Ethnopharmacology and phytochemistry of some selected medicinal plants in KwaZulu Natal.

Thesis (M.Sc.)-University of KwaZulu-Natal, 2006.In this ethnopharmacological study to isolate, purify, identify and test crude and isolated compounds from organic and aqueous extracts from stem and leaves of Protorhus longifolia and Sclerocarya birrea, stem bark of Hibiscus cannabinus and Heteropyxis natalensis, leaves of Acokanthera venenata, Carissa marcrocarpa and Syzygium cordatum, seeds of Chiononthus foveolatus and calyces of Hibiscus sabdariffa were tested against seven pathogenic microorganisms which included six bacterial species [Klebsiella pneumoniae (ATCC 12265), Bacillus cereus (ATCC 11778), Salmonella typhimurium (ATCC 13311), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 35219), Staphylococcus aureus (ATCC 29213)) and fungal yeast Candida albicans (ATCC 10231)]. Both organic and aqueous extracts from these medicinal plants exhibited antimicrobial properties against one or more mlcroorgamsms. The extracts of stem bark and leaves were tested for antimicrobial properties. Crude extracts that showed the highest activity were analysed through chromatographic and spectroscopic techniques to isolate, purify and characterise their active components. The highly active antimicrobial extracts were further tested for antimicrobial activity. Chromatographic (TLC and CC) spectroscopic (IR, 13C, 1HNMR) analyses of Syzygium cordatum leaf extract in ethyl acetate revealed the presence of C-30 triterpenes, ursolic (3B-hydroxyurs-12-en-28-oic acid) (UA) and oleanolic (3-hydroxylean-12-en-28-oic acid) (OA) acids; a mixture of methyl maslinate (2a, 3B-dihydroxyolean-12-en-28-oic acid methyl ester) (MM) and methyl corosolate (MC). Analyses of Protorhus longifolia leaf extract in hexane and ethylacetate revealed the presence of the alkaloid lupeol (lup-20(29)-en-3pB-ol), lupenone [lup - 20 (29) - en - 3 - one or lup - 20 ( 30 ) - en - 3 - one], lupinine (octahydro-2H-quinolizine-lmethanol), lupulon (3 ,5-dihydroxy-2,6,6-tris(3-methyl-2-butenyl)-4-(3-methy1-1-oxobutyl)-2,4-yclohexadien-1-one) or (3,5-dihdroxy-4-isovaleryl-2,6,6-tris(3-methyl-2-butenyl)-2, 4-cyclohexadien-1-one) and luteolin [(2-(3, 4-dihydroxyphenyl)-5, 7-dihydroxy-4H -1-benzopyran-4-one), 3',4', 5,7 -tetrahydroxyflavone or 5,7,3' 4' - tetrahydroxyflavone] and other compounds to be characterised in future studies. Sclerocarya birrea bark extract in methanol was found to contain mixtures of compounds that could not be separated due to solvent complications. Heteropyxis natalensis stem bark in ethyl acetate gave betunilic acid (3B-hydroxy-20(29)-lupaene- 28-oic acid) as a major compound