South African Herbal Science and Medicine Institute (SAHSMI)
Permanent URI for this community
Browse
Browsing by Issue Date
Now showing 1 - 20 of 24
Results Per Page
Sort Options
Item Synergistic effects of mixtures of the kresoxim-methyl fungicide and medicinal plants extracts in vitro and in vivo against Botrytis Cinerea(University of the Western Cape, 2005) Knowles, Cindy-Lee; Klaasen, J.A; Johnson, Q; Dept. of Medical BioSciences; Faculty of ScienceThe fungus Botrytis cinerea is an opportunistic pathogen on a wide variety of crops, causing disease known as grey mould through infections via wounds or dead plant parts. Synthetic fungicides for controlling this disease are fast becoming ineffective due to the development of resistance. This, coupled with consumers world wide becomng increasingly conscious of potential environment and health problems associated with the build up of toxic chemicals, (particularly in food products), have resulted in pressure to reduce the use of chemical pesticide volumes as well as its residues. An emerging alternative to random synthesis is the study and exploitation of naturally occurring products with fungicidal properties. There have been reports on the uses of synthetic fungicides for the control of plant pathogenic fungi. When utilized in two-way mixtures, such fungicides may maintain or enhance the level of control of a pathogen at reduced rates for both components utilized in combinations, or alone at normal rates. For this study it was hypothesize that the addition of plant extracts may enhance the antifungal efficacy of the synthetic strobilurin fungicide, kresoxim-methyl against Botrytis cinerea.Item Synergistic effects of mixtures of the kresoxim-methyl fungicide and medicinal plant extracts in vitro and in vivo against Botrytis cinerea(University of the Western Cape, 2005) Knowles, Cindy-Lee; Klaasen, J.; Johnson, Q.The fungus Botrytis cinerea is an opportunistic pathogen on a wide variety of crops, causing a disease known as grey mould through infections via wounds or dead plant parts. Synthetic fungicides for controlling this disease are fast becoming ineffective due to the development of resistance. This, coupled with consumers' world wide becoming increasingly conscious of potential environmental and health problems associated with the build-up of toxic chemicals, (particularly in food products), have resulted in pressure to reduce the use of chemical pesticide volumes as well as its residues. An emerging alternative to random chemical synthesis is the study and exploitation of naturally occurring products with fungicidal properties. One group of compounds known as strobilurins produced by Strobilurus species, woodland basidiomycete fungi, is a good example of this phenomenon. Plants produce an enormous array of secondary metabolites, and it is commonly reasoned that a significant part of this chemical diversity serves to protect plants against plant pathogens. A problem with plant-produced compounds as potential fungicides is that in the natural state, they are generally only weakly active compared to synthetic fungicides. There have been reports on the uses of mixtures of synthetic fungicides for the control of plant pathogenic fungi. When utilized in two-way mixtures, such fungicides may maintain or enhance the level of control of a pathogen at reduced rates for both components utilized in combinations, or alone at normal rates. These studies provide an important precedent for the idea of synergism. For this study, we hypothesize that the addition of plant extracts may enhance the antifungal efficacy of the synthetic strobilurin fungicide, kresoxim-rnethyl against B. cinerea. We selected South African medicinal plant species such as Artemesia afra, Elyptropappus rhinocerotis, Galenia africana, Hypoxis hemerocallidea, Siphonochilus aetheopicus, Sutherlundia frutescence, Tulbaghia violacea and Tulbaghia alliaceae for this study. For the in vitro study, indigenous medicinal plant extracts were prepared at twofold dilution concentrations and combined with kresoxim-rnethyl at concentrations of 0.25 and 0.5% (w/v). The B. cinerea mycelial plug assays showed potent antifungal inhibitory effects with the plant extract and kresoxim-rnethyl mixtures. Further analyses of the mixtures indicate synergistic effects between the fungicide and plant extracts. I surmise that these in vitro effects are also achievable in vivo. Combinations of these agents represent an attractive avenue for the development of new management strategies for controlling B. cinerea in the future. A second study was conducted to analyse the final dose rates for synergistic reactions for combinations of kresoxim-methyl and medicinal plant extracts against B. cinerea in vivo. A series of two-fold concentrations of medicinal plant extracts were combined with kresoxim-methyl to conduct decay inhibition studies on Granny Smith apples. Synergistic effects were observed for many of the kresoxim-methyl and plant extract combinations. I, therefore, came to the conclusion that indigenous South African plant species produce modulators that potentiate the activity of fungicides. Whether these synergistic effects are due to the inhibition of fungal multi-drug resistant pumps require further studies at the molecular level. However, these inhibitory effects are likely to be advantageous for developing fungicide formulations and application strategies with low toxicity effects on the environment. