Antimicrobial activities of selected medicinal plants of the Tugens of Koibatek, district, Kenya.

Abstract

Based on the number of ailments a plant is used to treat and the difficulty in propagating them from seeds, nine top ranked species were selected for this study. Plant barks were extracted, air dried, ground to moderately fine powder and soxhlet extracted with methanol. The extracts were screened for alkaloids, sterols, saponins, flavanoids and anthraquinones. Antimicrobial tests were performed with five bacteria and one fungus strains using agar diffusion method. Brine Shrimp Lethality test was also used to test for bioactivity. Probit analysis on a Finney computer program was used to determine the lethal concentration (LC50) for half of the test organisms. Ethnobotanical survey results indicated that the local people used 47 medicinal tree species and their uses were identified. Two to four secondary compounds were recorded in extracts of all species. Extracts exhibited antibacterial activity against one to four types of bacteria with inhibition zones ranging from 18 – 34 mm. Extracts from all species except Myrica salicifolia, Toddalia asiatica and Rauvolfia caffra showed antifungal activity.