Green synthesis of zinc oxide nanoparticles using <i>Ocimum basilicum</i> essential oil: antioxidant and antibacterial activities against pathogenic bacteria

Given the advanced properties of ZnO, this study introduces a novel green synthesis of ZnO NPs using Ocimum basilicum essential oil as a reducing and stabilizing agent, enhancing both sustainability and biological efficacy. The essential oil composition was analyzed using GC/MS/FID, while ZnO NPs were characterized through FT-IR, XRD, SEM-EDS, and UV-Vis spectroscopy. Antioxidant activity was evaluated using DPPH, FRAP, and β-Carotene assays, and antibacterial activity was tested against pathogenic bacteria. GC/MS/FID identified 36 terpene compounds, with α-Pinene (53.33%) as the major component. XRD confirmed ZnO NPs synthesis with an average crystallite size of 37.33 nm. SEM/TEM revealed irregular needle and spherical morphologies. ZnO NPs exhibited moderate antioxidant activity (DPPH IC50: 20.93 µg/mL), while the FRAP assay showed no reaction. In the β-Carotene assay, ZnO NPs had an EC50 of 80.79%. ZnO NPs showed antibacterial activity against S. aureus (16.66 mm) and P. aeruginosa (18.36 mm), with lower inhibition against E. coli. These findings highlight the potential of O. basilicum essential oil for the eco-friendly synthesis of ZnO NPs, demonstrating promising antimicrobial and antioxidant properties with potential biomedical applications.