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.Item An assessment of medicinal hemp plant extracts as natural antibiotic and immune modulation phytotherapies(University of the Western Cape, 2005) Case, Olivia Hildegard; Dept. of Medical BioSciences; Faculty of ScienceThis study aimed to evaluate the antimicrobial efficacy of medicinal hemp plant extracts to determine the antibacterial effects of indigenous Sansevieria species and exotic Cannabis sativa phytotherapy varieties. This study also assessed whether aqueous oItem An assessment of Hypoxis hemerocallidea extracts, and actives as natural antibiotic, and immune modulation phytotherapies(University of the Western Cape, 2006) Muwanga, Catherine; Johnson, Quinton; South African Herbal Science and Medicine Institute (SAHSMI); Faculty of ScienceIn South Africa, the crude aqueous extract from Hypoxis hemerocallidea is used by AIDS patients to treat opportunistic infections, such as tuberculosis. The rapid emergence of multidrug-resistant tuberculosis, and extreme drug resistant tuberculosis, in recent years, is a major threat to human health. The treatment of TB, nosocomial bacterial infections, and fungal infections is now a clinical challenge, especially in the immuno-compromised individual. There is a dire need for novel antibiotic alternatives with phytotherapies and plant-derived compounds as potentially promising alternatives. The main objective of this study was to investigate the antimycobacterial activity of Hypoxis hemerocallidea, a South African medicinal plant, using Mycobacterium smegmatis.Item Isolation and Characterization of Natural Products from Siphonochilus aethiopicus(University of the Western Cape, 2009) Ndiitwani, Dowelani Clement; Mabusela, W.T.Plants have formed the basis of traditional medicinal systems that have been in existence for thousands of years. Traditional medicines play an important role in protecting, maintaining and restoring the health of people. Therefore, information on folk medicinal uses of plants has in latter times received an intense renewed interest as a source in the search for potential new therapeutic agents. The aim of this study was to isolate and identify natural compounds from Siphonochilus aethiopicus which is a species from the Zingiberaceae family and is one of the most popular medicinal plants in South Africa. This species is used extensively in traditional African medicine for pain relief, asthma, coughs, colds, headaches, dysmenorrhoea and influenza. Extraction of leaves and rhizomes were performed sequentially with hexane, dichloromethane, ethyl acetate, methanol and water. The presences of organic compounds were screened using chromatogtaphic techniques. The screening revealed similarities between the leaves and rhizomes extracts which implies that in order to improve the sustainability of the plants only leaves need to be harvested. All HPLC chromatograms except for the methanol extract of leaves have shown prominent peak. Moreover, the HPLC results confirm that same compounds are present in both leaves and rhizomes. The antimicrobial activity of the rhizome aqueous extract was carried out against Gram positive (Staphylococcus aureus, Mycobacterium smegmatis) and Gram negative (Pseudomonas aeruginosa) bacteria as well as fungus (Candida albicans). GC NMR and MS techniques were used for structural elucidation.Item Use of antioxidant activity and flavonoid levels to assess the quality of commercially available solid dose Sutherlandia frutescens products(University of the Western Cape, 2010) Hess, Meggan Sade; Syce, James; South African Herbal Science and Medicine Institute (SAHSMI); Faculty of ScienceThe overall aims of this project were to assess the pharmaceutical quality and consistency of commercially available solid dose Sutherlandia frutescens containing products (viz. tablets & capsules) by exploring the use of monitoring the pharmaceutical presentation, flavonoid profile and antioxidant activity levels and to develop/or adapt methods and specifications that may be used for the quality control of such products.Stability tests were conducted on all of the selected SCP. The products were stored under elevated temperatures and environmental humidity conditions and total phenol, antioxidant and chromatographic analysis was conducted on these samples. Samples of each of the SCP were hydrolyzed using HCL and then analyzed using HPLC to test the stability of the flavonoids present in each product. The SCP investigated in this study physically appeared to be of quite good “pharmaceutical” quality, but generally lacked information on the date of manufacture and lacked package inserts, or when these were present they contained insufficient information. Based on the results obtained, it is recommended that, the manufacturers of SCP pay more attention to the information provided on the package inserts and the storage conditions for their products. Further the levels of antioxidant activity, total phenols and flavonoid (sutherlandins A to D) be used as specifications to control the quality of commercially available solid dose Sutherlandia frutescens containing preparations on an individual basis.Item The immune-modulating activity of Sutherlandia frutescens(University of the Western Cape, 2010) Kisten, Najwa; Pool, Edmund J.; NULL; Faculty of ScienceThe aim of this study was to investigate the effects of Sutherlandia frutescens on the inflammatory response and T cell differentiation in vitro using cytokines as biomarkers. Whole blood cells containing various concentrations of Sutherlandia frutescens were stimulated in vitro with either Lipopolysaccharide (LPS) or Phytohaemagglutinin (PHA). Results show that Sutherlandia frutescens is not toxic at any of the concentrations tested. The addition of Sutherlandia frutescens at high concentrations to the stimulated whole blood cell cultures reflects a significant down regulation of Interleukin(IL) 6 and IL-10 compared to the control (P<0.05) hence suppressed the inflammatory and humoral immune response. Results obtained for Inteferon-gamma (IFN ) shows that Sutherlandia