Nanoscience and nanotechnology are the study and application of extremely small particles and can be used across all the field of science. Recently, nano particles have been used in catalysis, electronics, optics and a number of industries including pharmaceutical and agriculture. Green synthesis of silver nanoparticles is consider as simple, cost effective, biocompatible, less toxicity to cell and eco friendlytechnique. In the present study,we have adopted a technique of green synthesis of silver nanoparticles using leaf extracts of a common medicinal plant i.e. Tulsi (Ocimum sanctum). Theleaf extract was act as a bio-reducer for synthesis of silver nanoparticles (AgNPs). The synthesized AgNPs were characterized using UV-Vis absorption spectroscopy and the absorption maximum was recorded at 651nm. The capping actionof bio moleculeson AgNPs was characterized by Fourier Transform Infra Red Spectroscopy (FTIR). The shape and size of the AgNPs were examined with XRD and scanning electron microscopy (SEM). The XRD analysis indicated the crystalline nature of AgNPs and the SEM photography apparent that the AgNPswerespherical in shapecoated with biomolecules. The anti-bacterial activity of AgNPs was investigated againsta Gram-negative bacterium (E. coli) and a Gram-positive bacterium (Pseudomonas aeruginosa) using agar well diffusion method. The synthesized AgNPs were inhibitory effect on both the experimental bacteria. The present work can be concluded that biomolecules present in Tulsi leaf was a potential bio-reducer for synthesis of AgNPs and the synthesized AgNPshad efficacy as bactericidal activity.

Keywords: Biosynthesis; Silver Nanoparticles (AgNPs); FTIR; SEM; Antimicrobialactivity.