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DOI: 10.1055/s-0029-1234559
Antimicrobial activity of pentacyclic triterpenes isolated from Berkheya bergiana
The use of medicinal plants in the world and especially in South Africa, contributes significantly to Primary Health Care1. The genus Berkheya belongs to the family Astereceae2. B. bergiana leaves and stem are used as traditional medicine. Decoction of leaves and roots are used for the treatment of coughs, gonorrhoea, rheumatism and abdominal disorders especially for pains after eating. It is also used as anti-emetics3. Unusual sesquiterpenoids and thiophene derivatives have been isolated from Berkheya species3. The aim of the study was to provide scientific rationale for the use of the plant in traditional medicine through bioassay-guided fractionation of B. bergiana leaves. Bioactivity testing was done against selected microbes using disc diffusion technique as outlined in Clinical Laboratory Standard Institute (CLSI). Structure elucidation of the isolated compounds was based primarily on 1D and 2D NMR analyses, including HMQC, HMBC and NOESY correlations. Fractionation yielded some triterpenoids; 20(29)-Lupene-1,3-diol, 3-Methoxy-20(29)-lupene and 17-Epilupenyl acetate. The compounds were active against 25 bacterial strains both standard and isolates and were active against P. aeruginosa ATCC 7700, P. vulgaris ATCC 6830, S. marscens ATCC 9986, E. coil ATCC 8739 S. epididirmis, Salmonella spp, E. faecalis etc. These results explain the support the use of B. Bergiana leaves for the treatment of infectious diseases in traditional South Africa medicine. It also shows that the antimicrobial activity is concentrated in the triterpenoid fractions.
Acknowledgements: The authors are grateful to the NRF, South Africa and University of Zululand Research Committees for financial support
References: [1] Van der Watt, E., Pretorius, J.C. (2001)J. Ethnopharmacol. 76:87–91.
[2] Van Wyk, B.K., Gericke, N. (2000) People's Plants. Briza Publications, Pretoria, South Africa.
[3] Hutchings, A. et al. (1996) Pietermaritzburg, University of Natal Press.