frutescens is donor specific as it reflects both up and down regulation in the release of IFN at the concentrations tested. The in vitro data generated by this study supports the use of Sutherlandia frutescens in the management of inflammatory conditions and allergies such as asthma. However the effects of Sutherlandia frutescens on cell mediated immunity was found to be donor specific. Further investigation of Sutherlandia frutescens on cellular immunity is advised.Item The immune-modulating activity of Artemisia afra(University of the Western Cape, 2010) Kriel, Yusra; Pool, Edmund J.; Faculty of ScienceThis study shows that herbs can be effectively screened for potiential bio-activity using in vitro methods. Further studies will be needed to better explore Artemisia afra’s effect on immunoregulation, particularly long term effects of the herb on the immune system and its effect on other disease states.Item Phytochemical screening and biological activity studies of five South African indigenous medicinal plants(Academic Journals, 2010) Babajide, Jelili Olalekan; Mabusela, Wilfred T.; Green, Ivan; Ameer, Farouk; Weitz, Frans; Iwuoha, Emmanuel I.Different extracts and fractions of five selected indigenous South African medicinal plants, namely, Cissampelos capensis, Geranium incanum and three Gethyllis species, were subjected to phytochemical screening and testing for cytotoxicity using the brine shrimp lethality bioassay, and antimicrobial activity assays against nine microbes, which included three fungal species, three Gram negative and three Gram positive bacteria.The majority of the extracts tested positive for the presence of tannins, phenolics and flavonoids, while in selected cases, phytochemical tests suggested the presence of essential oils, glycosides or alkaloids. The methanol extract of Gethyllis gregoriana displayed the highest cytotoxicity levels. Generally, the highest levels of biological activity were shown to reside in the methanolic extracts, while hexane extracts revealed very low to zero activity. The total tertiary alkaloid (TTA) of C. capensis was mostly active against Bacillus subtilis, a Gram +ve bacteria. The trends observed for the cytotoxicity assay were in agreement with those observed for the antimicrobial assay.Item Effects of environmental growth conditions on the levels of sutherlandins 3 and 4 and sutherlandiosides B and D, in Sutherlandia frutescens (L.) R. Br.(University of the Western Cape, 2011) Whisgary, Darryn; Syce, James A.Sutherlandia frutescens (L.) R. Br. (Fabaceae), indigenous to the Western Cape region of South Africa, is found in a Mediterranean-type climate known for its many environmental stressors that can influence the levels of metabolites found in plants. Sutherlandia frutescens contains many known potential active constituents among them, flavonoids such as sutherlandins 3 and 4 (Su3 and Su4) and terpenoids such as sutherlandiosides B and D (SuB and SuD). Whether the profiles and levels of Su3, Su4, SuB and SuD are significantly affected by the environmental factors found in this area is however, unknown. iBatech™ is an ethanolic plant extract that is manufactured by researchers in the Department of Medical Biosciences, UWC, for use as a pesticide. HPLC analysis performed on Lycopersicon species treated with the iBatech™ product have shown that it also caused an increase in the concentrations of total polyphenols in the plant (Klaasen et.al., unpublished data). Whether the treatment with iBatech™ might also cause an increase in the polyphenols such as sutherlandins 3 and 4 and sutherlandiosides B and D is also unknown. The objectives of this study were to determine the concentrations of sutherlandins 3 and 4 (Su3 and Su4) and sutherlandiosides B and D (SuB and SuD) in S. frutescens collected from different sites and after the treatment with the iBatech™ product. The specific objectives were: a) to locate and categorize sites where S. frutescens is grown, based on a selection of pertinent environmental growth factors, b) to determine and compare the concentrations of sutherlandins 3 and 4 and sutherlandiosides B and D in S. frutescens collected from the different environmental growth sites and after treatment with the iBatech™ product. To realize these objectives, S. frutescens samples were collected from eight different sites and broadly categorized into three environmental categories. A high-performance liquid chromatography (HPLC) method using diode array ultraviolet detection (HPLC-DAD) for the simultaneous analysis of flavonoids and terpenoids was developed and validated, and used for the profiling and determination of the average levels of sutherlandins 3 and 4 and sutherlandiosides B and D in the samples from the sites and that treated with the iBatech™ product. The Kruskal-Wallis test was used to determine statistically significant differences among the environmental categories. The post ANOVA, Dunn's Multiple Comparison test was performed to determine which groups were significantly different. The Mann-Whitney, two-tail, t-test was used to compare each environmental category to the standard and the column statistics of the raw data was analyzed to determine significant differences among samples from the same environmental category. In the samples collected from the sites, the values represent the average levels of metabolites for each environmental category whereas the significance values indicated were among samples from the same environmental category. The levels for sutherlandin 3 were Afriplex™ (Std.) 2495.08, the natural field (NF) 2810.33 (P=0.0005), the cultivated field (CF) 2519.81 and the greenhouse (GH) 2580.25. The levels for sutherlandin 4 were significantly different when comparing the (NF) 1495.67 (P=0.0001), (CF) 3114.42 (P=0.0140) and (GH) 2361.72 (P=0.0001), with the CF group showing the highest levels of Su4 and the NF showing the lowest. The levels for sutherlandioside B were (NF) 189.7 (P=0.0189), (CF) 594.56 (P=0.0140) and (GH) 326.72 (P=0.0001), however, the CF group showed the highest average levels for SuB. The levels for sutherlandioside D were (NF) 144.1 (P=0.0192), (CF) 544.37 (P=0.0308) and (GH) 387.49 (P=0.0001), with the NF category having the lowest average levels. In the iBatech™ treated samples, the values indicate the average levels of three samples in each treatment group. The levels for sutherlandin 3 were (control) 9758.43, the (50%) 2232.63 and the (100%) 2031.97 treatment groups. The levels for sutherlandin 4) were (control) 2241.63, the (50%) 2247.47 and the (100%) 2392.60, with the 100% treatment group having the highest levels. The levels for sutherlandioside B were (control) 289.66, the (50%) 284.93 and the (100%) 332.30. The levels for sutherlandioside D were (control) 282.77, the (50%) 280.60 and the (100%) 315.13 treatment groups, with the 100% treatment group having the highest levels. The levels of Su3, Su4, SuB and SuD were significantly different (P=0.0001) among all treatment groups. In conclusion, the data shows that only sutherlandin 4 (Su4) was significantly different when comparing the environmental groups. Due to the significant differences in the Su3, Su4, SuB and SuD levels among samples from the same group the levels of these metabolites cannot be correlated with the environmental groups.Item Garlic and African olive used as traditional Herbs for hypertension in the Western Cape(University of the Western Cape, 2012) Blouws, Tarryn Alicia; Hughes, Gail D.; Puoane, ThandiHypertension is a common chronic health problem worldwide due to contributing factors such as obesity, physical inactivity, unhealthy diet and changes in lifestyle. The standard of care for hypertension in South Africa is prescription medication, as well as a stepwise programme; this treatment approach is for the treatment of hypertension according to severity using diuretics, beta-blockers, vasodilators in a stepwise progressive manner. In South Africa,traditional herbal medicines have been used to treat many ailments especially hypertension.Garlic and African olive has been reported as herbal medicines that have anti-hypertensive properties and may be used to control hypertension, either individually or in combination.The objective of this study is to 1) prevalence of these traditional herbal medicines will be investigated and 2) determine the prevalence of garlic and/ or African olive use among hypertensive patients lieu of/or in combination with prescription medication. The study design was cross-sectional, comprising of two phases. Phase one was the administration of questionnaires concerning the participants‘ demographics, medical/clinical history, chronic illness and traditional herbal treatment. One hundred and eighty participants from Prospective Urban Rural Epidemiological study (PURE) cohort were administered questionnaires. Of the 180 participants, 139 indicated that they are hypertensive, 30 hypertensive participants were selected to participate in the in-depth interviews. Phase two was divided into two parts which were detailed interviews including in-depth interviews and a focus group discussion. The focus group discussion was conducted with a convenience sample of 10 hypertensive patients who were available on the day of data collection. The questionnaire data was analysed with the Statistical Package for the Social Sciences (SPSS) and the interviews and focus group discussion was analysed using thematic content analysis.The results show that the participants with hypertension who are on prescription medication are also using traditional herbs, garlic and African olive as part of a dualistic health care treatment for their hypertension. The use of garlic is more prevalent than the use of African olive, as African olive was not well known among the participants.The results will facilitate in the acknowledgment of traditional herbal medicine use for hypertension, as either a home remedy for (other) chronic conditions or treatment in combination with prescription medication. It also highlights the necessity to educate participants and healthcare providers in the use of traditional herbal medicine. Furthermore, healthcare workers needs to be trained about THM and should also be obligated to ask about traditional herbal medicine among their patients.Item Nitrogen and carbon costs of growth and antioxidant production during acclimation to environmental stress in two species of gethyllis(University of the Western Cape, 2012) Daniëls, Christiaan Winston; Mabusela, Wilfred Thozamile; Valentine, Alexander J.; Marnewick, Jeanine L.Gethyllis multifolia L. Bolus and G. villosa Thunb. are winter-growing, summerblooming,deciduous and bulbous geophytes that grow naturally in the semi-arid succulent Karoo biome of South Africa. Both species grow under full sun conditions and have four distinctive growth phases: a winter (cold and wet) growing phase, leaf senescence phase towards spring, flowering phase during the hot and dry summer months, and fruit and leaf formation phase in autumn. The medicinal uses of this genus (including G. multifolia “Kukumakranka” and G.villosa “hairy kukumakranka”) range from cures for colic, digestive disturbances,teething problems, fatigue, boils, bruises and insect bites, to being used as an aphrodisiac. Gethyllis multifolia is threatened in its natural habitat and is listed in the ‘Vulnerable’ category of the ‘Red Data List of Southern African Plants’ and the ‘IUCN-World Conservation Union List of Plants’. The literature indicate that the habitats of both species are being exposed to drier