Hydrothermal Assisted Green Synthesis of Zinc Oxide Nanostructures using Azadirachta indica Flower Extract and their Antibacterial Activity

Nowadays, researchers are focusing on the development of new, effective antibiotics due to the re-emergence and inherent genetic changes of microorganisms. Metal oxide nanoparticles, in particular, have drawn a lot of attention due to their exceptional antimicrobial properties. Among these, ZnO nanomaterials have been extensively explored for biomedical applications due to their non-toxic, bio-safe nature and cost-effectiveness for human and animal use. Recently, researchers have proposed plant-mediated hybrid processes to synthesize nanoparticles. In this study, ZnO nanostructures were synthesized using aqueous extract of Azadirachta indica flower as a capping and stabilizing agent. The synthesized ZnO nanostructures were characterized via different techniques including X-ray diffractometry, Fourier transform infrared spectroscopy and scanning electron microscopy. Further, the antibacterial activity of ZnO nanostructures was investigated by disc diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The results showed that ZnO nanostructures prepared using fresh neem flowers with the reaction time of 3 hours were highly active against the bacteria.