Green Nanotechnology Approach for Synthesizing Silver Nanoparticles from Ocimum sanctum: Characterization and Antimicrobial Evaluation Against Common Waterborne Bacteria

Abstract

The present study explores an eco-friendly approach to synthesizing silver nanoparticles (AgNPs) using aqueous leaf extract of Ocimum sanctum (holy basil) and evaluates their antibacterial efficacy against common waterborne pathogens. The biosynthesis method employed the reducing and stabilizing capabilities of phytochemicals naturally present in the extract, eliminating the need for hazardous chemicals. Visual observation confirmed the formation of nanoparticles through a color change, while UV-Vis spectroscopy indicated surface plasmon resonance peaks between 423–438 nm. Characterization techniques, including FTIR, XRD, and TEM, revealed the involvement of hydroxyl and carbonyl groups in nanoparticle formation, confirmed their crystalline nature, and showed predominantly spherical particles ranging from 12–30 nm. Antibacterial activity was assessed via the agar well diffusion method against Escherichia coli, Salmonella typhi, and Vibrio cholerae. All AgNP formulations exhibited significant antibacterial activity, with formulation F5 showing the highest zones of inhibition, suggesting increased efficacy with higher extract concentration. The study demonstrates the potential of O. sanctum-mediated AgNPs as effective, sustainable antimicrobial agents for combating microbial contamination in water. This green nanotechnology approach offers a promising solution for water disinfection, especially in low-resource and environmentally sensitive settings.