Spectroscopic analysis of Citrus reticulata- assisted synthesized ZnO-NPs and evaluation of their antibacterial and antioxidant potential

Improper agro-waste disposal causes significant environmental issues, such as unpleasant odours and infections owing to undesirable microbial growth. Citrus peels have intrinsic antioxidants and antibacterial properties due to naturally occurring bioactive compounds. Current research focuses on the synthesis of facile, cost-effective, and greener zinc oxide nanoparticles (ZnO-NPs) using Citrus reticulata peel extract. Prepared materials were characterized by spectroscopic and microscopic techniques, revealing a crystalline nature, with an average size of ZnO-NPs crystalline size (̴ 24 nm) as confirmed by XRD; irregular, hemispherical, and nanorod-like structures, as observed by FE-SEM and TEM. The functional groups as capping and stabilizing agents present on the surface of NPs, as confirmed by FTIR spectra. The UV–Vis spectrum showed maximum absorbance (λ max ) at 360 nm, and the band gap energy was 3.22 eV as determined from the Tauc plot. Antimicrobial activity was evaluated using a broth microdilution assay against E. coli , S.-typhi , and S. aureus . The effective minimum inhibitory concentration (MIC) of ZnO-NPs was observed for E. coli (0.068 mg/ml). The antioxidant potential of ZnO-NPs was also estimated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, where the effective concentration was observed as EC 50 = 3.50 mg/ml. These findings highlight the potential of ZnO NPs as a promising alternative antibacterial drug candidate for future drug development.