Synthesis of biogenic silver nanoparticles from polyphenolic Brassica nigra and their potential antifungal, antibacterial, antioxidant, and anticancer activities

Abstract

Green synthesis of silver nanoparticles (AgNPs) has consistently revolutionised the field of nanotechnology, and bio-based AgNPs have emerged as efficient therapeutic tools in biomedical science. The present work focused on the synthesis and characterisation of eco-friendly AgNPs from Brassica nigra (BN), and the evaluation of antibacterial, antifungal, anticancer, and antioxidant activity in the MCF-7 human breast cancer cells. The characteristics of BN-AgNPs was studied using ultraviolet-visible (UV-Vis) spectroscopy, particle size analysis, electro kinetic/zeta potential analysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Elemental composition was determined using energy-dispersive spectroscopy (EDX). UV-Vis spectroscopy confirmed the formation of BN-AgNPs. The TEM micrographs showed that BN-AgNPs were spherical and well distributed in the solution without aggregation. Anticancer activity was determined at different BN-AgNPs concentrations in the MCF-7 cell line with the maximum cytotoxic effect observed at 100 μg/mL. The synthesised BN-AgNPs demonstrated strong antifungal and antibacterial activities against all microbial strains examined with varying degrees. The scavenging action on free radicals by BN-AgNPs showed strong antioxidant efficiency with DPPH, nitric oxide, superoxide, and hydroxyl radicals at different concentrations. The green synthesis of BN-AgNPs is comparatively simple, eco-friendly, and safer than conventional methods; and the observed anticancer activity is suggestive of the role of biogenic BN-AgNPs as potential therapeutic agents for cancer therapy.