Comparative Antimicrobial Efficacy of Tulsi Essential Oil and Biosynthesized Silver Nanoparticles

The increasing prevalence of antimicrobial resistance necessitates the exploration of alternative and sustainable antimicrobial agents. Ocimum tenuiflorum (Tulsi) essential oil (EO) possesses well-documented antimicrobial properties but its practical application is limited due to volatility and poor aqueous solubility. In this study, silver nanoparticles were synthesized using Tulsi EO (TEO-AgNPs) via a green synthesis approach and comparatively evaluated the antimicrobial efficacy of TEO and TEO-AgNP against selected bacteria using disk diffusion method. UV–Vis spectroscopic analysis confirmed the formation of AgNPs through the presence of a sharp peak around 410 nm. This distinct peak, free from broadening is characteristic of spherical, monodisperse nanoparticles with high colloidal stability and uniformity. The antimicrobial activity was assessed against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and results demonstrated that TEO-AgNPs exhibited significantly higher antimicrobial activity than Tulsi EO, with larger zones of inhibition of 16.6 mm for E. coli, 17.3 mm for B. cereus and 15.3 mm for S. aureus. The enhanced efficacy of TEO-AgNPs is attributed to the synergistic interaction between silver ions and phytochemicals present in Tulsi. This study highlights the potential of TEO mediated AgNPs as a promising alternative antimicrobial agent for biomedical applications.