Dried leaves of Abrus precatorius, Desmodium ramosissimum, Scoparia dulcis and aerial parts of Phyllanthus amarus used in folkloric medicine of Ebiraland were extracted with hexane, methanol and water sequentially using soxhlet apparatus. The extracts were screened for antimicrobial activities against Bacillus subtilis, E. coli, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus and Candida albicans using the agar-cup diffusion protocol. All the extracts except the hexane extract of Abrus precatorius were active against at least two of the test microorganisms at the highest concentration of 100 mg/ml used in this study. The aqueous and methanolic extracts of Phyllanthus amarus were active against all the test microorganisms. The methanolic extract of Phyllanthus amarus also showed a broad spectrum of activity with a minimum inhibitory concentration (M.I.C.) of 1.56 mg/ml against all the test microorganisms. The extracts were also screened for secondary metabolites and the result indicated the presence of alkaloids, saponins, tannins and terpenoids. The results of this investigation, appears to justify the ethnomedicinal uses of these plants for the traditional treatment of infectious diseases. However, further investigation is required to obtain more information on their antimicrobial potentials and also to isolate their bioactive compounds.
Keywords: Medicinal plants, antimicrobial activity, minimum inhibitory concentration, phytochemical screening.