Biosynthesis of Silver nanoparticles using Plumbago zeylanica Leaves extracts and their bio-efficacy

Abstract

The present study was intended to optimize the protocol for the synthesis of silver nano particles of Plumbago zeylanica Linn. leaves extracts and evaluate their bioefficacy against six different human pathogens. The aqueous silver ions exposed to the leaves extracts and the silver nanoparticle synthesis was established by the change of colour of leaves extracts from greenish to reddish brown. The in vitro synthesised silver nanopeptides were further confirmed by using UV-Vis spectroscopy and examined their antibacterial activity against S. aureus, B. subtilis, S. pyogenes (Gram positive), K. pneumoniae, M. morganii, P. aeruginosa (Gram negative).  To find the inhibition concentrations, the antibacterial activity was performed by agar well diffusion method with five different concentrations (10 – 50 µg/ml) against six different pathogens viz., S. aureus, B. subtilis, S. pyogenes (Gram positive), K. pneumoniae, M. morganii, P. aeruginosa (Gram negative).  The zone of inhibition was directly consonance with the concentrations of P. zeylanica SNPS. 50 µl of P. zeylanica SNPs showed maximum zone of inhibition (25±0.5 mm) against K. pneumoniae, next to that, 23±0.5 mm zone of inhibition was observed against M. morganii and minimum zone of inhibition (9 ± 0.3 mm) was obtained aginst S. pyogenes. The results revealed that the AgNP’s extract of P. zeylanica showed higher zone of inhibition against Gram negative bacteria than the Gram positive bacteria.