conditions and is further threatened by the encroachment of invasive indigenous plant species. It is not known to which extent these factors may pose a threat to the existence of both species. The first objective of this investigation was to determine the costs of vegetative and reproductive growth during the seasonal life cycle of the plant, using carbon(C) and nitrogen (N) as a physiological currency. The second objective was to elucidate a functional basis to explain the difference in the conservation status of both species in their natural habitat. Both species were subjected to drought and shading as environmental stresses and the plant physiological performance was investigated via photosynthetic gas exchange. The third objective of the study was to evaluate the antioxidant content (total polyphenol, flavonol/flavone and flavanone content) and antioxidant capacity [ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and 2,2'-azino-di-3-ethylbenzthiazoline sulphonate (ABTS) radical cation scavenging ability] of natural populations and plant samples that were exposed to photo-and-drought environmental stresses. This study was done to elucidate the antioxidant profile of plant parts of natural populations as well as providing farmers, traditional healers and pharmaceutical companies with cultivation environmental conditions to enhance the antioxidant properties of the species. This investigation also attempted to isolate and characterize, by means of thin-layer chromatography (TLC) and column chromatography (CC), natural compounds from both species to lend support to the purported antioxidant benefit of both species and to further lend support to claims made by traditional healers of the medicinal potential of the genus. This study, however, did not engage in any in vivo studies or human trials to support published literature of the medicinal benefits of the genus.Item Nitrogen and carbon costs of growth and antioxidant production during acclimation to environmental stress in two species of Gethyllis(University of the Western Cape, 2012) Daniëls, Christiaan Winston; Mabusela, Wilfred T.Gethyllis multifolia L. Bolus and G. villosa Thunb. are winter-growing, summer blooming, deciduous and bulbous geophytes that grow naturally in the semi-arid succulent Karoo biome of South Africa. Both species grow under full sun conditions and have four distinctive growth phases: a winter (cold and wet) growing phase, leaf senescence phase towards spring, flowering phase during the hot and dry summer months, and fruit and leaf formation phase in autumn. The medicinal uses of this genus (including G. multifolia "Kukumakranka" and G. villosa "hairy kukumakranka") range from cures for colic, digestive disturbances, teething problems, fatigue, boils, bruises and insect bites, to being used as an aphrodisiac. Gethyllis multifolia is threatened in its natural habitat and is listed in the 'Vulnerable' category of the 'Red Data List of Southern African Plants' and the 'IUCN-World Conservation Union List of Plants'. The literature indicate that the habitats of both species are being exposed to drier conditions and is further threatened by the encroachment of invasive indigenous plant species. It is not known to which extent these factors may pose a threat to the existence of both species. The first objective of this investigation was to determine the costs of vegetative and reproductive growth during the seasonal life cycle of the plant, using carbon (C) and nitrogen (N) as a physiological currency. The second objective was to elucidate a functional basis to explain the difference in the conservation status of both species in their natural habitat. Both species were subjected to drought and shading as environmental stresses and the plant physiological performance was investigated via photosynthetic gas exchange. The third objective of the study was to evaluate the antioxidant content (total polyphenol, flavonol/flavone and flavanone content) and antioxidant capacity [ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and 2,2'-azino-di-3- ethylbenzthiazoline sulphonate (ABTS) radical cation scavenging ability] of natural populations and plant samples that were exposed to photo- and -drought environmental stresses. This study was done to elucidate the antioxidant profile of plant parts of natural populations as well as providing farmers, traditional healers and pharmaceutical companies with cultivation environmental conditions to enhance the antioxidant properties of the species. This investigation also attempted to isolate and characterize, by means of thin-layer chromatography (TLC) and column chromatography (CC), natural compounds from both species to lend support to the purported antioxidant benefit of both species and to further lend support to claims made by traditional healers of the medicinal potential of the genus. This study, however, did not engage in any in viva studies or human trials to support published literature of the medicinal benefits of the genus. The photosynthetic adaptation studies indicated that G. villosa had a better photosynthetic performance than G. multifolia during both drought and low light conditions because of the inability of G. multifolia to adapt to a wider range of environmental extremes. The C and N cost of growth and reproduction studies revealed that G. villosa had a more efficient resource utilisation strategy for both growth and reproduction. These physiological responses suggest that G. villosa, in general, has a more efficient survival strategy and that G. multifolia will struggle to adapt to drier environmental conditions, as well as growing in the shade of encroaching invasive plant species. To conclude, this could be a contributing factor as to why G. multifolia is threatened in