IN VITRO ANTIMICROBIAL ACTIVITY OF SELECTED MEDICINAL PLANTS IN LOSHO, NAROK COUNTY KENYA

Abstract

In Kenya, microbial infections are a major cause of morbidity. Antibiotic effectiveness is threatened by increasing resistance of pathogenic microbes against most available drugs as new pathogens continue to emerge. Currently, herbal remedies offer hope considering they are readily and cheaply available. Antimicrobial activity of crude extracts of four selected plants namely Schrebera alata (Hochst.)Welw. (Oleaceae), Ormocarpum kirkii (Taub.) Engl. (Papilionoideae), Helichrysum forskahlii (J.F. Gmel.) Hilliard & B.L. Burttv (Asteraceae) and Cussonia holstii Harms ex Engl. (Araliaceae) that are medicinally used by herbalists from Losho, Narok County Kenya for treatment of ear, nose and throat infections (ENT), gastrointestinal disorders and skin ailments was done. Qualitative antimicrobial susceptibility test against five microorganisms, methicillin resistant Staphylococcus aureus (MRSA), Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans was investigated using Agar diffusion methods to generate inhibition zones and data accrued analyzed using Analysis of variance (ANOVA). Minimum inhibitory concentrations (MICs) were determined by broth micro dilution method. It was observed that the organic crude extracts of H. forskahlii had the highest inhibition zone diameters against MRSA of 19.5 and 18.5 mm in agar well and agar disk diffusion respectively. Moreover, organic extracts of H. forskahlii revealed the highest antifungal inhibition zone value equal to 8.5 mm in agar well diffusion. MIC values varied with plant samples from 15.625 to 250 mg/ml. The study has shown that H. forskahlii and O.kirkii possess promising antimicrobial activity against microbes of health importance and could lead to the isolation of new and effective antimicrobial compounds.