Antimicrobial potentials of Eclipta alba by disc diffusion method

This study was conducted to evaluate the antimicrobial potentials of methanol, petroleum ether, dichloromethane, ethyl acetate, butanol and water extracted samples from the aerial parts of Eclipta alba against nine microbial species. The antimicrobial (antibacterial and antifungal) susceptibility was screened by disc diffusion assay. The tested microbial species were Bacillus cereus, Bacillus subtilis, Candida albicans, Erwinia carotovora, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi and Staphylococcus aureus . The extracts were applied in different concentrations of 1, 2 and 3 mg disc -1 . Analysis of the data revealed that all the six extracts from E. alba showed different ranges of antimicrobial activities. Butanol fraction showed inhibitory activities against all the nine microbial species. Ethyl acetate fraction showed inhibitory effects against all the tested microbial species except B. cereus and S. typhi . Petroleum ether, dichloromethane, methanol and water extracted samples had varying levels of inhibitions against some of these microorganisms. The most resistant microbial strain was S. typhi and was not controlled by petroleum ether, dichloromethane, methanol and water extracted samples. The most susceptible Gram positive bacterium was B. subtilis and was inhibited by all the six extracts from E. alba while the most resistant Gram positive bacterium was B. cereus . E. carotovora was the most susceptible Gram negative bacterium while S. typhi and E. coli were highly resistant among the Gram negative bacteria.