its natural habitat and G. villosa not. The antioxidant content-and -capacity study on natural populations of both species revealed the highest total polyphenol content, FRAP and ORAC values for the flowers and fruits of G. multifolia and G. villosa compared to other plant parts. These values were found to be in line with and in some cases higher than most commercial fruits and vegetables. The antioxidant activity during drought and photo-stress of the leaves, bulbs and roots was found to be highest in the roots of both species during drought stress. Gethyllis multifolia, in general, exhibited higher total polyphenol content than G. villosa, with the highest content measured during drought stress in the roots of G. multifolia. Phytochemical investigation of the leaves, bulbs and roots of G. multifolia and G. villosa revealed the presence of tannins, flavonoids, phenolics, saponins, glycosides as well as essential oils, while alkaloids were absent. The chromatographic profiles of the leaves, bulbs and roots of both species further indicated that the roots of G. multifolia contained the highest concentration of natural products, compared to G. villosa and other plant parts. Further in-depth studies on the roots of G. multifolia led to the isolation and characterization of three known flavonoids, of which one was also isolated as its endogenously acetylated derivative. In contrast to the fact that both species had a high polyphenol content and exhibited high antioxidant activity, the isolated compounds in this study revealed very low antioxidant activity. However, the literature revealed that some of these isolated compounds exhibit antifungal, antibacterial, anti angiogenic and anti carcinogenic properties in vitro, which could be ascribed to the medicinal applications of plant parts of certain species belonging to this genus. Furthermore, this study suggests that further chemistry and pharmaceutical research on the genus, Gethyllis, in specific the flowers and fruit of these two species, be pursued.Item The impact of storage time and seasonal harvesting on biomarker levels of lessertia frutescens(University of Western Cape, 2012) Campbell, James; Mabusela, Wilfred Thozamile; Henkel, RalfIn South Africa, it is estimated that approximately 70% of the population frequently make use of traditional medicinal plants for their health care needs. The use of Lessertia frutescens by the various cultural groups in South Africa dates back to the earlier civilizations and continues to be used today to treat a multitude of ailments. To get the best results from a medicinal plant, one would need to ensure that the crude material is of good quality through interventions like being properly grown, well dried and correctly processed. This would add a measure of quality assurance, which will contribute towards the safety and efficacy aspect of herbal medicine. The aim of this study was to investigate what impact a particular season of harvest and the time in storage would have on the flavonoid and triterpenoid marker levels of Lessertia frutescens. To achieve this, the following was investigated: (1) storage variation of Lessertia frutescens leaves by comparing the results obtained from the High Performance Liquid Chromatography (HPLC) analysis of the flavonoids and triterpenoids, (2) seasonal variation of Lessertia frutescens leaves by comparing the results obtained from the HPLC analysis of the flavonoids and triterpenoids, (3) leaf and stem variation of Lessertia frutescens by comparing the results obtained from HPLC analysis of the flavonoids and triterpenoids. The hypotheses were: (1) the stored sample would indicate the same level of the biomarkers for the flavonoids and triterpenoids, as that of the freshly prepared sample, (2) the sample that was harvested during the summer season would indicate higher levels of the biomarkers of flavonoids and triterpenoids than the other three seasons, (3) the leaf sample would indicate the same level of the biomarkers for the flavonoids and triterpenoids, as that of the stem sample. An Agilent 1200 series HPLC was used for the determination of the flavonoids sutherlandin A and sutherlandin D as well as the triterpenoids sutherlandioside B and sutherlandioside D. Results show that for both sutherlandin A (summer: 3.67 ± 2.88 mg/ml; storage: 4.07 ± 2.88 mg/ml) and D (summer: 4.10 ± 1.06 mg/ml; storage: 4.25 ± 1.06 mg/ml) show significantly (P < 0.0001) higher concentrations in the case of the storage samples. For both sutherlandioside B (summer: 3.01 ± 0.39 mg/ml; storage: 2.82 ± 0.39 mg/ml) and D (summer: 5.82 ± 0.42 mg/ml; storage: 4.66 ± 0.42 mg/ml) show significantly (P < 0.0001) higher concentrations in the case of the fresh summer samples. For the seasonal comparison, results show that for sutherlandin A (summer: 3.67 ± 12.49 mg/ml; autumn: 4.75 ± 12.49 mg/ml; winter: 4.23 ± 12.49 mg/ml; spring: 6.56 ± 12.49 mg/ml) show significantly (P < 0.0001) higher concentrations in the case of the spring sample. For sutherlandin D (summer: 4.10 ± 10.32 mg/ml; autumn: 6.37 ± 10.32 mg/ml; winter: 5.25 ± 10.32 mg/ml; spring; 6.08 ± 10.32 mg/ml) show significantly (P < 0.0001) higher concentrations in the case of the autumn sample. For both sutherlandioside B (summer: 3.01 ± 7.19 mg/ml; autumn: 2.15 ± 7.19 mg/ml; winter: 2.89 ± 7.19 mg/ml; spring: 1.47 ± 7.19 mg/ml) and D (summer: 5.82 ± 14.48 mg/ml; autumn: 3.33 ± 14.48 mg/ml; winter: 4.23 ± 14.48 mg/ml; spring: 2.50 ± 14.48 mg/ml) show significantly (P < 0.0001) higher concentrations in the case of the autumn sample. For the summer leaf/stem comparison, results show that for sutherlandin A (leaf: 3.67 ± 8.18 mg/ml; stem: 4.67 ± 8.18 mg/ml) show significantly (P < 0.0001) higher concentrations in the case of the stem sample. For the sutherlandin