Green biosynthesis of <scp>ZnO</scp> nanoparticles using aqueous peel extract of <i>Punica granatum</i> : Influence of zinc acetate concentration on optical properties and biological activity

Abstract The growing demand for natural antioxidants has driven research into sustainable nanoparticle synthesis. This study developed zinc oxide nanoparticles (ZnONPs‐PG) through green synthesis using phenolic‐rich Algerian pomegranate waste extract. Comprehensive phytochemical analysis via LC–MS/MS and GC–MS revealed diverse bioactive compounds including polyphenols (coumaric acid, kaempferol, quercetin), sugars, lipids (β‐sitosterol, squalene), and carotenoids (beta‐carotene). UV–Vis spectroscopy confirmed nanoparticle formation with absorption peaks between 257 and 360 nm, showing direct (2.69–2.58 eV) and indirect (2.32–2.10 eV) bandgap energies. SEM revealed hexagonal morphology, XRD confirmed crystalline wurtzite structure, and FTIR identified characteristic ZnO vibrations (500–900 cm −1 ). Antioxidant capacity was rigorously evaluated through multiple assays. The 20 mM ZnONPs‐PG formulation exhibited notable free radical scavenging activity, with IC 50 values of 4.65 μg/mL (phenanthroline), 4.87 μg/mL (ABTS), 10.60 μg/mL (DPPH), 10.63 μg/mL (reducing power), and 12 μg/mL (SNP). The eco‐friendly synthesis method, together with the enhanced antioxidant activity observed in several assays, indicates potential for applications such as food preservation, nutraceutical formulations, and preliminary biomedical research. Furthermore, this work demonstrates a sustainable approach to valorizing agricultural waste while contributing to the development of nanomaterial science and suggesting possible future industrial antioxidant uses.