Plant mediated green synthesis, characterization and biological study of silver nanoparticles from Ocimum gratissimum aqueous leaf extract

Ocimum gratissimum is traditionally used as antibacterial medicine and accumulates many antioxidant phytochemicals. The study here, expanded this traditional usage with the green biosynthesis of silver nanoparticles achieved using Ocimum gratissimum leaf extract as a reducing and capping agent. The green synthesis of Ag NPs reaction was carried out using 2mL of Ocimum gratissimum leaves extract added to 50mL aqueous solution comprising 85 mg of silver nitrate The effect of temperature on the synthesis of Ag NPs was examined using room temperature (25 0C) and 60 0C. The silver nanoparticles were formed in 20 min by stirring at room temperature. In this case, a deep brown color was developed. The successful formation of silver nanoparticles was further confirmed by UV–Vis and SEM analysis. The characteristic peaks of the UV-vis spectrum and SEM confirmed the synthesis of Ag NPs as the UV spectrum revealed that the maximum absorption peak was at absorbance of 0.99 with corresponding wavelength (λ max) at 500 nm and the SEM micrograph of biosynthesized Ag NPs showed relatively face centered cubic structure, well distributed without aggregation and an average size of about 28nm with 10% of Ocimum gratissimum leaf extract in 1.5 mM Ag nitrate concentration. The biosynthesized Ag NPs exhibited potential antibacterial activity against human pathogenic bacteria. The result clearly suggest that the green biosynthesized Ag NPs can constitute an effective antibacterial agent.