Biogenic Synthesis of Silver Nanoparticles Using Saraca indica Leaf Extract and Evaluation of Their Antibacterial Activity

The present study reports an unprecedented biogenic method for the synthesis of silver nanoparticles (AgNPs) using leaf extract of Saraca indica and characterized their antibacterial activity. We have also focused on the biosynthesis mechanism of AgNPs. Plant leaf extract has water soluble organic materials which help in the reduction of silver ions and stabilization of AgNPs. Aqueous solution of silver nitrate was treated with leaf extract of Saraca indica for the formation of AgNPs. The surface plasmon resonance was occurred at 412 nm. The size distribution profile of synthesized AgNPs was analysed by Dynamic Light Scattering (DLS). Transmission Electron Microscopy (TEM) has been done for the measurement of particle size and their morphology. The role of phytochemicals in the reduction of silver ions and defining the framework in which AgNPs are covered and provide steadiness can be determined through Fourier Transform Infrared Spectroscopy (FTIR). TEM micrograph reveals that the size of AgNPs was obtained in the range of 13-50 nm with spherical morphology. X-ray Diffraction (XRD) pattern of the AgNPs exhibited 2θ values corresponding to the silver nanocrystals. Furthermore, the antibacterial activity of synthesized AgNPs against E. coli DH5α was investigated by growth curve and inhibition zone analysis. It was observed that the 20 μg/ml concentration of biogenic AgNPs recorded as minimal inhibitory concentration (MIC) against E. coli DH5α.