Evaluation of Antibacterial and Antioxidant Activities of Biosynthesized Zinc oxide Nanoparticles usingAqueous Extract of EriobotryaJaponica Seeds

Recently, much attention has been paid to the biosynthesis of nanoparticles (NPs) due to their eco-friendly, cost-effective, and easily applied nature. This study aimed to synthesize zinc oxide (ZnO) NPs using Eriobotrya Japonica seed aqueous extract. Moreover, it was attempted to evaluate their antioxidant and antibacterial activities.

Initially, the Eriobotrya Japonica seed aqueous extract was prepared, and the total phenolic and flavonoid contents were measured in this study. After the preparation of ZnO NPs by the extract, the antioxidant activity of ZnO NPs was evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging method. In addition, the antibacterial activities of the extract and NPs were determined using a disc diffusion method against Staphylococcus aureus gram-positive bacteria and Escherichia coli gram-negative bacteria. Ethics code:  Ir.ausmt.rec.1398.11.33

The results showed that aqueous extract had a specific amount of phenolic and flavonoids (9.86 mg/g and 27 mg/g dry weight of extract, respectively). Moreover, the synthesized ZnO NPs were <30 nm in diameter with a good absorption rate at 349 nm. In addition, the antioxidant activity of the extract and NPs indicated an increase in the antioxidant activity following an increase in the concentration. Furthermore, the anti-bactericidal activity results demonstrated an appropriate antibacterial activity against S. aureus, whereas the aqueous extract had no antibacterial activities.

The findings revealed that the biosynthesized ZnO NPs had appropriate antioxidant and bactericidal activities. This suggests that the NPs can be used in various sectors, such as cosmetic products and food packaging, as a potential alternative to synthetic antibiotics.