<i>In vitro</i> evaluation of the antimicrobial activities of selected medicinal plants

Abstract

The 80% methanol extracts of the dried, ground plant materials of Inula confertiflora, Clematis simensis, Zehneria scabra and Pycnostachys abyssinica were tested for antimicrobial activity against common bacterial and fungal pathogens by the agar well diffusion method. The minimum inhibitory concentration (MIC) determination and evaluation of topical antimicrobial formulations were also carried out on the 80% methanol extract of I. confertiflora. The results indicated that all of the plant extracts exhibited antimicrobial activities against one of the most common bacterial pathogens, namely Staphylococcus aureus. In addition, a good antifungal activity against Trichophyton mentagrophytes was exhibited by the extract of I. confertiflora, which lends some credibility to the traditional uses of the plants. Evaluation of topical formulations of the 80% methanol extract of I. confertiflora demonstrated that the hydrophilic formulations exhibit higher antimicrobial activities (as compared to their hydrophobic counterparts) that were comparable (in case of their activity against T. mentagrophytes) to the commercially available antifungal products.

Keywords: medicinal plants, antimicrobial activities, agar well diffusion method, minimum inhibitory concentration, topical formulations

Ethiopian Pharmaceutical Journal, vol. 22 (2004): 1-14