s and MFC’s of the different plant extracts. The antifungal nature of the T. violacea extracts in the current study may be due to the synergistic effects of the sulphide, furan, pyran and ketone compounds present in the extracts, but this still remains to be verified in future studies. An investigation of the effects of an aqueous rhizome extract of T. violacea on Cryptococcus virulence factors showed that phospholipase activity of C. neoformans and C. gattii remained unaffected with increasing sub-lethal doses of the plant extract. There was significant reduction in urease production in both fungi in a dose dependent manner relative to the untreated cultures after 24 hr exposure to the extract. However, urease production reverted to normal after 48 hr post exposure implying that the cultures were able to recover due to temporary inhibition of urease activity. A significant decrease in melanin production was observed in both C. neoformans and C. gattii with increasing sub-inhibitory concentrations of the rhizome extract. Investigation of the effect of the plant extract on the ultrastucture of the fungi via Transmission Electron Microscopy showed the induction of cytomorphological changes in C. neoformans and C. gattii. Changes included thickening of the cell wall, an increase in the number of vacuoles, mitochondrial swelling and occasional detachment of the membrane from the cell wall. These changes suggest the activation of possible defence mechanisms to compensate for the loss of cellular materials or an effort to sequester toxic T. violacea components or toxic intermediates generated from inhibited cellular pathways. The capsule size and architecture remained unaltered in the presence of sub-lethal doses of the rhizome extract. To study the mechanism of action of the rhizome extract on ergosterol biosynthesis, total sterols were extracted and ergosterol, squalene, 2,3-oxidosqualene and lanosterol were quantified using Reverse Phase High Performance Liquid Chromatography. Ergosterol concentration declined in a dose dependent manner for both pathogenic yeasts similar to the positive control terbinafine, while there was a slight accumulation of squalene in C. gattii only. 2,3-oxidosqualene levels accumulated in both fungi relative to the untreated control. Lanosterol production showed an oscillatory trend for the two microorganisms. Together, these findings indicate that the rhizome extract is capable of inhibiting squalene epoxidase and 2,3-oxidosqualene/ lanosterol cyclase causing a decrease in ergosterol production.
- Full Text:
- Date Issued: 2018
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
A biochemical study of the antidiabetic and anticogulant effects of Tulbaghia Violacea
- Authors: Davison, Candice
- Date: 2010
- Subjects: Medicinal plants -- South Africa , Diabetes -- Alternative treatment -- South Africa , Violaceae -- Therapeutic use -- South Africa , Anticoagulants (Medicine) , Plants -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10311 , http://hdl.handle.net/10948/1523 , Medicinal plants -- South Africa , Diabetes -- Alternative treatment -- South Africa , Violaceae -- Therapeutic use -- South Africa , Anticoagulants (Medicine) , Plants -- Analysis
- Description: Secondary metabolites derived from plants, especially those used by traditional healers, are at the forefront of new drug development in combating diseases such as cancer and diabetes. Garlic is employed in indigenous medicine all over the world for the treatment of a variety of diseases. Dietary garlic has been recognized for its beneficial health effects. In particular, garlic consumption has been correlated with (i) reduction of risk factors for cardiovascular diseases and cancer, (ii) stimulation of immune function, (iii) enhanced detoxification of foreign compounds, (iv) hepatoprotection, (v) antimicrobial effects, (vi) antioxidant effects, and most importantly (vii) its hypoglycemic and anticoagulant properties. Due to these beneficial properties, garlic and its closely related genera which includes Tulbaghia violacea, may be useful as coadjuvant therapy in the treatment of type 2 diabetes and some of its physiological complications. The aim of this study was to determine if T. violacea has antidiabetic and anticoagulant properties. This was performed in vitro using both aqueous and organic extracts of the roots, leaves and bulbs. An organic extract was able to improve glucose-stimulated insulin secretion (GSIS) in INS-1 pancreatic β-cells and glucose uptake in Chang liver cells. The BO extract had no effect on the glucose uptake in 3T3-L1 an adipose cell line and reduced glucose utilisation in C2C12, a skeletal muscle cell line. Some of the properties displayed by T. violacea in this study are consistent with those found in similar studies with garlic extracts. It was observed that the BO extract increased the membrane potential and Glut-2 expression in INS-1 cells cultured at hyperglycemic levels, however, at normoglycemic levels a reduction was observed. The oxygen consumption increased at both glycemic levels due to treatment with the BO extract. Platelets were exposed to the extracts to determine their effects upon platelet aggregation, adhesion and protein secretion. Since the BO extract displayed the highest potential at inhibiting platelet aggregation and adhesion. A rat model was used in ex vivo studies to determine if the extract exhibited the same effect in a physiological model. It was noted that the BO extract exhibited a higher degree of inhibition on platelet aggregation and adhesion than the positive control, aspirin. The BO extract reduced clotting times in the prothrombin time (PT) test, but prolonged the clotting time in the actived partial thromboplastin time (APTT) assay in the ex vivo model; however, it had no affect on these clotting assays in the in vitro model using human blood. The BO extract increased the D-dimer and Fibrinogen-C levels in the in vitro model, but had no effect on the D-dimer concentrations and lowered the Fibrinogen-C levels in the ex vivo model. The active compounds in the extract remain to be elucidated.
