Antimicrobial properties of some medicinal plants of the Luo community of Kenya

Background: The Luo community of Kenya rely mostly on ethno-medicine to manage human ailments. This study was set to survey, record and report the medicinal plant species they use to manage infectious conditions. Objective of this study was to screen the plants used by this community to treat microbial infections, to demonstrate their in-vitro antibacterial and antifungal activities. Methodology: Eight plants namely Lannea stuhlmanii, Carissa edulis, Combretum fragrans, Conyza sumatrensis, Ormocarpum trichocarpum, Sida cuneifolia, Plumbago zeylanica, and Rhoicissus revoilii, used by the Luo for treatment of microbial infections, were studied. Observations and semi-structured interviews were used to gather ethno-botanical data for each plant. About 3 kg of suitable specimens were harvested, with leaves pressed and preserved for identification at University of Nairobi’s Department of Botany Herbarium. Voucher specimens were also deposited at the University’s School of Pharmacy Herbarium and excess material powdered and kept dry. The pressed specimens were dried at 20 0C to 25 0C using plant blower. Their ethanolic extracts were screened for their antimicrobial activity against Candida albicans, Escherichia coli, Staphylococcus aureus and Bacillus pumulus. Results: Extracts from Conyza sumatrensis, C. fragrans, C. edulis, S. cuneifolia, R. revoilii and leaf C. sumatrensis had good activity against E. coli. Activity against B. pumulus was observed in all extracts except those of L. stuhlmanii bark and R. revoilii tubers. Good activity against S. aureus was observed with C. fragrans, S. cuneifolia and L. stuhlmanii. Rhoicissus revoilii, L. stuhlmanii, C. fragrans and C. edulis exhibited good antifungal activity against Candida albicans. Conclusion: This work partially supports the traditional antimicrobial use of the various plants, and it is hoped that the results will form the basis for further research that could lead to isolation and/or development of antibacterial and antifungal medicines for use in primary health care. The results also confirm that plants are a potential source of antimicrobial compounds