European Journal of Biomedical and Pharmaceutical Sciences

GREEN SYNTHESIS OF ZINC OXIDE NANOPARTICLES USING THE OUTER LAYER OF Allium cepa L. AND THE EVALUATION OF ITS ANTIOXIDANT CAPACITY

Ezealisiji Kenneth M.* and Chioma Nnadi

ABSTRACT

The green synthesis approach of synthesizing nanoparticle is one that is rapid, less toxic to the environment, uses materials that are easily accessible and is more cost effective than the chemical synthesis and physical synthesis approaches. In this study, Zinc oxide nanoparticles were synthesized from the outer layer of Allium cepa L. using the green synthesis method. The synthesized nanoparticles were characterized through the use of UV-Vis spectrophotometry, Fourier Transform Infrared spectroscopy (FT-IR), Dynamic light scattering (DLS), Transmission Electron Microscope (TEM), Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) analyses. The antioxidant activity was evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity assay with Ascorbic acid as the reference standard for the assay. The size range of the synthesized nanoparticles was 28- 38.0 nm and they were found to be non-smooth but spherical in shape. There was a dose dependent increase in the antioxidant activity of the biosynthesized ZnONP and they were able to inhibit 50% of the DPPH free radical at a 377.242 µg/ml concentration showing good in vitro antioxidant activity. This is the first report on Zinc oxide nanoparticles was being synthesised using the outer layer of Allium cepa L. for use as an antioxidant agent.

Keywords: Nanoparticles, Antioxidant, Onions, Spectroscopy, Zinc Oxide.