Manel Azzi, Ibtissam Laib, Abderrhmane Bouafia, Abir Benaissa, Ifriqya Medila, Nawal Houmri, Ammar AL‐Farga, Salah Eddine Laouini
ABSTRACT Zinc oxide nanoparticles (ZnO NPs) were synthesized using Olea europaea leaf extract as a reducing and stabilizing agent, providing a sustainable alternative to chemical methods. X‐ray diffraction confirmed a hexagonal wurtzite structure with lattice parameters a = b = 3.2490 Å, c = 5.2070 Å, and a crystallite size of 22.14 ± 1.24 nm, indicating high phase purity. Fourier‐transform infrared spectroscopy identified hydroxyl, carbonyl, and carboxylate groups from the extract, with a Zn–O bond at 433 cm −1 , verifying NP formation. Scanning electron microscopy revealed spherical NPs with a ∼27 nm size distribution peak, while energy‐dispersive x‐ray spectroscopy confirmed purity (54.95% Zn, 45.05% O). UV–visible spectroscopy showed an absorption peak at 350 nm, with direct and indirect bandgap energies of 2.80 and 1.50 eV, respectively, and an Urbach energy of 0.341 eV, suggesting suitability for photocatalysis and optoelectronics. The NPs exhibited dose‐dependent antioxidant activity, with ferric reducing antioxidant power of 20.65 ± 2.1 µg AA/µg and total antioxidant capacity of 31.94 ± 1.7 µg GA/µg, at 200 µg/mL. Antimutagenic tests showed 76.27% inhibition against 1‐nitropyrene (TA98 strain). Antibacterial studies demonstrated complete suppression of Escherichia coli and Staphylococcus aureus growth, highlighting potential for biomedical and environmental applications.