Evaluation of the antimicrobial activities of the crude methanol and aqueous extracts of <i>Millettia aboensis</i> on selected strains of organism

Abstract

This study was conducted to evaluate the antimicrobial activities of aqueous and methanol root extracts of M aboensis. The roots of M aboensis were cut into small pieces, air dried and milled. The resulting powder was subjected to extraction by cold maceration using methanol and water. The antimicrobial activities of the extracts were evaluated against five bacterial species (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi, Klebsiella pneumonia) and Candida albicans using agar well diffusion method. The minimal inhibitory concentration (MIC) of crude methanol extract of Millettia aboensis was determined using agar diffusion method. The phytochemical analysis was to determine the secondary metabolites and the analysis shows the presence of saponins, reducing sugars etc. Antimicrobial susceptibility tests show that the aqueous extract exhibited more effect against both bacteria and the fungus than the methanol extract. The inhibition zone diameter (IZD) of the aqueous extract at different concentrations showed activity against all the bacteria species at 333.33 mg/ml and 166.67 mg/ml, while at 83.34 mg/ml concentration, only Klebsiella pneumoniae was inhibited. Their IZDs were in the range of 18-21mm. The MICs ranged from 10.0-79.4 mg/ml. The study provides a scientific basis for the folkloric use of Millettia aboensis roots.

Keywords: Millettia aboensis, antimicrobial activity, phytochemical analysis methanol extract, aqueous extract.