Bioactivity and phytochemical analysis of Hydnora Africana on some selected bacterial pathogens
- Authors: Nethathe, Bono Bianca
- Date: 2011
- Subjects: Helicobacter pylori , Medicinal plants -- South Africa -- Eastern Cape , Microbial sensitivity tests , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Plants -- Analysis , Staphylococcus aureus , Aeromonas hydrophila , Drug resistance in microorganisms , Plant-pathogen relationships
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11247 , http://hdl.handle.net/10353/d1001063 , Helicobacter pylori , Medicinal plants -- South Africa -- Eastern Cape , Microbial sensitivity tests , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Plants -- Analysis , Staphylococcus aureus , Aeromonas hydrophila , Drug resistance in microorganisms , Plant-pathogen relationships
- Description: Abstract Medicinal plants have been for long remedies for human diseases because they contain components of therapeutic value. The growing problem of antibiotic resistance by organisms demands the search for novel compounds from plant based sources. The present study was aimed at evaluating the bioactivity and phytochemical analysis of Hydnora africana on clinical and standard strains of Helicobacter pylori (PE 252C and ATCC 43526), Aeromonas hydrophila ATCC 35654, and Staphylococcus aureus NCT 6571 in an effort to identify potential sources of cheap starting materials for the synthesis of new drugs against these strains. Ethyl acetate, acetone, ethanol, methanol, and water crude extracts of H. africana were screened for activity against the test organisms using the agar well diffusion assay. The Minimum Inhibitory Concentration (MIC50) and Minimum Bactericidal Concentration (MBC) of the most potent extracts were determined by the microdilution method, followed by qualitative phytochemical analysis. Results were analyzed statistically by ANOVA one - way test. Different concentrations (200,100, 50mg/mL) of the methanol, acetone, ethanol and ethyl acetate extracts showed activity against S. aureus and A. hydrophila while for H. pylori, only methanol and ethyl acetate extracts were active; water showed no activity for all studied bacterial pathogens. Mean zone diameter of inhibition which ranged from 0-22mm were observed for all test bacterial pathogens and 14-17mm for ciprofloxacin. The activity of methanol and ethyl acetate extracts were statistically significant (P< 0.05) compared to all the other extracts. MIC50 and MBC ranged from 0.078 – 2.5mg/mL, 0.78-25mg/mL respectively for all tested bacterial pathogens. For ciprofloxacin, the MIC50 and MBC ranged from 0.00976 – 0.078mg/mL and 0.098– 0.78mg/mL respectively. There was no statistically significant difference between extracts (methanol, acetone, ethanol, ethyl acetate) and the control antibiotic (ciprofloxacin) (P> 0.05). Qualitative phytochemical analysis confirmed the presence of alkaloids, saponins, steroids, tannins and flavonoids in the methanol, acetone,ethanol and ethyl acetate extracts. The results demonstrate that H. africana may contain compounds with therapeutic potentials which can be lead molecules for semi-synthesis of new drugs.
- Full Text:
- Date Issued: 2011
- Authors: Nethathe, Bono Bianca
- Date: 2011
- Subjects: Helicobacter pylori , Medicinal plants -- South Africa -- Eastern Cape , Microbial sensitivity tests , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Plants -- Analysis , Staphylococcus aureus , Aeromonas hydrophila , Drug resistance in microorganisms , Plant-pathogen relationships
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11247 , http://hdl.handle.net/10353/d1001063 , Helicobacter pylori , Medicinal plants -- South Africa -- Eastern Cape , Microbial sensitivity tests , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Plants -- Analysis , Staphylococcus aureus , Aeromonas hydrophila , Drug resistance in microorganisms , Plant-pathogen relationships
