Antibacterial activity of Artemisia nilagirica leaf extracts against clinical and phytopathogenic bacteria

Background: The six organic solvent extracts of Artemisia nilagirica were screened for the potential antimicrobial activity against phytopathogens and clinically important standard reference bacterial strains. Methods: The agar disk diffusion method was used to study the antibacterial activity of A. nilagirica extracts against 15 bacterial strains. The Minimum Inhibitory Concentration (MIC) of the plant extracts were tested using two fold agar dilution method at concentrations ranging from 32 to 512 mu g/ml. The phytochemical screening of extracts was carried out for major phytochemical derivatives in A. nilagirica. Results: All the extracts showed inhibitory activity for gram-positive and gram-negative bacteria except for Klebsiella pneumoniae, Enterococcus faecalis and Staphylococcus aureus. The hexane extract was found to be effective against all phytopathogens with low MIC of 32 mu g/ml and the methanol extract exhibited a higher inhibition activity against Escherichia coli, Yersinia enterocolitica, Salmonella typhi, Enterobacter aerogenes, Proteus vulgaris, Pseudomonas aeruginosa (32 mu g/ml), Bacillus subtilis (64 mu g/ml) and Shigella flaxneri (128 mu g/ml). The phytochemical screening of extracts answered for the major derivative of alkaloids, amino acids, flavonoids, phenol, quinines, tannins and terpenoids. Conclusion: All the extracts showed antibacterial activity against the tested strains. Of all, methanol and hexane extracts showed high inhibition against clinical and phytopathogens, respectively. The results also indicate the presence of major phytochemical derivatives in the A. nilagirica extracts. Hence, the isolation and purification of therapeutic potential compounds from A. nilagirica could be used as an effective source against bacterial diseases in human and plants.