Hydrothermal Green Synthesis of Silver Nanoparticles using Azadirachta indica A. Juss. Fruit Juice for Potential Antibacterial Activity

This study employed a green, eco-friendly and convenient hydrothermal method for the synthesis of stable silver nanoparticles (Ag NPs) using neem (Azadirachta indica A Juss) fruit extract, which also acts as a reducing and capping agents. Since neem fruits has been found to have various medicinal applications, this fruit has been chosen in this paper to obtain Ag NPs. The Ag NPs were characterized by PXRD, UV–Vis diffuse reflectance spectra (DRS), FTIR, FESEM-EDAX, and HRTEM analysis. UV–Vis DRS spectra studies provided sufficient evidences for the formation of Ag NPs. The major role of functional groups present in the synthesis and stabilization of the NPs was obtained from FTIR studies. The PXRD and HRTEM investigations clearly demonstrated the crystalline nature of the NPs. From the HRTEM images, the Ag NPs were found to be spherical and of nearly uniform size with an average size of 13 nm. Further, Ag NPs were subjected to the agar disc diffusion antimicrobial assay (Mueller–Hinton Agar testing) against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria. The test results showed the potent antibacterial activity of NPs for Gram-positive bacteria is higher than that the Gram- negative bacteria