<p>We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade / , Rovral&trade / , Terminator&trade / and Teldor&trade / at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade / significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. 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.</p>

The extraction yields of insoluble dietary fibre (IDF) and soluble dietary fibre (SDF) from seven whole-grain cereals (WG) ranged from 11.73% to 23.71% and 2.28% to 5.15%, respectively. Eight monomeric phenolic acids and four diferulic acids were identified and quantified in cereal alkaline extracts by reversed phase high performance liquid chromatography coupled with quadrupole - time of flight mass spectrometry. IDF alkaline extracts had significantly (p < 0.05) higher levels of total phenolic content (TPC) and DPPH radical scavenging activity than WG and SDF extracts. Corn IDF (C-IDF) extracts exhibited the highest TPC and DPPH, followed by red rice. MTT cell viability assay indicated that 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) or xanthine-xanthine oxidase (X-XO) induced cell loss can be effectively reduced by pre-incubating Caco-2BBe or FHs 74 Int cells with certain levels of C-IDF extracts. This effect was speculated to be associated with the antioxidant activity of C-IDF linked phenolic compounds.

Thesis (Ph.D. (Dietetics))--North-West University, Potchefstroom Campus, 2010.

The extraction yields of insoluble dietary fibre (IDF) and soluble dietary fibre (SDF) from seven whole-grain cereals (WG) ranged from 11.73% to 23.71% and 2.28% to 5.15%, respectively. Eight monomeric phenolic acids and four diferulic acids were identified and quantified in cereal alkaline extracts by reversed phase high performance liquid chromatography coupled with quadrupole - time of flight mass spectrometry. IDF alkaline extracts had significantly (p < 0.05) higher levels of total phenolic content (TPC) and DPPH radical scavenging activity than WG and SDF extracts. Corn IDF (C-IDF) extracts exhibited the highest TPC and DPPH, followed by red rice. MTT cell viability assay indicated that 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) or xanthine-xanthine oxidase (X-XO) induced cell loss can be effectively reduced by pre-incubating Caco-2BBe or FHs 74 Int cells with certain levels of C-IDF extracts. This effect was speculated to be associated with the antioxidant activity of C-IDF linked phenolic compounds.

Thesis (Ph.D. (Dietetics))--North-West University, Potchefstroom Campus, 2010.

Carbonyl and oxidative stress augment the development of diabetic complications. We evaluated the cytoprotectiveness of walnut and hazelnut extracts and catechins for decreasing cytotoxicity, lipid peroxidation, reactive oxygen species (ROS) formation, and protein carbonylation in cell death models of carbonyl and oxidative stress. Polar extracts (methanol or water) showed better cytoprotection than the non-polar (ethyl acetate) nut extracts against hydroperoxide-induced hepatocyte cell death and oxidative stress markers. Catechin flavonoids found in plants, including walnuts and hazelnuts, prevented serum albumin carbonylation in a carbonyl stress model (using glyoxal or methylglyoxal). Hepatocyte protein carbonylation and cell death were prevented and UV spectra data suggested a catechin:methylglyoxal adduct was formed. We conclude that (a) bioactive nut constituents in polar extracts were more protective than non-polar extracts against oxidative stress, and (b) catechins were effective under physiological temperature and pH, at preventing dicarbonyl induced cytotoxicity likely by trapping dicarbonyls or reversing early stage carbonylation.

Carbonyl and oxidative stress augment the development of diabetic complications. We evaluated the cytoprotectiveness of walnut and hazelnut extracts and catechins for decreasing cytotoxicity, lipid peroxidation, reactive oxygen species (ROS) formation, and protein carbonylation in cell death models of carbonyl and oxidative stress. Polar extracts (methanol or water) showed better cytoprotection than the non-polar (ethyl acetate) nut extracts against hydroperoxide-induced hepatocyte cell death and oxidative stress markers. Catechin flavonoids found in plants, including walnuts and hazelnuts, prevented serum albumin carbonylation in a carbonyl stress model (using glyoxal or methylglyoxal). Hepatocyte protein carbonylation and cell death were prevented and UV spectra data suggested a catechin:methylglyoxal adduct was formed. We conclude that (a) bioactive nut constituents in polar extracts were more protective than non-polar extracts against oxidative stress, and (b) catechins were effective under physiological temperature and pH, at preventing dicarbonyl induced cytotoxicity likely by trapping dicarbonyls or reversing early stage carbonylation.

Aldose reductase, E.C.1.1.1.21, catalyzes the reduction of different types of aldehydes to their corresponding alcohols, and especially reduces various aldo-sugars using NADPH as the coenzyme. Under hyperglycemic conditions aldose reductase is involved in the development of diabetic complications. As a result, interest has been placed over the years on the development of potent aldose reductase inhibitors for possible use in the therapy of these severe diabetic complications. In this study, aldose reductase was isolated from bovine lens by differential centrifugation and ammonium sulfate precipitation. The conditions for the enzyme assay / such as substrate (DL-Glyceraldehyde) and coenzyme (NADPH) concentration, protein amount, effect of sulfate ions, temperature and pH on the enzyme activity were optimized. The inhibitory effects of Punica granatum, Spinacia olaeracea, Allium cepa Allium porrum, Malus flouribunda, Malus domestica extracts were tested on crude bovine lens aldose reductase. Four different types of organic fractions from each crude plant extract were obtained by solvent fractionation. The inhibitory activity of these organic fractions was calculated considering the aldose reductase activity without extracts as 100 %. All six plants were found to inhibit aldose reductase activity to different extent. Among these fractions obtained as / petroleum ether, diethyl ether, ethyl acetate, and n-butanol. Highest inhibitory activity was found for the ethyl acetate fraction. The IC50 values of ethyl acetate fractions of all these plants was calculated as, 25.46 &micro / g/ml, 20.5 &micro / g/ml, 18.5 &micro / g/ml, 12.32 &micro / g/ml, 6.45 &micro / g/ml, 5.4 &micro / g/ml, for Allium porrum, Malus domestica, Spinacia olaeracea, Malus floribunda Allium cepa, Punica granatum respectively.

<p>In 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.</p>

<p>Early man dabbled with the use of plant extracts to cure ailments. This practice has been passed down from generation to generation and today more than 50% of the world'sdrugs are natural products or derivatives thereof. Scientists have thus established a branch of research called natural product research. This branch of research involves the identification and purification of secondary metabolites with a specific biological activity. The methodology involves the screening of plant products for a specific biological activity, purification of the biologically active natural product by separation technology and structure determination. The biologically active natural products is then further scrutinized to serve as a novel drug or lead compound for the development of a novel drug. This research exploited this research methodology.</p>