Phyto-assisted synthesis of zinc oxide nanoparticles using mango (Mangifera indica) fruit peel extract and their antibacterial activity

Abstract

A facile and eco-friendly procedure was developed to fabricate zinc oxide nanoparticles (ZnO NPs) using an aqueous extract of mango fruit peel (MFP), a by-product of agroindustry. The ZnO NPs were fabricated using zinc acetate as a precursor and MFP extract as a reducing and capping agent in a neutral environment (pH 7). The UV-visible spectrum supported the formation of ZnO NPs, showing a distinctive absorption peak at 368 nm. The presence of a ZnO crystalline phase was identified by X-ray diffraction (XRD) analysis. The Fourier transform infrared (FTIR) evaluation demonstrated that the biomolecules present in the MFP extract actively contributed to zinc ion reduction. According to the scanning electron microscopy (SEM) image, the surface morphology of ZnO NPs showed a mixture of spherical and flake-like shapes with particle sizes ranging from ~20 to ~90 nm. Based on antibacterial analysis using the agar diffusion method, the biosynthesized ZnO NPs at 3% w/v were active against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus with diameter inhibitions of 8, 19, and 10 mm, respectively. In summary, this present work highlights that ZnO NPs can be synthesized using a by-product of agroindustry. More importantly, the biosynthesized ZnO NPs can be applied as an antibacterial agent.