- Description: Abstract Medicinal plants have been for long remedies for human diseases because they contain components of therapeutic value. The growing problem of antibiotic resistance by organisms demands the search for novel compounds from plant based sources. The present study was aimed at evaluating the bioactivity and phytochemical analysis of Hydnora africana on clinical and standard strains of Helicobacter pylori (PE 252C and ATCC 43526), Aeromonas hydrophila ATCC 35654, and Staphylococcus aureus NCT 6571 in an effort to identify potential sources of cheap starting materials for the synthesis of new drugs against these strains. Ethyl acetate, acetone, ethanol, methanol, and water crude extracts of H. africana were screened for activity against the test organisms using the agar well diffusion assay. The Minimum Inhibitory Concentration (MIC50) and Minimum Bactericidal Concentration (MBC) of the most potent extracts were determined by the microdilution method, followed by qualitative phytochemical analysis. Results were analyzed statistically by ANOVA one - way test. Different concentrations (200,100, 50mg/mL) of the methanol, acetone, ethanol and ethyl acetate extracts showed activity against S. aureus and A. hydrophila while for H. pylori, only methanol and ethyl acetate extracts were active; water showed no activity for all studied bacterial pathogens. Mean zone diameter of inhibition which ranged from 0-22mm were observed for all test bacterial pathogens and 14-17mm for ciprofloxacin. The activity of methanol and ethyl acetate extracts were statistically significant (P< 0.05) compared to all the other extracts. MIC50 and MBC ranged from 0.078 – 2.5mg/mL, 0.78-25mg/mL respectively for all tested bacterial pathogens. For ciprofloxacin, the MIC50 and MBC ranged from 0.00976 – 0.078mg/mL and 0.098– 0.78mg/mL respectively. There was no statistically significant difference between extracts (methanol, acetone, ethanol, ethyl acetate) and the control antibiotic (ciprofloxacin) (P> 0.05). Qualitative phytochemical analysis confirmed the presence of alkaloids, saponins, steroids, tannins and flavonoids in the methanol, acetone,ethanol and ethyl acetate extracts. The results demonstrate that H. africana may contain compounds with therapeutic potentials which can be lead molecules for semi-synthesis of new drugs.
- Full Text:
- Date Issued: 2011
The efficacy and toxicological effects of aloe ferox mill. used in the management of constipation in Nkonkobe municipality of the Eastern Cape province, South Africa
- Authors: Wintola, Olubunmi Abosede A
- Date: 2011
- Subjects: Asphodelaceae -- South Africa -- Eastern Cape , Aloe -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Constipation -- South Africa -- Eastern Cape , Poisonous plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Ethnobotany)
- Identifier: vital:11882 , http://hdl.handle.net/10353/485 , Asphodelaceae -- South Africa -- Eastern Cape , Aloe -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Constipation -- South Africa -- Eastern Cape , Poisonous plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Description: Herbal remedies are commonly used in developing countries for the treatment of various diseases, including constipation. The rationale for utilizing medicinal plants for the treatment of diseases rested largely on the belief that they are safe and free of side effects. However, there is limited scientific evidence on the safety and efficacy of these herbal medicines to back up their continued therapeutic application. Aloe ferox Mill. (Aspodelaceae), known as Cape aloe, locally called ikhala is a medicinal plant used by the people of the Eastern Cape Province for the treatment of gastrointestinal problems and constipation. The plant is a perennial shrub with thick succulent leaves bearing brown thorns on the margin and bright orange flowers arranged in oval lanceolate. It occurs in all weather in bush veld, road side, gardens and undisturbed places. According to the ethnomedicinal information, A. ferox is used as purgative. This research project was therefore designed to evaluate its ability in the treatment of constipation and to investigate its possible toxicological property. At the beginning of this programme, a survey of plants used for the treatment of constipation in Nkonkobe Municipality of the Eastern Cape Province was carried out using a questionnaire, which was administered to herbalists, traditional healers and rural dwellers. The study revealed 10 plant species from 8 families that are used for the treatment of constipation in the province. Four plants, Aloe ferox Mill, Boophone distischa L.f Herb, Alepidea amatybica Eckl and Artemisia afra Jacq, were repeatedly mentioned. Based on the frequency of usage, perceived efficacy and availability to the rural dwellers and the traditional healers, Aloe ferox was the most commonly used of the plants for the treatment of constipation. The plant was thus, chosen for the study. The invivo laxative effect of the aqueous extract of Aloe ferox in the treatment of loperamide-induced constipation in Wistar rats was investigated