Efficacy of different extraction procedures on antibacterial activity of stem bark of Butea monosperma (Lam.) Kuntze

摘要

The search for new antimicrobials of natural origin derived from plants is still very important at present. Over the decades it has been observed that selection of solvents is critical for the extraction of active compounds from plants. In this study, three solvents namely, hexane, chloroform and methanol were employed to extract the active constituents from the stem bark of Butea monosperma (Lam.) Kuntze. High performance thin layer chromatography (HPTLC) was used to separate and establish the active constituents from the bark of the plant. Active constituent were tested for their antibacterial activity against five Gram positive bacteria (Bacillus subtilis, Enterococcus faecalis, Micrococcus luteus, Staphylococcus aureus and S. epidermidis) and seven Gram negative (Aeromonas hydrophila, Alcaligenes faecalis, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella typhimurium) bacteria using agar well diffusion assay. Relatively low minimum inhibitory concentrations (MIC) were obtained for hexane and methanol extracts compared to chloroform extracts. Our findings revealed that hexane and methanol could be used as best solvents for extraction of antimicrobial compounds from B. monosperma bark.