Microwave assisted green synthesis of silver nanoparticles using leaf extract of elephantopus scaber and its environmental and biological applications

The fabrication of spherical silver nanoparticles using the phytoreducing agent Elephantopus scaber is reported here. Irradiation of the reaction mixture under a domestic microwave oven enabled the formation of stable silver nanoparticles and was confirmed by UV-vis spectral portrait. Chemical components inherent in the aqueous leaf extract which reduces the monovalent silver were identified by FT-IR spectroscopy. The crystal structure of the synthesized nanoparticles was established as face centred cube by the powder XRD analysis. The TEM images suggest an average particle size of 37.86 nm to the silver nanoparticles. The prepared silver nanocatalysts can successfully reduce various organic nitro compounds, namely, 4-nitrophenol, 2-nitroaniline and 4-nitroaniline. The environmental pollution caused by dyes like eosin Y is effectively wiped off within a short span of time using the prepared nanocatalysts. The free radical quenching efficacy of the plant extract and the silver nanoparticles were checked by employing DPPH assay bestowing ascorbic acid reference. The potential of the nanoparticles as antimicrobials against six human disease causing pathogens were tested through the well diffusion pathway. The newly developed silver nanoparticles produced IC₅₀ value 15.68 ± 0.15 μg/mL on human skin carcinoma cells, A375 and 65.49 ± 0.40 μg/mL on fibroblast cells, L929 when the cytotoxicity is studied employing MTT assay. Elephantopus scaber showed IC₅₀ value 50.55 ± 0.17 μg/mL against A375 cells.