at varying concentrations. The leaf extract at all the dosages investigated (50, 100 and 200 mg/kg body weight) improved intestinal motility, increased fecal volume and normalized body weight in the constipated rats. This was an indication of its laxative properties. However, the laxative property of the herb at 200 mg/kg body weight of the extract showed best efficacy and compares favourably well with senokot, a standard laxative drug. These findings have therefore, lent scientific credence to the folkloric use of the herb by the people of the Eastern Cape of South Africa as a laxative agent. Toxicological evaluation of aqueous leaf extract of Aloe ferox in loperamide-induced constipation was studied at 50, 100, and 200 mg/kg body weight. The oral administration of the extracts did not show any significant effect on the liver and kidney body weight ratios as well as the kidney and liver function indices. The extracts, at all the dosages investigated, did not alter the levels of creatinine, uric acid, urea, calcium and potassium ions. Similarly, the levels of total protein, albumin, bilirubin and gamma glutamyl transferase (GGT) were not significantly different from the control. The plant extract appreciably normalized the elevated activities of alkaline phosphatase (ALP), alanine transaminase (ALT) and aspartate transaminase (AST) in the untreated constipated rats following treatment with the extract. The extract did not show a significant effect on the hematological parameters except for the increase in the lymphocyte count in the untreated constipated rats, which was attenuated after administering the herb. ThThe available evidence in this study suggests that A. ferox may be safe as an oral remedy for constipation. Generally, the effect of the extract compared favourably well with senokot, a recommended drug for the treatment of constipation. The antioxidant activities against 1, 1 diphenyl- 2 picrylhydrazl (DPPH), 2,2’ – azinobis [3- ethylbenzothiazoline -6- sulfonic acid] diammonium salt (ABTS), hydrogen peroxide (H2O2), Nitric oxide (NO), lipid peroxidation and the ferric reducing agents were investigated spectrophotometrically. Alkaloids, saponins, tannins, total phenols, flavonoids, flavonols and proanthocyanidin were also determined to assess their effects on the antioxidants activity of this plant. The phytochemical content of the ethanol and acetone extracts were consistently high compared to other solvents extracts. The level of tannins was not significant (P > 0.05) as compared with other solvent extracts. The free radical scavenging activity of the extracts was high even at lower concentrations (0.025 mg/ml) except in DPPH and lipid peroxidation. The ferric reducing potential of the extracts was concentration dependent and significantly different from Vitamin C and butylated hydroxytoluene (BHT) that were used as standard drugs. The present study showed a high level of scavenging activity of the leaf extracts of Aloe ferox in all the solvent extracts. Both ethanol and methanolic extract showed potent antioxidant activities than acetone and aqueous extracts. The study indicated that the leaf extracts of Aloe ferox might be a valuable source of natural antioxidant for both medicine and food industries. A. ferox leaf consists of the gel, latex and mesophyll layer; however, the main active constituents of the latex and the leaf exudate of Aloe ferox are anthraquinones which are believed to be responsible for the laxative property. The laxative compound in Aloe ferox leaf extract was isolated and characterized by extracting the plant material in methanol and extract suspended in distilled water. Partitioning was done with n-hexane, ethyl acetate and butanol respectively and was co-spotted with the over-the-counter (OTC) laxative drugs. This led to the successive column chromatography and thin layer chromatography (TLC) of the most active ethyl acetate fraction on silica gel with benzene/ethanol/ammonia hydroxide (BEA: 90:10:1), ethyl acetate/methanol/water (EMW: 40:5.4:5) and chloroform/ethyl acetate/formic acid (CEF: 50:40:10) as the mobile phase. The successive chromatograph and TLC afforded two compounds of Rf 0.420 (blue) and 0.831 (yellow) with the over-the-counter (OTC) drugs. These compounds were not totally elucidated due to their small quantity and instability. However, hydroxyl (OH) and carboxyl groups (COOH) was established as common to the extracted compounds, which might be responsible for the biological activity recorded for the plant extract.
