Harnessing nature's secrets: Silver nanoparticles from Withania coagulans fruit and root extracts unveil exceptional antioxidant and antimicrobial properties

Nanotechnology, an emerging field, holds significant promise with applications across diverse sectors, including medicine, agriculture, and the biological sciences. To address environmental concerns, the green biosynthesis of silver nanoparticles (AgNPs) using plant extracts is favoured. This study focuses on the formulation and characterisation of AgNPs using extracts from Withania coagulans (Stocks) Dunal, a medicinal plant that holds a unique phytochemical profile. The AgNPs derived from W. coagulans root (WcAgNPR) and fruit (WcAgNPF) extracts were characterised using ultraviolet and visible light (UV-Vis) spectral analysis, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR) spectroscopy. The findings reveal that both WcAgNPR and WcAgNPF exhibit substantial antioxidant potential, with robust iron reducing capabilities and potent 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity. Additionally, they demonstrate strong hydrogen peroxide scavenging abilities. Notably, WcAgNPR outperforms WcAgNPF in the phosphomolybdate assay for antioxidant potential. Both AgNPs display remarkable antimicrobial efficacy, with minimal inhibitory concentrations (MIC) below 10 µg.mL-1 against gram-positive bacteria (Staphylococcus aureus) and noteworthy activity against gram-negative Escherichia coli (WcAgNPF with a MIC of 30 µg.mL-1 and WcAgNPR with a MIC of 60 µg.mL-1). These findings highlight the silver nanoparticles' significant antioxidant and antimicrobial potential, suggesting their potential for in vivo use as antimicrobial agents with minimal oxidative damage.