High Antioxidant Activity and Low Toxicity of Gold Nanoparticles Synthesized With Virola Oleífera: An Approach Using Design of Experiments

Abstract

Metallic nanoparticles synthesized by plant extracts and biomolecules represent one of the most promising frontiers in the antioxidants field. Plant compounds apart from act as reducing agents, also allow functionalizing these nanoparticles having multiple applications in different industries. However, the low reproducibility and the difficulty in size, shape and stability control have made it difficult to produce on a large scale. Here we report an optimization process to obtain gold nanoparticles (AuNPs) from green synthesis using a factorial design aiming to present a controlled synthesis using Virola oleifera as a reductant agent. We evaluate the influence of the reaction time, temperature, stirring rate, pH and extract concentration monitoring the Localized surface-plasmon resonance (LSPR) band shift (Δλ). The nanoparticles were characterized using Zeta potential, UV-vis, DLS, TEM, Raman spectroscopy, FTIR and XRD. The as-synthesized AuNPs were stable and homogenous, octahedral, monodisperse, and in shape and size and showed great antioxidant activity determined with ABTS+ and DPPH. Furthermore, these nanoparticles presented low cytotoxicity. Finally, using the factorial design, we were able to develop an optimal path for green gold nanoparticles with high antioxidant activity, low toxicity and good morphological characteristic.