- Full Text:
- Date Issued: 2011
- Authors: Wintola, Olubunmi Abosede A
- Date: 2011
- Subjects: Asphodelaceae -- South Africa -- Eastern Cape , Aloe -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Constipation -- South Africa -- Eastern Cape , Poisonous plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Ethnobotany)
- Identifier: vital:11882 , http://hdl.handle.net/10353/485 , Asphodelaceae -- South Africa -- Eastern Cape , Aloe -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Constipation -- South Africa -- Eastern Cape , Poisonous plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Description: Herbal remedies are commonly used in developing countries for the treatment of various diseases, including constipation. The rationale for utilizing medicinal plants for the treatment of diseases rested largely on the belief that they are safe and free of side effects. However, there is limited scientific evidence on the safety and efficacy of these herbal medicines to back up their continued therapeutic application. Aloe ferox Mill. (Aspodelaceae), known as Cape aloe, locally called ikhala is a medicinal plant used by the people of the Eastern Cape Province for the treatment of gastrointestinal problems and constipation. The plant is a perennial shrub with thick succulent leaves bearing brown thorns on the margin and bright orange flowers arranged in oval lanceolate. It occurs in all weather in bush veld, road side, gardens and undisturbed places. According to the ethnomedicinal information, A. ferox is used as purgative. This research project was therefore designed to evaluate its ability in the treatment of constipation and to investigate its possible toxicological property. At the beginning of this programme, a survey of plants used for the treatment of constipation in Nkonkobe Municipality of the Eastern Cape Province was carried out using a questionnaire, which was administered to herbalists, traditional healers and rural dwellers. The study revealed 10 plant species from 8 families that are used for the treatment of constipation in the province. Four plants, Aloe ferox Mill, Boophone distischa L.f Herb, Alepidea amatybica Eckl and Artemisia afra Jacq, were repeatedly mentioned. Based on the frequency of usage, perceived efficacy and availability to the rural dwellers and the traditional healers, Aloe ferox was the most commonly used of the plants for the treatment of constipation. The plant was thus, chosen for the study. The invivo laxative effect of the aqueous extract of Aloe ferox in the treatment of loperamide-induced constipation in Wistar rats was investigated at varying concentrations. The leaf extract at all the dosages investigated (50, 100 and 200 mg/kg body weight) improved intestinal motility, increased fecal volume and normalized body weight in the constipated rats. This was an indication of its laxative properties. However, the laxative property of the herb at 200 mg/kg body weight of the extract showed best efficacy and compares favourably well with senokot, a standard laxative drug. These findings have therefore, lent scientific credence to the folkloric use of the herb by the people of the Eastern Cape of South Africa as a laxative agent. Toxicological evaluation of aqueous leaf extract of Aloe ferox in loperamide-induced constipation was studied at 50, 100, and 200 mg/kg body weight. The oral administration of the extracts did not show any significant effect on the liver and kidney body weight ratios as well as the kidney and liver function indices. The extracts, at all the dosages investigated, did not alter the levels of creatinine, uric acid, urea, calcium and potassium ions. Similarly, the levels of total protein, albumin, bilirubin and gamma glutamyl transferase (GGT) were not significantly different from the control. The plant extract appreciably normalized the elevated activities of alkaline phosphatase (ALP), alanine transaminase (ALT) and aspartate transaminase (AST) in the untreated constipated rats following treatment with the extract. The extract did not show a significant effect on the hematological parameters except for the increase in the lymphocyte count in the untreated constipated rats, which was attenuated after administering the herb. ThThe available evidence in this study suggests that A. ferox may be safe as an oral remedy for constipation. Generally, the effect of the extract compared favourably well with senokot, a recommended drug for the treatment of constipation. The antioxidant activities against 1, 1 diphenyl- 2 picrylhydrazl (DPPH), 2,2’ – azinobis [3- ethylbenzothiazoline -6- sulfonic acid] diammonium salt (ABTS), hydrogen peroxide (H2O2), Nitric oxide (NO), lipid peroxidation and the ferric reducing agents were investigated spectrophotometrically. Alkaloids, saponins, tannins, total phenols, flavonoids, flavonols and proanthocyanidin were also determined to assess their effects on the antioxidants activity of this plant. The phytochemical content of the ethanol and acetone extracts were consistently high compared to other solvents extracts. The level of tannins was not significant (P > 0.05) as compared with other solvent extracts. The free radical scavenging activity of the extracts was high even at lower concentrations (0.025 mg/ml) except in DPPH and lipid peroxidation. The ferric reducing potential of the extracts was concentration dependent and significantly different from Vitamin C and butylated hydroxytoluene (BHT) that were used as standard drugs. The present study showed a high level of scavenging activity of the leaf extracts of Aloe ferox in all the solvent extracts. Both ethanol and methanolic extract showed potent antioxidant activities than acetone and aqueous extracts. The study indicated that the leaf extracts of Aloe ferox might be a valuable source of natural antioxidant for both medicine and food industries. A. ferox leaf consists of the gel, latex and mesophyll layer; however, the main active constituents of the latex and the leaf exudate of Aloe ferox are anthraquinones which are believed to be responsible for the laxative property. The laxative compound in Aloe ferox leaf extract was isolated and characterized by extracting the plant material in methanol and extract suspended in distilled water. Partitioning was done with n-hexane, ethyl acetate and butanol respectively and was co-spotted with the over-the-counter (OTC) laxative drugs. This led to the successive column chromatography and thin layer chromatography (TLC) of the most active ethyl acetate fraction on silica gel with benzene/ethanol/ammonia hydroxide (BEA: 90:10:1), ethyl acetate/methanol/water (EMW: 40:5.4:5) and chloroform/ethyl acetate/formic acid (CEF: 50:40:10) as the mobile phase. The successive chromatograph and TLC afforded two compounds of Rf 0.420 (blue) and 0.831 (yellow) with the over-the-counter (OTC) drugs. These compounds were not totally elucidated due to their small quantity and instability. However, hydroxyl (OH) and carboxyl groups (COOH) was established as common to the extracted compounds, which might be responsible for the biological activity recorded for the plant extract.
