Phytofabrication of zinc oxide nanoparticles with advanced characterization and its antioxidant, anticancer, and antimicrobial activity against pathogenic microorganisms

The biofabrication of zinc oxide nanoparticles by renewable sources is thought to be ecologically acceptable, clean, and nontoxic. Willow plant (Salix tetrasperma) in the current study was used to measure its ability to create zinc oxide nanoparticles (ZnONPs). The created ZnONPs were characterized via several techniques namely ultraviolet visible (UV–Vis) spectroscopy, transmission electron microscope (TEM), scanning electron microscope (SEM), dynamic light scattering (DLS), atomic force microscopy (AFM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infra-red (FTIR) spectroscopy, and Raman spectroscopy. Disk diffusion method was applied to assess the antimicrobial activity of ZnONPs. Free radical scavenging potential of different concentrations of ZnONPs and plant extract was measured by 1,1-diphenyl-2-picryl hydrazyl (DPPH) method. Cytotoxicity against prostate cancer cells (Pc3) via the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide)-based assay. Sharp peak was observed at 310 nm indicating the creation of ZnONPs. XRD results and Raman analysis confirmed the natural crystal structure of ZnONPs and stable zinc oxide (ZnO) structure. Good antibacterial activity of ZnONPs was observed against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, and Salmonella typhimurium with inhibition zones 28.10 ± 0.17, 23.83 ± 0.29, 28.33 ± 0.58, 23.83 ± 1.04, 28.33 ± 0.58, and 33.83 ± 0.76 mm, respectively. Candida albicans was also inhibited with inhibition zone 23.67 ± 0.29 mm, while Mucor circinelloide and Aspergillus fumigatus not inhibited by ZnONPs. A promising antioxidant activity of ZnONPs was observed with IC₅₀ 8.73 µg/mL compared with the IC₅₀ 15.91 µg/mL of the plant extract. Cytotoxicity test indicated the activity of ZnONPs against Pc3.