Antibacterial Activity of Prepared Zinc Oxide Nanoparticles by Eco-Friendly Method Using Olive Leaves and Roselle Flower Extracts

Abstract

This research looked at the antimicrobial properties of zinc oxide nanoparticles (ZnO NPs) made from roselle flower extracts and olive leaves as part of a green synthesis method. We used field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet-visible (UV–vis) spectroscopy and Fourier-transform infrared (FTIR) spectroscopy to study the morphological, structure and optical properties of ZnO NPs. The Field Emission Scanning Electron Microscopy (FESEM) test revealed that the ZnO NPs (Olive leaves) had round particles with sizes ranging from 29.03[Formula: see text]nm to 53.59[Formula: see text]nm, while the ZnO NPs (Roselle flower) had nanoflakes with sizes ranging from 42[Formula: see text]nm to 80[Formula: see text]nm. By using UV–vis spectroscopy, it was found that the optical energy gap for ZnO NPs derived from olive leaves was about 2[Formula: see text]eV and for ZnO NPs derived from rose flowers it was 2.2[Formula: see text]eV. The antimicrobial properties of ZnO nanoparticles (NPs) were assessed against two types of bacteria: gram-negative bacteria (Klebsiella pneumoniae) and gram-positive bacteria Staphylococcus aureus (S. aureus). Both plant extracts exhibited a maximal inhibitory zone of 21[Formula: see text]mm against gram-positive bacteria, specifically S. aureus.