Indian medicinal plant extracts and its green synthesized metal nanoparticles: a new genre for combating human pathogens

Some common plants in India, which are also considered as weeds, proved to confer strong antimicrobial activity against many human pathogens. They are rich in a wide variety of secondary metabolites, viz. tannins, terpenoids, alkaloids, flavonoids, phenols and quinines. In this study, some urinary tract infecting human pathogenic strains and their non pathogenic laboratory strains collected from Microbial Type Culture Collection and Gene Bank (MTCC), Chandigarh, India, were subjected to some plant leaf extracts. Study revealed significant results. We chose clinical isolates of pathogenic Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonae. We also selected non pathogenic Escherechia coli K 12 and Pseudomonas syringae (MTCC) strain as test organisms. We prepared ethanolic and 70 % methanolic plant extracts of Lippia nodiflora L., Lippia alba (Mill)., Clerodendrum infortunatum (Linn) and Aegle marmelos (Linn) Corr and followed Kirby – Bauer’s disc diffusion method for the experiment. This study revealed both ethanolic and methanolic extracts of all the plants produced significant results against the test organisms. The ethanolic extracts of L. nodiflora being most effective against pathogenic clinical isolate of E.coli with a zone diameter of 12 mm.