Studies on catalytic, antioxidant, antibacterial and anticancer activities of biogenic gold nanoparticles

Biosynthesis of nanoparticles of precious metals has been attaining a surge of interest in recent years. In the present study, phytochemicals present in Areca catechu nut have been used for the synthesis of gold nanoparticles at 300 K, 373 K and under microwave irradiation of 2450 MHz. The synthesized nanoparticles have been characterized using UV-visible, TEM, XRD, and FTIR techniques. Perpetual changes in synthesis conditions are bestowed with appreciable morphological variation. An enhanced formation of monodispersed, spherical gold nanoparticles of size 13.7 nm could be obtained under microwave irradiation. XRD pattern confirms the crystalline nature of the as-synthesized nanoparticles. The biomolecules involved in the reduction and stabilization of nanoparticles have been identified using FTIR spectra. The catalytic efficiency of the synthesized gold nanoparticles of varying size distributions has been portrayed through the degradation of the organic pollutants, Methylene blue, Methyl orange, Eosin yellowish and 4-Nitrophenol. The observed size dependent catalytic activity may aid in the rapid elimination of industrial wastes leading to a green environment. The potential of the phytosynthesized nanogold in scavenging the harmful radical NO and the stable radical DPPH has been evaluated. In addition to its cytotoxic effect on HeLa cell lines, gold nanospheroids synthesized under microwave irradiation have been observed to exhibit an enhanced activity against a broad spectrum of bacterial pathogens as well.