Antimicrobial efficacies of methanol extract of Asteracantha longifolia, Ipomoea aquatica and Enhydra fluctuans against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Micrococcus luteus

Abstract

Present experiment was executed to investigate the antimicrobial efficacy of Asteracantha longifolia, Ipomoea aquatica and Enhydra fluctuans leaf extracts on four pathogenic bacterial strains, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Micrococcus luteus. Methanol extract of herbs were used at four different concentrations for examining the antibacterial efficacy on bacterial strains using agar-cup-diffusion assay and measuring the diameter (mm) of the clear zone around the cup. The mean values of the clear zone in S. aureus were 1.17 to 3.85, 1.02 to 1.45 and 1.14 to 2.58 times greater in A. longifolia, I. aquatica and E. fluctuans, respectively compared to that of the remaining bacteria. This results obviously implied that the methanol extract of three types of herbs have a highest antimicrobial efficacy against the S. aureus over P. aeruginosa, E. coli and M. luteus. Though, no clear zone was found in the methanol extract of the A. longifolia and E. fluctuans againstP. aeruginosa, but the mean values of the clear zone of the I. aquatica extract exhibited 7.4 mm in P. aeruginosa and showed 28 to 118%, 12 to 96% and 200 to 250% higher than that of the remaining two herb extracts. Therefore, it may be concluded that A. longifolia andE. fluctuans herbs have no activity against the P. aeruginosa, whereas I. aquatica exerted a higher magnitude of antimicrobial activity against the tested four types of bacterial species than that of the rest two herb extracts due to compositional variation in the active biomolecules of three herbs.