Antibacterial and antifungal activities of extracts of Zanthoxylum chalybeum and Warburgia ugandensis, Ugandan medicinal plants.

Olila, D., Olwa-Odyek, and Opuda-Asibo,J
Departments of Veterinary Physiological Sciences, Makerere University , P .O. Box 7062, Kampala, Uganda.
Department of Pharmacy Makerere University , P .O. Box 7072, Kampala, Uganda.
Veterinary Public Health and Preventive Medicine, Makerere University , P .O. Box 7062, Kampala, Uganda.

ABSTRACT
Measles is a killer disease of children in Uganda. The treatment of the disease is mainly directed at the secondary microbial infections. A large proportion of the population in Uganda still relies on the use of herbal remedies, which have been claimed to produce beneficial responses. In this study , the efficacy of Warburgia ugandensisand Zanthoxylum chalybeumagainst common bacteria and fungi was investigated. Bactericidal and antifungal assays were done using extracts derived fromZ. chalybeumandW. ugandensis(agar well diffusion, disc diffusion and colony count assays).

All extracts (ethanolic, petroleum ether and aqueous) of Z. chalybeumdid not show antimicrobial activity . Phytochemical investigations of Zanthoxylum chalybeum(seed) yielded a pure crystalline alkaloid (27-135D) which was characterized as skimianine based on  H-NMR spectroscopy and comparison with spectra of authentic samples. Skimmianine did not have antimicrobial activity in this test system. W. ugandensiswater extracts elicited antibacterial activity against both Escherischia coliand Staphylococcus aureus in the agar well assay but not in the disc diffusion assay.

Warburgia ugandensiswater extracts and fraction 27-163D also showed antifungal activity against Candida albicans. Chromatography of extracts of Warburgia ugandensisstem bark afforded compound 49-169K, which was characterized as the sesquiterpine muzigadial (by  1 H-NMR spectroscopy), which did not show antibacterial activity but had antifungal activity against C. albicans.

Therefore, the claimed efficacy of W. ugandensiscould be attributable to antibacterial and antifungal activity of its components. Since Z. chalybeumextracts had neither antifungal nor antibacterial activities, its mode of action is unclear from these results. African Health Sciences 2001; 1(2): 66-72