Sida cordata assisted bio-inspired silver nanoparticles and its antimicrobial, free-radical scavenging, tyrosinase inhibition, and photocatalytic activity (4 in 1 system)

This study presents the successful application of Sida cordata (SC) extract in the renewable bio-inspired green synthesis of silver nanoparticles (AgNPs). The aqueous-alcoholic extract of S. cordata (aerial part) was effectively used for the silver nanoparticles (AgNPs) green synthesis. Physiochemical techniques, such as UV-Vis, FT-IR, XRD, FE-SEM, and HR-TEM analyses were applied to characterize the green synthesized AgNPs. UV-vis spectra showed characteristic plasmon resonance spectra with the maximum at 447 nm; the crystalline nature of SC-AgNPs was confirmed by XRD. Shape, size, and morphology were examined by FE-SEM and HR-TEM and the results confirmed the spherical shape of particles with an average diameter of about 48 nm. The presence of alcohols or phenols, carboxylic acids, ketones, amine functional groups were revealed by FTIR. In vitro biological activity studies portrayed that the synthesized SC-AgNPs have potential antimicrobial activity against Gram(-)ve and Gram(+)ve bacteria in a dose-dependent manner, dose-dependent antioxidant activity against DPPH (75.47 +/- 2.5%) and a dose-dependent inhibition of tyrosinase (98.25 +/- 1.25% at a dose of 110 mu g/ml), moreover, the nanoparticles show excellent photocatalytic activity for methylene blue dye degradation. The AgNPs synthesized here were considered a 4 in-1 system.