Assessment of in vitro antibacterial and antifungal activities of leaf extracts of Melia azedarach Linn

Abstract

The present study was aimed to analyse in vitro, the antibacterial and antifungal activities of the leaf extracts of Melia azedarach. Leaves were extracted using different solvents such as ethanol, methanol and acetone by hot percolation method. Antibacterial and antifungal activity was measured using agar well diffusion assay and broth microdilution methods, respectively against different pathogenic bacteria and fungi. Thin-layer chromatography-directed bioautography was performed to determine the phytochemicals of the extracts and their antimicrobial activity. The gas chromatography-mass spectroscopy analysis was performed for the isolated active components exhibited antimicrobial activity. Among the various extracts tested, ethanol extract showed significant antimicrobial activity and exhibited zone of inhibition of 16 mm against Bacillus subtilis, 15 mm against Staphylococcus aureus, 14 mm against both Vibrio cholerae and Klebsiella pneumoniae, 12 mm against both Escherichia coli and Pseudomonas aeruginosa. The ethanol extract showed minimum inhibitory concentration of 250 μg/ml against both Aspergillus Niger and Candida albicans. Phytocompounds in the ethanol extract were separated using TLC chromatogram and it showed seven spots. The bioautography of TLC chromatogram showed single band exhibited antibacterial activity and phytocompound from this band was isolated and identified as 5,6,7,8-tetrahydro-1,2,4-benzotriazine-3-amine using gas chromatography-mass spectroscopy analyses. The ethanol extract of leaf of Melia azedarach exhibited significant antimicrobial activity and the compound 5,6,7,8-tetrahydro-1,2,4-benzotriazine-3-amine might be responsible for antimicrobial activity.