In most countries, as many as 15 to 25% of the adult population have raised blood pressure. People with hypertension, and even those with mild elevation of blood pressure, are at an increased risk of cardiovascular disease, whether or not the symptoms are present. The risk of serious cardiovascular disease varies greatly among individuals and is also determined by a variety of concomitant risk factors other than the level of blood pressure. Hypertension develops as a result of disturbances of the body's blood pressure regulating system. The biological activity of the renin-angiotensin systems results from a series of specific enzymatic cleavages leading to the generation of angiotensin II, a potent vasoconstrictor. In the treatment of hypertension, inhibition of the angiotensin converting enzyme is established as one modern therapeutic principle. Angiotensin converting enzyme inhibitors act by inhibiting the conversion of angiotensin I to angiotensin II. The in vitro assay, developed by ELBL and WAGNER (1991) for the detection of angiotensin converting enzyme inhibitors in plant extracts was successfully established during this study. Plants used by traditional healers in South Africa for the treatment of high blood pressure were investigated for their antihypertensive properties, utilizing the established angiotensin converting enzyme assay. Twenty plants were investigated for their angiotensin converting enzyme inhibitory activity. The highest inhibition (97%) was obtained by Adenopodia spicata leaves. A further seven plants exhibited an inhibition greater than 70% and five more over 50%. Plants exhibiting inhibition levels greater than 50% were further tested for the presence of tannins in order to eliminate possible false positives. The leaves of Tulbaghia violacea were chosen for bioassay-guided fractionation in an attempt to isolate the active compound(s). Serial extractions were made of ground Tulbaghia violacea leaves using polar to non-polar solvents to establish the solvent giving optimum extraction of the active compound(s). Distilled H2O was selected as the extractant and a bulk extract was performed on 0.7 kg ground leaves. The extracted residue was partitioned against butanol, fractionated using cation exchange resin chromatography, Sephadex ® LH-20 and high performance liquid chromatography. Fractions collected after each purification step were assayed using the angiotensin converting enzyme assay. Fractions exhibiting high levels of angiotensin converting enzyme inhibition were selected for further purification. The active fraction from the final high performance liquid chromatography step used in this study requires further attention in order to purify and identify the active compound(s). The chromatographic and chemical properties of the compound(s) present in the isolated active fraction are discussed. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.

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The HIV-1 pandemic affects millions of people worldwide with approximately 70% of those affected residing in sub-Saharan Africa (SSA) relying on traditional medicines for treatment. The key aim of the study was to isolate and characterise an active phyto-pharmaceutical ingredient (API) from L. trigonus for use as a vaginal microbicide. The aerial parts of L. trigonus were oven-dried at 80°C, ground and then extracted with boiling water for 30 minutes. Aqueous extracts were screened using an HIV-1 neutralization assay in TZM bl cells. Chromatographic and spectroscopic techniques were used to purify, isolate and identify the API. The API (BP36-117-26464C) was identified as a polymeric macromolecule with IC50 = 0.04 μg/ml against HIV-1 HXB 2 subtype B. This activity is comparable to the ARV drug, enfuvirtide (IC50 = 0.02 μg/ml). The API consists of galacturonic acid polymer and a mixture of seven compounds. Its mode of action may involve inhibiting virus attachment. The activity of this precipitate (BP36-117-26464C) tested against HIV-1 subtype C pseudovirions and shown to compare favorably with that of enfuvirtide (T20). The water-soluble nature of this API and its mode of action identified it as a potential microbicide. In the current form, the precipitate (API) would be difficult to develop as an oral treatment for HIV, as high-molecular weight agents often have poor bioavailability following oral administration. However, large molecules with potent anti-HIV activity are ideal for topical use and potent development as a microbicide. / Life & Consumer Sciences / M.Sc (Life Sciences)

