Biogenic synthesis of spherical-shaped noble metal nanoparticles using Vicia faba extract (X@VF, X = Au, Ag) for photocatalytic degradation of organic hazardous dye and their in vitro antifungal, antibacterial and anticancer activities

In recent years, industrial wastewater pollution, including organic pollution and harmful bacteria, has endangered the health of humans and other organisms. For this purpose, we designed an eco-friendly and cost-effective technique for the synthesis of noble metal nanoparticles using natural reducing, stabilizing, and capping agents. In the present study, gold (AuNPs@VF) and silver nanoparticles (AgNPs@VF) were synthesized using the extract of Vicia faba, and evaluated for catalytic, antibacterial, antifungal, and anticancer activities. Optimizing synthesis conditions (pH, temperature, reaction time, and concentration) for the best outcomes was conducted. The synthesized AuNPs@VF and AgNPs@VF were characterized using UV–Vis, XRD, EDS, TEM, and FESEM. The homogeneous, oval-spherical morphology and regular products with a size in the range of 30–60 nm were observed from XRD and FESEM techniques. The photocatalytic performance of AuNPs@VF and AgNPs@VF were calculated by degradation of methyl orange (MO) pollution under UV-light irradiation. The AuNPs@VF (91.4%) and AgNPs@VF (80.4%) showed high photocatalytic degradation in the shortest possible time. In order to evaluate antifungal, antibacterial, and drug resistance activities, seven ATCC bacteria (gram-positive and gram-negative bacteria), resistant pathogens strains, and eight fungal strains were selected. The results showed that among these two metal nanoparticles, silver nanoparticles showed a very high antibacterial activity, which can be considered an antibacterial agent. This is despite the fact that the antifungal activity of gold nanoparticles was better than silver nanoparticles. Moreover, the cytotoxicity effects of AuNPs@VF and AgNPs@VF on MCF-7, AGS-3, and normal Beas-2B cell lines were examined by MTT assay. The cytotoxicity result showed that the biosynthesized AuNPs@VF and AgNPs@VF displayed a significant dose-dependent inhibitory effect with IC50 values of 58.65, 46.38 µg/mL on MCF-7 and 22.91, 9.73 µg/mL on AGS-3, respectively compared cisplatin as the positive control. Also, the results showed that the synthesized nanoparticles acted selectively on the normal cell and were safe on the human epithelial cells.