D (leaf: 4.10 ± 4.81 mg/ml; stem: 3.31 ± 4.81 mg/ml) show significantly (P < 0.0001) higher concentrations in the case of the summer leaf sample. For both the sutherlandioside B (leaf: 3.01 ± 4.24 mg/ml; stem: 3.62 ± 4.24 mg/ml) and D (leaf: 5.82 ± 0.42 mg/ml; stem: 5.80 ± 0.42 mg/ml) show significantly (P < 0.0001) higher concentrations in the case of the stem samples.Results demonstrate that the production of secondary metabolites are influenced by environmental factors like seasonal harvesting, as indicated by the variation in the chemical constituent composition of Lessertia frutescens depending on the season collected in. Moreover, the storage of Lessertia frutescens for a period of one year resulted in an increase of two of the four constituents being monitored. There was slight variations in the chemical constituents, depending on whether the leaf or stem material of Lessertia frutescens was being used. Finally, the type of chemical constituent being monitored was also important in the consideration of this study. Therefore, this study can be seen as a starting point to further investigations of these aspects, which are of clinical, pharmacological and economic importance.Item The effects of maternal diets, varying in fat content, on proximal hepatic and skeletal muscle insulin signalling in neonatal wistar rat offspring(University of the Western Cape, 2013) Ndlovu, Zibele; Syce, James; Cerf, Marlon E.The incidence of type 2 diabetes (T2D) is persistently increasing globally. T2D is associated with pancreatic β cell dysfunction and insulin resistance in peripheral tissues such as the liver and skeletal muscle. Skeletal muscle is the major site for insulin stimulated glucose uptake. Maintenance on a gestational high fat diet may programme insulin resistance. Programming is induced by the exposure of organisms to either a stimulus or insult during foetal and/or early neonatal life and alters offspring physiology and metabolism. The aim of the present study was therefore to investigate the effects of maternal diets, varying in fat content, on neonatal hepatic and skeletal muscle gene (mRNA) and protein (immunoreactivity) expression of proximal insulin signalling factors: insulin receptor alpha (IRα), insulin receptor substrate 2 (IRS2) and phosphoinositide 3-kinase-p110 alpha (PI3K-p110α), and to assess the therapeutic potential of Aspalathus linearis extract after high fat programming. Pregnant rats were randomised into groups maintained on diets with varying fat proportions: 10% (control), 20% (20F), 30% (30F) and 40% (40F) fat as energy throughout gestation. Neonatal liver and skeletal muscle were collected to determine the proximal insulin signalling expression profiles of the target factors: IRα, IRS2 and PI3K-p110α. Quantitative polymerase chain reaction (qPCR) was applied to determine mRNA expression of these target insulin signalling factors. Immunostaining of the target proteins in the liver and skeletal muscle was performed followed by relative quantification with image analysis software. Further, Aspalathus linearis (Al) extract was orally administered to mothers during gestation in the 10% (Control-Al) and 40% (HFD-Al) diets at a dose of 150 mg/kg. Body weight, food intake and blood glucose concentrations were monitored throughout gestation in mothers. Maternal diets, varying in the percentage of fat content, showed no significant effect on neonatal hepatic IR and IRS2 mRNA expression. However, hepatic PI3K mRNA expression was elevated in 30F neonates compared to 20F neonates. Skeletal muscle IR and PI3K mRNA expression were reduced in the 30F and 40F neonates compared to 20F neonates. There was reduced hepatic IRα immunoreactivity in 40F neonates compared to control and 20F neonates. Further, skeletal muscle IRα immunoreactivity was significantly reduced in 30F and 40F neonates compared to control neonates. Therefore foetal high fat programming reduced IRα in both the liver and skeletal muscle which may impair proximal insulin signalling in these glucose recipient organs. Aspalathus linearis had no effect on maternal serum insulin and glucagon concentrations. In addition, maternal caloric intake, body weight and organ weights (liver, brain and pancreas) were not altered amongst the groups. Further, HFD-Al neonates were heavier than control neonates. In conclusion, Aspalathus linearis, at a dose of 150 mg/kg, had neither harmful nor ameliorative effects in pregnant mothers fed high fat diet during gestation. In addition, Aspalathus linearis treatment had no ameliorative effects on neonates from mothers fed high fat diet throughout gestation.Item Photosynthetic adaptation of two semi-arid species of Gethyllis (Kukumakranka) to drought-and-shade stress(Elsevier, 2013) Daniels, C.W.; Mabusela, Wilfred T.; Marnewick, Jeanine L.; Valentine, A.J.Gethyllis multifolia and Gethyllis villosa are winter-growing, summer-blooming, deciduous and bulbous geophytes that grow naturally in the semi-arid ‘Succulent Karoo Biome’ of South Africa. G. multifolia is threatened in its natural habitat and resides in the ‘Vulnerable’ category of the ‘Red Data List of Southern African Plants’. Previous investigations suggested that G. multifolia is more sensitive to drought stress than G. villosa and that both species adopted certain morphological changes in their leaves during shade stress. Current models indicate that this biome is being exposed to increasingly drier conditions and shading from encroaching indigenous plant species. In this study, the photosynthetic gas exchange responses of both species to drought and shade stresses were investigated and the ‘Vulnerable’ conservation status of G. multifolia. This investigation found that during drought stress G. villosa had a more enhanced photosynthetic performance