Green Synthesis of Zinc Oxide Nanoparticles Using Pistacia lentiscus L. Leaf Extact and Evaluating their Antioxydant and Antibacterial Properties

Pistacia lentiscus leaf extract has been used as a reducing and capping agent for the green production of zinc oxide nanoparticles (ZnO NPs) to evaluate their antioxidant and antibacterial properties. The optical and structural properties were determined by ultraviolet–visible (UV–Vis) spectra, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). In the UV–Vis spectra, an absorption peak at 310 nm was observed, whereas the FTIR spectra revealed a peak at 680 cm⁻¹, attributed to the vibration of ZnO NPs and confirmed their formation. X-ray analysis showed the crystalline quality of the ZnO product, with well-defined peaks on the (002), (100), and (101) planes, confirming a hexagonal structure (JCPDS-file: 36-1451). The grain size of the ZnO NPs was approximately 33.90 nm in diameter. Using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (EDS), the morphology of the nanoparticles resembled dried cotton, whereas EDS confirmed the presence of zinc (Zn) and oxygen (O). The evaluation of antioxidant activity involved the DPPH test, thin-layer chromatography (TLC) bioautography, and spectrophotometric assay. The methanolic extract exhibited high antiradical potential, followed by aqueous, etheric, and finally ZnO NPs. Testing the antibacterial activity against two Gram-positive bacterial strains (Staphylococcus aureus and Bacillus cereus) and two Gram-negative strains (Escherichia coli and Pseudomonas aeruginosa) involved determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The results showed that zinc oxide nanoparticles displayed considerable antibacterial effects compared with crude extracts, demonstrating inhibition zones of (24 ± 1) mm and (20 ± 2) mm, respectively, against E. coli and P. aeruginosa, with a bactericidal effect evident by a MBC/MIC ratio of 2.