- Full Text:
- Date Issued: 2011
Biological activities of medicinal plants traditionally used to treat Septicaemia in the Eastern Cape, South Africa
- Authors: Chinyama, Robert Fred
- Date: 2009
- Subjects: Materia medica, Vegetable -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10119 , http://hdl.handle.net/10948/1274 , Materia medica, Vegetable -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape
- Description: Over the past 25 years, there has been a resurgence of worldwide scientific research in the fields of ethnopharmacology. The Western world has acknowledged the continued use of traditional medicines by the majority of third world countries, and the need for novel drug development. Hence, much of the pharmaceutical research in recent years has focused on the ethnobotanical approach to drug discovery (Light et al., 2005). In South Africa, as in most developing parts of the world, traditional herbal medicine still forms the backbone of rural healthcare. The government health services in South Africa provide only western medical care although the majority of the population consult traditional healers for some or all of their healthcare needs (McGaw et al., 2005). Medicinal plants like Harpephyllum caffrum are used as blood purifiers or emetics (Watt and Breyer-Brandwijk, 1962), and also for treating acne and eczema. The antimicrobial activity of this plant can be used to treat septicaemia, which is ranked the sixth leading cause of death among neonates and the eighth leading cause of death for infants through the first year of life (Heron, 2007). In this study, the plants investigated for antimicrobial activity were Harpephyllum caffrum, Hermannia cuneifolia, Chironia baccifera, Rhigozum obovatum, Felicia muricata and Pentzia incana. These plants were tested against ATTC (American Type Culture Collection) strains and microorganisms isolated from clinical isolates of patients suffering from septicaemia. The assay methods used included the agar diffusion method using the Mast multipoint inoculator, the microtitre dilution method were used to determine the minimum inhibitory concentration, thin layer chromatography fingerprints accompanied by bioautographic assay were used to detect the inhibition of bacterial growth by active compounds separated from plant extracts and the Ames test was required to assess the possibility of bacterial mutagenesis upon the exposure to plant extracts which can lead to carcinogenicity. In agar diffusion method, extracts of Harpephyllum caffrum inhibited nine strains of Candida albicans, three species of Acinetobacter and four strains of E.faecalis. Extracts of Hermannia cuneifolia inhibited four strains of B.cereus and three strains of Staphylococcus aureus. Extracts of Chironia baccifera inhibited one strain of Acinetobacter and five strains of E.faecalis. Extracts of plants Rhigozum obovatum, Felicia muricata, and Pentzia incana showed no antimicrobial activity. In the microtitre dilution method used to determine the minimum inhibitory concentration (MIC), the results were different from the agar diffusion method. More activity was observed. Extracts of Harpephyllum caffrum inhibited three strains of E.coli, six strains of S.aureus, three species of Acinetobacter and one strain of Klebsiella pneumonia. Extracts of Hermannia cuneifolia inhibited four strains of B.cereus, three strains of S.aureus, two strains of K.oxytoca and one species of Acinetobacter. Extracts of Chironia baccifera inhibited three strains of S.aureus, one strain of MRSA, one species of Acinetobacter and one strain of S.haemolyticus. The MIC values ranged from 0.049 to 6.25mg/ml. Using the thin layer chromatography fingerprints, bioautography showed the presence of various inhibitory chemical compounds. Methanol and acetone extracts of Harpephyllum caffrum, separated very well and showed various inhibition zones on exposure to Candida albicans, Enterococcus faecalis and Staphylococcus aureus. The different inhibition zones were recorded as Rf In the Ames test (Maron and Ames, 1983) the methanol and acetone extracts of Harpephyllum caffrum and Hermannia cuneifolia were negative which means they were devoid of any mutagenic properties. Methanol extracts of Harpephyllum caffrum showed similar results in the Ames assay as reported by Verschaeve and Van Staden (2008). values ranging from 0.25 to 0.95. The zones indicate the different inhibiting chemical compounds present in the plant. Petroleum ether, ethyl acetate, chloroform and formic acid were the solvents used in the assay in the ratio 8:7:5:1, respectively. Establishing the antimicrobial activity of these plants contribute to the systematic scientific investigation of indigenous South African medicinal plants.
