Phyto-mediated synthesis of ZnO NPs using guava leaf extract: characterization, antibacterial activity, and hemolysis effect.

The aim of this work was to synthesize zinc oxide nanoparticles (ZnO NPs) using guava leaf extract as a biogenic substance that facilitates NPs production. The obtained ZnO was characterized using FTIR, XRD, SEM, and UV-Vis techniques and assayed for its antibacterial and hemolytic effects. The results revealed a hexagonal phase with a crystallite size of 25.08 nm and an optical bandgap of 3.33 eV. Bioactivity studies indicated dose-dependent activity with comparable antibacterial activity to gentamicin standard drug, higher against S. aureus (gram-positive) than E. coli and K. pneumoniae (gram-negative) bacteria. The hemocompatibility test against erythrocytes confirmed a nontoxic substance up to 500 μg/mL at which the hemolysis value, under the experimental condition, was 3.2%. These results support the benefit of the synthesized guava extract-mediated ZnO, with a perspective application in electrochemical devices and as a safe antibacterial agent. [ABSTRACT FROM AUTHOR]