Bio-augmentative antibacterial activity of Pongamia pinnata (L.) gall extract with lemongrass oil formulation against selected Gram-negative bacteria

The present study evaluates the antimicrobial activity of ethanolic and aqueous extract of Pongamia pinnata (L.) normal leaves, gall-removed leaves and galls. They were tested against five Gram-negative human pathogenic bacterial strains; all strains have unique antimicrobial resistance and pathogenic properties. Among the different extracts, ethanolic gall extract exhibited a broad spectrum of antimicrobial activities. Based on this feature, we augmented the ethanolic gall extract with lemongrass oil, which produced higher antimicrobial effects than ethanolic gall extracts. The ethanolic gall extracts containing several bioactive metabolites that exhibited a different level of biological activities were validated using the prediction of activity spectra for substances (PASS) server (in silico approach). Using the plant parts, especially galls, to prepare antibacterial agents not only helps to control pathogenic strains of bacteria, but also reduces the wastage of P. pinnata leaves when used for Ayurvedic preparations. Also, it help to reduce the dependence on synthetic antimicrobial drugs