The present study involves the green synthesis of zinc oxide nanoparticles ZnO NPs using three different solvents for plant extract of ethanol (EtOH), methanol (MeOH), and double distilled water (ddH2O) in a method that is rapid, cost-effective, and environmentally friendly. The novelty of this study was creating ZnO NPs from Washingtonia filifera plant seed extract. Green fabricated ZnO NPs were characterized via UV–Vis spectroscopy, Fourier transform infrared (FT-IR), energy-dispersive spectroscopy (EDX), and X-ray diffraction (XRD). SEM data showed the efficacy of palm seed extract metabolites in fabricating spherical shape of ZnONPs, with an avarage size of 50, 71.6, and 81.6 nm for ddH2O, EtOH, and MeOH Zn ONPs, respectively. FT-IR analysis showed varied absorption peaks related to fuctional group of plant extract and nanoparticle formation. Moreover, data analysis revealed that the antimicrobial activity against pathogenic Gram-positive and Gram-negative bacteria and fungi was dose-dependent and exhibited variable inhibition zone values.
In comparison to the plant extract alone, which provides minimum antimicrobial activity, the ZnO NPs prepared from this plant inhibit bacterial activity more efficiently. MeOH-ZnO NPs formed a maximum clear zones, 23.5 ± 0.3, 26.0 ± 0.3, and 19.8 ± 0.3 mm, at highest concentrations of 500 µg/ml against S. aureus, P. aeruginosa, E. coli, respectively. EtOH-ZnO NPs exhibit 82.2, 82.2, and 67.2% of mycelial inhibition after 6 days of treatment with ZnO NPs for A. niger, A. fumigatus and S. apiospermum, respectively. Also, biosynthesized ZnO NPs showed a potent anti-inflammatory activity of were dose-dependent. The present anti-bacterial activities were increased as the NPs concentration increased. The W. filifera-mediated ZnO NPs showed strong antimicrobial activity against clinical pathogens compared to standard drugs. This suggests that plant-based synthesis of NPs can be an excellent strategy for developing versatile and eco-friendly biomedical products.