Free radical scavenging activity of zinc oxide nanoparticles biosynthesised using Aspergillus carneus

Abstract

Zinc oxide nanoparticles (ZnO NPs) were confirmed in this work as a good antioxidant source. They were biosynthesised by the preformedbiomass of Aspergillus carneus when contacted with 1 mM zinc nitrate solution of pH 9 after 24 h at 150 rpm and 30°C. The biosynthesisedNPs were moderately distributed, quasi-spherical in shape with clear edges and the average size of 8-12 nm. The NPs retained full stability at4°C for at least six months. Their zeta potential was found to be 18.3 mV. Crystalline nature of the ZnO NPs was suggested from diffractionrings appeared as lighted spots on the selected area electron diffraction pattern and confirmed by the X-ray diffraction analysis. High radicalscavenging activities (RSA) were found against peroxide (O2 2-) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). Good activities were alsorecorded against hydroxyl (OH-) and superoxide (O-2) radicals. This potential RSA can be rendered to the adsorbed biomolecules on theNPs surface especially the phenolic compounds detected by Fourier transform infrared analysis.