Green synthesis of silver nanoparticles using Vernonia amygdalina plant extract and its antimicrobial activities

Abstract

The green nanoparticles synthesis method from leaves extract revealed full an economical, sustainable and eco-friendly method. In this study, the leaf extract of Vernonia amygdalina was as a reducing and capping agent for the synthesis of silver nanoparticles (AgNPs). M/DW binary solvent was selected for its relatively better extraction performance than methanol, ethanol, distilled water and ethanol/distilled water. Furthermore, the effect of solvent ratio of M/DW, precursor concentration, ratio of silver nitrate (AgNO3) to plant extract, temperature, time and pH on the synthesis of AgNPs was carried out. Greenly synthesized Agents was confirmed using UV–Vis spectroscopy and characterized by XRD and FT-IR. Besides, its antimicrobial activities were also evaluated using agar diffusion techniques. The UV–Vis spectra showed specific Surface Plasmon Resonance (SPR) absorption peaks between 411 nm and 430 nm which revealed the formation of AgNPs during the synthesis. The nanoparticle synthesis was further confirmed by XRD analysis. Phytochemical screening test and FT-IR analysis of V. amygdalina leaves extract revealed the existence of phenolic, Tannin, saponins and flavonoid groups, which capped the nanoparticles during the synthesis. The antibacterial activities of the synthesized AgNPs were evaluated against Gram-positive bacteria (S. pyogenes and S. aureus) and Gram-negative bacteria (E. coli and P. aeruginosa) and higher inhibition zones were observed.