- Full Text:
- Date Issued: 2010
- Authors: Davison, Candice
- Date: 2010
- Subjects: Medicinal plants -- South Africa , Diabetes -- Alternative treatment -- South Africa , Violaceae -- Therapeutic use -- South Africa , Anticoagulants (Medicine) , Plants -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10311 , http://hdl.handle.net/10948/1523 , Medicinal plants -- South Africa , Diabetes -- Alternative treatment -- South Africa , Violaceae -- Therapeutic use -- South Africa , Anticoagulants (Medicine) , Plants -- Analysis
- Description: Secondary metabolites derived from plants, especially those used by traditional healers, are at the forefront of new drug development in combating diseases such as cancer and diabetes. Garlic is employed in indigenous medicine all over the world for the treatment of a variety of diseases. Dietary garlic has been recognized for its beneficial health effects. In particular, garlic consumption has been correlated with (i) reduction of risk factors for cardiovascular diseases and cancer, (ii) stimulation of immune function, (iii) enhanced detoxification of foreign compounds, (iv) hepatoprotection, (v) antimicrobial effects, (vi) antioxidant effects, and most importantly (vii) its hypoglycemic and anticoagulant properties. Due to these beneficial properties, garlic and its closely related genera which includes Tulbaghia violacea, may be useful as coadjuvant therapy in the treatment of type 2 diabetes and some of its physiological complications. The aim of this study was to determine if T. violacea has antidiabetic and anticoagulant properties. This was performed in vitro using both aqueous and organic extracts of the roots, leaves and bulbs. An organic extract was able to improve glucose-stimulated insulin secretion (GSIS) in INS-1 pancreatic β-cells and glucose uptake in Chang liver cells. The BO extract had no effect on the glucose uptake in 3T3-L1 an adipose cell line and reduced glucose utilisation in C2C12, a skeletal muscle cell line. Some of the properties displayed by T. violacea in this study are consistent with those found in similar studies with garlic extracts. It was observed that the BO extract increased the membrane potential and Glut-2 expression in INS-1 cells cultured at hyperglycemic levels, however, at normoglycemic levels a reduction was observed. The oxygen consumption increased at both glycemic levels due to treatment with the BO extract. Platelets were exposed to the extracts to determine their effects upon platelet aggregation, adhesion and protein secretion. Since the BO extract displayed the highest potential at inhibiting platelet aggregation and adhesion. A rat model was used in ex vivo studies to determine if the extract exhibited the same effect in a physiological model. It was noted that the BO extract exhibited a higher degree of inhibition on platelet aggregation and adhesion than the positive control, aspirin. The BO extract reduced clotting times in the prothrombin time (PT) test, but prolonged the clotting time in the actived partial thromboplastin time (APTT) assay in the ex vivo model; however, it had no affect on these clotting assays in the in vitro model using human blood. The BO extract increased the D-dimer and Fibrinogen-C levels in the in vitro model, but had no effect on the D-dimer concentrations and lowered the Fibrinogen-C levels in the ex vivo model. The active compounds in the extract remain to be elucidated.
- Full Text:
- Date Issued: 2010
- «
- ‹
- 1
- ›
- »