Biosynthesis, antimicrobial and in vitro antiproliferative activities of silver/silver chloride nanoparticles from mixed fruit extracts of Capsicum frutescens and Tamarindus indica

Abstract

Silver/silver chloride nanoparticles were formed by treating mixed extracts of Capsicum frutescens and Tamarindus indica (CT) with 5 mM AgNO₃ in sunlight for 120 min, which was confirmed by a UV–visible spectrophotometer as a comparatively sharp peak was observed at 465 nm. Crystalline properties of Ag/AgCl-NPs were examined through X-ray diffraction method. The nearly spherical shape of Ag/AgCl-NPs was confirmed by scanning electron microscopy and the average size of particle was approximately 72.2 nm. The existence of elemental Ag was assessed with an energy-dispersive spectrometer whereas two major functional groups as capping agents were obtained using Fourier transform infrared spectroscopy. The CT extract-mediated Ag/AgCl-NPs showed moderate toxicity determined against brine shrimp nauplii with an LD₅₀ value of 177.9 μg/mL. The nanoparticles showed 92.6 % growth-suppressive activity against S. aureus, 81.1 % against S. boydii, 60.3 % against S. dysenteriae, and 50 % against E. coli at the concentration of 50 µg/mL in disc diffusion assay. The recorded free radical scavenging activities of Ag/AgCl-NPs were 55.79 % at 60 µg/mL for DPPH and 64.93 % at 100 µg/mL for ABTS. MTT colorimetric assay confirmed the antiproliferative activity of Ag/AgCl nanoparticles against EAC and MCF-7 cells (42.7 % and 47.4 %) at concentrations of 50 µg/mL and 128 µg/mL, respectively.