Antioxidant properties of aqueous selenium nanoparticles (ASeNPs) and its catalysts activity for 1, 1-diphenyl-2-picrylhydrazyl (DPPH) reduction

Abstract

In this work, Aqueous selenium nanoparticles (ASeNPs) was prepared from sodium selenite (Na2SeO3) as a precursor by using gallic acid (GA) as a reducing agent in wet chemical methods. The morphology, particle size, structure, and free radical scavenging (FRS) activity of ASeNPs were characterized by high-resolution transmission electron microscopy (HRTEM), ultraviolet–visible spectroscopy (UV–vis), fourier transform infrared (FTIR), energy-dispersive X-ray spectroscopy (EDAX), dynamic light scattering (DLS), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Synthesized ASeNPs showed uniform sphere-shaped with an average particle size range of 98 nm. EDAX analysis confirmed the existence of selenium in the nanosphere. FTIR results show that hydroxy (-OH), carboxyl (-CO), alkyl (C–H) functional groups on the surface of ASeNPs. The percent scavenging of DPPH of ASeNPs for initial reaction pH 6, 6.5, 7 and buffer 7 was obtained as 80.6%, 84.0%, 83.0% and 73.0% respectively. The DPPH radical scavenging activity of ASeNPs without using any stabilizer and capping agent in this work reached higher than 80% in 1.0 ml of ASeNPs. The percent scavenging of ABTS of ASeNPs for initial reaction pH 6, 6.5, 7 and buffer 7 was obtained as 85.7%, 94.9%, 93.8%, and 75.1% respectively. Apparent rate constant (kapp) for FRS reactions of DPPH increases linearly with an increasing concentration of ASeNPs, an increase in the kapp value was because of the accessibility of more interaction sites of ASeNPs.