Papaya Peel Extract-Mediated Green Synthesis of Zinc Oxide Nanoparticles and Determination of Their Antioxidant, Antibacterial, and Photocatalytic Properties

This study describes an effective and eco-friendly approach to the synthesis of zinc oxide nanoparticles (ZnONPs) utilizing papaya fruit peel extract (PPE). The structural evaluation and morphological features of synthesized ZnONPs were examined using various physicochemical analyses. The formulated ZnONPs were spherical to hexagonal in shape with ⁓ 170 nm in diameter. ZnONPs exhibited improved antioxidant potential in terms of DPPH radical scavenging activity (IC50 = 98.74 µg/ml) and ferric-reducing potential compared with PPE. The antibacterial activity of ZnONPs was measured against pathogenic strains of Salmonella typhi, Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. The biosynthesized ZnONPs showed potential antibacterial efficacy against all microbes. In addition, ZnONPs exhibited potential photocatalytic activity in rhodamine B degradation in the presence of sunlight. The results indicated that papaya peels, which are these fruit wastes, could be helpful for the green synthesis of ZnONPs with good dose-responsive antioxidant, antibacterial, and photocatalytic activities.