In Ethiopia, many plants are used for medicinal purpose by traditional healers without any scientific justification for their therapeutic values. The principal Aim of this study were to evaluate the in vitro antibacterial and antifungal activities of the leaf, root and stem bark extracts of Rhamnus prinioides (gesho), Justicia schimperiana (sensel) and Ruta chalepensis (Tena adam) against some common pathogenic species of bacteria and fungi. The results of this study revealed that the crude extracts of ethanol, methanol, hexane and water extracts had antimicrobial activities on most bacterial and fungi species of some solvent extracts. Methanol and ethanol extracts had the highest growth inhibitory effects as compared with those of the aqueous and hexane crude extracts. However, the four solvent crude extracts had less antimicrobial activities than chloramphenicol and clotrimazole. Campylobacter jejuni and Staphylococcus aureus were found to be the most susceptible pathogen to the crude ethanol (99.5%). The growth inhibitory activities of the crude extracts were found to be significantly different for both concentrations (30 and 60 mg/ml) in all plant parts (p < 0.05). In conclusion, this study did not only show the antibacterial activities of R. prinioides (gesho), J. schimperiana (sensel) and R. chalepensis (Tena adam) but also offered a scientific validation for its traditional use against some diseases.

Keywords: antimicrobial activities, phytochemical screening, MIC