- Full Text:
- Date Issued: 2009
- Authors: Chinyama, Robert Fred
- Date: 2009
- Subjects: Materia medica, Vegetable -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10119 , http://hdl.handle.net/10948/1274 , Materia medica, Vegetable -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape
- Description: Over the past 25 years, there has been a resurgence of worldwide scientific research in the fields of ethnopharmacology. The Western world has acknowledged the continued use of traditional medicines by the majority of third world countries, and the need for novel drug development. Hence, much of the pharmaceutical research in recent years has focused on the ethnobotanical approach to drug discovery (Light et al., 2005). In South Africa, as in most developing parts of the world, traditional herbal medicine still forms the backbone of rural healthcare. The government health services in South Africa provide only western medical care although the majority of the population consult traditional healers for some or all of their healthcare needs (McGaw et al., 2005). Medicinal plants like Harpephyllum caffrum are used as blood purifiers or emetics (Watt and Breyer-Brandwijk, 1962), and also for treating acne and eczema. The antimicrobial activity of this plant can be used to treat septicaemia, which is ranked the sixth leading cause of death among neonates and the eighth leading cause of death for infants through the first year of life (Heron, 2007). In this study, the plants investigated for antimicrobial activity were Harpephyllum caffrum, Hermannia cuneifolia, Chironia baccifera, Rhigozum obovatum, Felicia muricata and Pentzia incana. These plants were tested against ATTC (American Type Culture Collection) strains and microorganisms isolated from clinical isolates of patients suffering from septicaemia. The assay methods used included the agar diffusion method using the Mast multipoint inoculator, the microtitre dilution method were used to determine the minimum inhibitory concentration, thin layer chromatography fingerprints accompanied by bioautographic assay were used to detect the inhibition of bacterial growth by active compounds separated from plant extracts and the Ames test was required to assess the possibility of bacterial mutagenesis upon the exposure to plant extracts which can lead to carcinogenicity. In agar diffusion method, extracts of Harpephyllum caffrum inhibited nine strains of Candida albicans, three species of Acinetobacter and four strains of E.faecalis. Extracts of Hermannia cuneifolia inhibited four strains of B.cereus and three strains of Staphylococcus aureus. Extracts of Chironia baccifera inhibited one strain of Acinetobacter and five strains of E.faecalis. Extracts of plants Rhigozum obovatum, Felicia muricata, and Pentzia incana showed no antimicrobial activity. In the microtitre dilution method used to determine the minimum inhibitory concentration (MIC), the results were different from the agar diffusion method. More activity was observed. Extracts of Harpephyllum caffrum inhibited three strains of E.coli, six strains of S.aureus, three species of Acinetobacter and one strain of Klebsiella pneumonia. Extracts of Hermannia cuneifolia inhibited four strains of B.cereus, three strains of S.aureus, two strains of K.oxytoca and one species of Acinetobacter. Extracts of Chironia baccifera inhibited three strains of S.aureus, one strain of MRSA, one species of Acinetobacter and one strain of S.haemolyticus. The MIC values ranged from 0.049 to 6.25mg/ml. Using the thin layer chromatography fingerprints, bioautography showed the presence of various inhibitory chemical compounds. Methanol and acetone extracts of Harpephyllum caffrum, separated very well and showed various inhibition zones on exposure to Candida albicans, Enterococcus faecalis and Staphylococcus aureus. The different inhibition zones were recorded as Rf In the Ames test (Maron and Ames, 1983) the methanol and acetone extracts of Harpephyllum caffrum and Hermannia cuneifolia were negative which means they were devoid of any mutagenic properties. Methanol extracts of Harpephyllum caffrum showed similar results in the Ames assay as reported by Verschaeve and Van Staden (2008). values ranging from 0.25 to 0.95. The zones indicate the different inhibiting chemical compounds present in the plant. Petroleum ether, ethyl acetate, chloroform and formic acid were the solvents used in the assay in the ratio 8:7:5:1, respectively. Establishing the antimicrobial activity of these plants contribute to the systematic scientific investigation of indigenous South African medicinal plants.
- Full Text:
- Date Issued: 2009
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