Antibacterial activity and FTIR characterization of herbal plants collected from north-western Himalayas

The present investigation was carried out to evaluate the antimicrobial impact of seven herbal plants extracts i.e., curry leaf (Murraya koenigii), bana leaf (Vitex negundo), bhavadi leaf (Ocimum basilicum), umre bark (Ficus glomerata), milk thistle seeds (Silybum marianum), mulethi root (Glycyrrhiza glabra), amla powder and amla juice (Emblica officinalis) against six different human pathogenic strains viz. Shigella flexneri, Bacillus cereus, Stenotrophomonas maltophilia, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus. Different extracts were prepared by using the method of aqueous infusions, decoctions and juice. Curry leaves and milk thistle did not show any antimicrobial activity against any strains by well diffusion method as compared to other extracts used in the study. The varying outcomes observed in the antimicrobial activity of the different extracts could be attributed to the different functional groups like ester, alcohol, phenol, alkane, amino, amide, amines, carboxylic acid, ether present in these extracts, as indicated by the Fourier Transform Infrared Spectroscopy (FTIR) analysis. The presence of different functional groups in extracts may have contributed to the differences in efficacy against pathogenic strains. The presence of antibacterial effects of bana, bhavadi, umre, mulethi and amla suggests that it could be used against human pathogenic bacteria and to manage other diseases.