The HIV-1 pandemic affects millions of people worldwide with approximately 70% of those affected residing in sub-Saharan Africa (SSA) relying on traditional medicines for treatment. The key aim of the study was to isolate and characterise an active phyto-pharmaceutical ingredient (API) from L. trigonus for use as a vaginal microbicide. The aerial parts of L. trigonus were oven-dried at 80°C, ground and then extracted with boiling water for 30 minutes. Aqueous extracts were screened using an HIV-1 neutralization assay in TZM bl cells. Chromatographic and spectroscopic techniques were used to purify, isolate and identify the API. The API (BP36-117-26464C) was identified as a polymeric macromolecule with IC50 = 0.04 μg/ml against HIV-1 HXB 2 subtype B. This activity is comparable to the ARV drug, enfuvirtide (IC50 = 0.02 μg/ml). The API consists of galacturonic acid polymer and a mixture of seven compounds. Its mode of action may involve inhibiting virus attachment. The activity of this precipitate (BP36-117-26464C) tested against HIV-1 subtype C pseudovirions and shown to compare favorably with that of enfuvirtide (T20). The water-soluble nature of this API and its mode of action identified it as a potential microbicide. In the current form, the precipitate (API) would be difficult to develop as an oral treatment for HIV, as high-molecular weight agents often have poor bioavailability following oral administration. However, large molecules with potent anti-HIV activity are ideal for topical use and potent development as a microbicide. / Life and Consumer Sciences / M.Sc (Life Sciences)

Cowpea (Vigna unguiculata) and moringa (Moringa oleifera) are nutritious and medicinal vegetables, but could also harbor harmful microbial contaminants. The main aim of the project was to determine the effect of each processing techniques on the microbiology, proximate nutrients and shelf life of these vegetables to produce nutritious, tasty, safe and long lasting vegetable products. The processing techniques used were: washing, blanching, and drying. Leaf samples were collected at each stage of processing and were analysed for total viable count, coliform count, yeast and mould count and nutritional content. Microbial plate analysis showed the presence, particularly on cowpea leaves, of yeasts and bacteria such as Pseudomonas, Klebsiella, Staphylococci, Streptococci, and enterobacter including enteropathogens such as Salmonella spp., Shigella dysenteriae and E coli. The presence of E.coli on the leaves was also confirmed using polymerase chain reaction-amplified ribosomal DNA analysis. The most effective processing technique which reduced microbial load to below SABS standards while retaining nutritional quality was the washing of the leaves twice with tap water followed by steam tunnel blanching at 94oC for 12 minutes. Oven drying the leaves at 60oC gave satisfactory and extended shelf life results. Proximate analysis comparison of the two leaf types showed that on average moringa leaves contained more ash (2.37 vs 1.1 g), protein (6,9 vs 3,6 g), fat (0,41 vs 0.2 g) and energy (305,1 vs 70KJ) but less dietary fibre (0,9 vs 7,5 g) than cowpea leaves. No significant differences were noted in these values following washing and steam blanching. These results indicate that washing of these leaves is effective as to reducing microbial load and maintaining proximate values in the short term (up to 4 days) but that oven drying is effective for longer-term storage. / Life and Consumer Sciences / M. Sc. (Life Sciences)

Cowpea (Vigna unguiculata) and moringa (Moringa oleifera) are nutritious and medicinal vegetables, but could also harbor harmful microbial contaminants. The main aim of the project was to determine the effect of each processing techniques on the microbiology, proximate nutrients and shelf life of these vegetables to produce nutritious, tasty, safe and long lasting vegetable products. The processing techniques used were: washing, blanching, and drying. Leaf samples were collected at each stage of processing and were analysed for total viable count, coliform count, yeast and mould count and nutritional content. Microbial plate analysis showed the presence, particularly on cowpea leaves, of yeasts and bacteria such as Pseudomonas, Klebsiella, Staphylococci, Streptococci, and enterobacter including enteropathogens such as Salmonella spp., Shigella dysenteriae and E coli. The presence of E.coli on the leaves was also confirmed using polymerase chain reaction-amplified ribosomal DNA analysis. The most effective processing technique which reduced microbial load to below SABS standards while retaining nutritional quality was the washing of the leaves twice with tap water followed by steam tunnel blanching at 94oC for 12 minutes. Oven drying the leaves at 60oC gave satisfactory and extended shelf life results. Proximate analysis comparison of the two leaf types showed that on average moringa leaves contained more ash (2.37 vs 1.1 g), protein (6,9 vs 3,6 g), fat (0,41 vs 0.2 g) and energy (305,1 vs 70KJ) but less dietary fibre (0,9 vs 7,5 g) than cowpea leaves. No significant differences were noted in these values following washing and steam blanching. These results indicate that washing of these leaves is effective as to reducing microbial load and maintaining proximate values in the short term (up to 4 days) but that oven drying is effective for longer-term storage. / Life and Consumer Sciences / M. Sc. (Life Sciences)