Green Synthesis, Characterization and Antimicrobial Activity of Zinc Oxide Nanoparticles from Leave Extracts of Ziziphus spina-christi Plant

Abstract

The escalating incidence of antimicrobial resistance presents a global health challenge, underscoring the need to explore alternative antimicrobial agents. Medicinal plants with their rich history of therapeutic use, provide a source of bioactive compounds which may be effective against resistant microorganisms. Concurrently, nanoparticles derived from metals exhibits remarkable antimicrobial efficacy due to their unique physical and chemical properties. This study aimed at green synthesis, characterization and antimicrobial activity of Zinc nanoparticles from Leave extracts of Ziziphus spina-christi plant. The phytochemical screening was carried out using standard method, antimicrobial activity was done using agar diffusion method. ZnO NPs were successfully synthesized through bio-reduction (using the leaves extract) and characterized using UV-Vis spectroscopy, FTIR, XRD, and SEM techniques. Phytochemical screening revealed the presence of terpenoids, saponins, flavonoids, and tannins. The antimicrobial activity result indicates that extract and ZnO NPs exhibit moderate antimicrobial activity against the selected bacteria and fungi. Notable findings include a zone of inhibition of 22.00 mm against Escherichia coli (E. coli) for Ziziphus spina-christi extract and zone of inhibition of 20.33 mm on Staphylococcus aureus (S. aureus) for ZnO NPs. These findings underscore the potential of Ziziphus spina-christi extracts and green-synthesized ZnO NPs as alternative antimicrobial agents. The characterization of the synthesized ZnO NPs showed a maximum wavelength of absorption at 281 nm with UV-Vis spectroscopy, indicating their successful synthesis. FTIR analysis identified specific functional groups indicated through major peaks at 2918.5 cm^-1 and 2851.4 cm^-1 resulting from methylene C-H asymmetric or symmetric stretch of alkane, 1729.5 cm^-1 resulting from a carbonyl C=O stretch, 1364.2 cm^- alkene –C-H bending, 1315.8 cm^-1 resulting from Amine C-N stretch, 1237.5 cm^-1 resulting from acid C-O stretch and alcohol C-O stretch 1147.0 cm^- which are involved in the bio-reduction and stabilization of the NPs. XRD pattern analysis revealed a crystallite size of 45.73 nm.