In vitro antimicrobial activity of six Ethiopian medicinal plants against Staphylococcus aureus, Escherichia coli and Candida albicans

Introduction: Traditional herbal medicines are attracting significant attention in global health debates with various traditional herbal remedies being used as the basis for modern medicines. The aim of this research was to explore the potential antimicrobial activity of six medicinal plants. Methods: In vitro antimicrobial activity of essential oils extracted from Lavandula angustifolia , Cymbopogon citratus , Mentha piperita as well as extracts from Chenopodium ambrosioides , Aloe ankoberensis and Aloe pulcherima were determined using an agar diffusion technique. The minimum inhibition zone concentration (MIZC) was determined by a twofold serial dilution using a modified agar dilution method. Results: Results demonstrated that 50 mu L of the essential oils from three plants had antimicrobial activity. The MIZC of essential oil from L. angustifolia for the growth of Staphylococcus aureus , Escherichia coli and Candida albicans ranges from 12.5 % (v/v) to 25 % (v/v). Whereas, the MIZC of essential oils from C. citratus and M. piperita for the growth of these pathogens ranged from 6.25 % (v/v) to 12.5 % (v/v). The MIZC of ethanol extract of C. ambrosioides , A. ankoberensis and A. pulcherima for both S. aureus and E. coli were 250 mg/mL and 125 mg/mL, respectively. However, petroleum ether and chloroform extracts (1000 mg/mL) of C. ambrosioides , A. ankoberensis and A. pulcherima failed to inhibit these organisms. Conclusion: These findings suggest that the herbal essential oils and extracts had activity against S. aureus , E. coli , and C. albicans . Ethanol extracts appear to have a better antimicrobial activity than petroleum ether and chloroform extracts.