Biogenic synthesis and spectroscopic characterization of silver nanoparticles using leaf extract of Indoneesiella echioides: in vitro assessment on antioxidant, antimicrobial and cytotoxicity potential

Natural synthesis of metal nanoparticles is gaining more attention in recent years. This article demonstrates the phytochemical synthesis of silver nanoparticles (AgNPs) by using Indoneesiella echioides (L) leaf extract as a reducing and stabilizing agent. Biosynthesis of AgNPs was monitored by UV–visible spectroscopy which revealed intense surface plasmon resonance bands at 420 nm. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction were employed to identify various functional groups and crystalline nature of AgNPs. High-resolution transmission electron microscopy studies demonstrated that synthesized particles were spherical with average size of ~29 nm. In vitro antioxidant effects were analyzed by 2,2′-Azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH), which exhibited 69 and 71 % of scavenging activity, respectively. The antimicrobial activity of green AgNPs displayed better zone of inhibition against selected human pathogens. The present study also investigated the toxicity effect of biogenic AgNPs against human lung adenocarcinoma cancer cells (A549) and normal human epithelial cells (HBL-100) in vitro, and the inhibitory concentrations (IC50) were found to be 30 and 60 µg/mL, respectively. Herein, we propose a previously unexplored medicinal plant for the biological synthesis of AgNPs with potent biomedical applications.