Neem (Azadirachta indica) leaf extract mediated synthesis of zinc oxide nanoparticles (ZnO NPs) and their antibacterial activity

Abstract

In this study, we prepared zinc oxide nanoparticles using a quick, safe, and cost-effective method by reducing Zn(NO3)2·6H2O solution with Neem (Azadirachta indica) leaf extract. Qualitative phytochemical screening and FT-IR spectroscopy measurements were employed to validate the presence of active biomolecules such as Flavonoids, phenols, alkaloids, terpenes and tannic compounds. FT-IR, UV–Vis, and XRD spectroscopic techniques were utilized to fully analyze the biosynthesized nanoparticles. The spectrum of UV–Visible spectroscopy indicated UV–Vis spectrum of 321 nm. FTIR spectra showed the absorption peak for the stretching vibration of Zn–O at 544 cm−1. The results obtained supported the formation of ZnO NPs employing A. indica leaf extract as a reducing and stabilizing agent. X-ray diffraction spectrum analysis was also used to investigate the crystal structure. The particle size of ZnO NPs was calculated using the Scherrer’s equation and the result was found to be 19.16 nm. Furthermore, the antibacterial potential of zinc oxide nanoparticles against two clinical strains of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria was examined by paper disc diffusion method. The result showed a significant inhibition zone of 18 mm against E. coli and an inhibition zone of 15 mm against S. aureus.