than G. multifolia which appears not to be related to foliar adaptations such as specific leaf mass (SLM), but to the G. villosa's leaves maintaining their stomatal conductance (Gs), photosynthetic light compensation (LCP) and photon yields. Furthermore, during shade stress G. villosa also had an improved photosynthetic performance by not altering its photosynthetic LCP during reduced light conditions. It can be concluded that G. multifolia has a lower capacity than G. villosa to adapt its photosynthetic apparatus to changing environments such as increasing drought and shaded conditions. This may be a contributing factor to the threatened conservation status of G. multifolia.Item Sutherlandia frutescens: The meeting of science and traditional knowledge(Mary Ann Liebert, 2013) Aboyade, Oluwaseyi; Styger, Gustav; Gibson, Diana; Hughes, GailSutherlandia frutescens (L.) R.Br. (syn. Lessertia frutescens (L.) Goldblatt and J.C. Manning) is an indigenous medicinal plant extensively used in South Africa to treat a variety of health conditions. It is a fairly widespread, drought-resistant plant that grows in the Western, Eastern, and Northern Cape provinces and some areas of KwaZulu-Natal, varying in its chemical and genetic makeup across these geographic areas.1 Sutherlandia is widely used as a traditional medicine. Extensive scientific studies are being carried out on the safety, quality, and the efficacy of this medicinal plant to validate the traditional claims, elucidate the bioactive constituents, and conduct clinical trials. This has resulted in a unique situation in South Africa’s history, where traditional knowledge and science intersect to provide insight into this popular plant. This photoessay attempts to illustrate the interlinkage of science with the indigenous knowledge of traditional healers, the local knowledge of people who care for the sick, product development, and innovation agenda of the country as it relates to this plant.Item Antimicrobial activities of a novel biflavonoid and other constituents from Rhus natalensis(Academic Journals, 2013) Mwangi, Henry M.; Mabusela, Wilfred T.; Abegaz, Berhanu M.; Martin, Onani O.Phytochemical studies on Rhus natalensis root bark collected from Kenya led to the isolation and identification of a new biflavonoid (3-(1-(2,4-dihydroxyphenyl)-3,3-bis(4-hydroxyphenyl)-1-oxopropan-2- yl)-7-methoxy-4H-chromone-4-one (1), named rhuschromone, in addition to two other known compounds; 2',4'-dihydroxychalcone-(4-O-5''')-4'',2''',4'''-trihydroxychalcone (2) and 3-((Z)-heptadec-13- enyl) benzene-1,2-diol (3). The chemical structures of the isolated compounds were established using spectroscopic techniques including high field nuclear magnetic resonance (NMR). The total extracts and the isolated compounds were tested for their antimicrobial activities against different strains of bacteria.Item Evaluation of the antioxidant and anti-diabesity potential of cyclopia maculata using in vitro non-cell based screening models(University of the Western Cape, 2014) Matrose, Albertina Neliswa; Syce, James A.; Joubert, E; Malherbe, C.JThe aim of this study was therefore to evaluate the antioxidant and anti-diabesity potential of a hot water extract of C. maculata in non-cell based assays and correlate the activities with phenolic composition. Total antioxidant capacity (TAC) was assessed in terms of free radical scavenging and iron reducing ability. The DPPH, ABTS, ORAC and FRAP assays were employed. Anti-diabesity potential was assessed in terms of the inhibition of the digestive enzymes, α-glucosidase and pancreatic lipaseItem Some alkaloids and flavonoids from Cissampelos capensis(Academic Journals, 2015) Babajide, Jelili Olalekan; Mabusela, Wilfred T.; Green, IvanFollowing the screening of several plant species from an inventory of common medicinal plants from South Africa for medicinal properties, Cissampelos capensis was selected for further investigation due to its interesting and useful ethnomedicinal properties. This study attempts to relate specific constituents present in this plant with its widespread ethnomedicinal uses. Six compounds were isolated and their structures were unambiguously established by spectroscopic methods. The compounds are: 5,6-dehydro-4,5-dihydroxy-1,3,6-trimethoxy-17-methylmorphinan-7-one (1); 1,2-methylenedioxy-3-hydroxy -9,10-dimethoxyaporphine (2); 5,6-didehydro-4-hydroxy-3,6-dimethoxy-17-methylmorphinan-7-one (3); 3,7,8,3'-tetramethoxy- 6 - C-methyl- 5,4'-dihydroxyflavone (6 -C-methylquercetin 3, 3',7, 8 -tetramethyl ether) (4); 5, 7, 8 -trihydroxy-2?, 5?-dimethoxy-3?,4?- methylenedioxyisoflavanone (5); 3 -methoxy-6 -C-methyl-3',4',5,7,8 -pentahydroxyflavone (6 -C- methylquercetin -3-methyl ether) (6). Five of the isolated compounds, (viz., 1,2,4,5 and 6) have, to our knowledge, not been reported previously. The crude fractions and isolates were tested for cytotoxicity using the brine shrimp lethality test and for antimicrobial properties using nine microbes, including three Gram -ve, three Gram +ve bacteria and three fungi. The Gram-negative bacteria were Pseudomonas aeruginosa (NCTC 10332), Proteus vulgaris (NCTC 4175) and Escherichia coli Sero type 1 (NCTC 09001), while the Gram-positive bacteria were Bacillus subtilis (NCTC 8236), Staphylococcus aureus (NCTC 13134) and Bacillus licheniformis (NCTC 01097). The Fungal species used were Candida albicans (ATCC 90028), Candida eropiralis (ATCC 750) and Aspergillus niger (ATCC 10578). The n-Hex fractions were not active while the highest activities were found in the methanolic extracts. The total tertiary alkaloid fraction (TTA) showed the highest activity against the Bacillus substillis. Compounds 1, 2 and 5 appear to be the most promising with regards to the prospects of drug development.