Synthesis Of Zinc Oxide Nanoparticle Using Leaf Extract Of Lippia Adoensis (Koseret) And Evaluation Of Its Antibacterial Activity

Abstract

In this study synthesis of zinc oxide nanoparticle was done using biological/green method from indigenous ‘Koseret’ Lippia adoensis leaf extract which is endemic medicinal plant and cultivated in home gardens of different regions of Ethiopia. The synthesized ZnO Nanoparticles were analyzed and confirmed, using Thermogravimetric analysis (TGA), X-ray diffraction (XRD), Scanning Electron Microscope (SEM) with Energy dispersive X-ray analysis (EDX), UV-Visible and Fourier Transform Infrared spectroscopy (FTIR). Furthermore, this study also evaluated the antibacterial activity of the synthesized ZnO nanoparticles against clinical and standard strains of Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus (S. aureus), and Enterococcus feacalis by disc diffusion method. According to this study, ZnO nanoparticles synthesized using Lippia adoensis leaf are wurtzite hexagonal structure with an average crystallite size of 18.5 nm at 1:1 reactant ratio is obtained from XRD results. The SEM reveals spherical, nanorod and flake type morphology of nanoparticles and Energy Dispersive X-ray analysis confirms the formation of highly pure zinc oxide nanoparticles. From UV-Visible spectroscopy, band gap energy of 3.42eV is obtained in the near visible region at the wavelength of 362 nm for 3:2 ratio ZnO nanoparticles. ZnO nanoparticles synthesized using Lippia adoensis leaf extract showed promising result against both gram-positive and gram-negative bacterial strains with maximum inhibition zone of 14 nm and 12 nm, respectively in uncalcinated form.