Green Synthesized Zinc Oxide Nanoparticles Mediated by Dysphania botrys Extract: Structural Characterization and Biological Applications

Abstract

Zinc oxide nanoparticles (ZnONPs) were prepared using Dysphania botrys extract. Successful NPs formation was confirmed by UV-Vis spectroscopy with a characteristic absorbance peak at 365 nm. XRD analysis revealed a hexagonal wurtzite structure with an average crystallite size of 9.96 nm, while FTIR spectra indicated the involvement of plant phytochemicals in nanoparticle stabilization. SEM images showed predominantly hexagonal morphology, and EDX analysis confirmed high purity, with zinc and oxygen as the major elements. GC–MS profiling of the plant extract identified 26 bioactive compounds, with humulane-1,6-dien-3-ol (29.4%) as the most abundant. The biosynthesized ZnONPs exhibited pronounced antibacterial activity against both Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. Brine shrimp assays revealed concentration-dependent toxicity (100% mortality at ≥160 µg/mL), indicating that the biosynthesized ZnONPs had notable general cytotoxic potential, which warrants careful evaluation of environmental and biomedical safety. Meanwhile, DPPH assays revealed concentration-dependent antioxidant activity (58.8% at 200 µg/mL). Green synthesis using plant extracts has been proposed as a more environmentally benign approach and can reduce the use of hazardous reagents, although the resulting nanoparticles may still exhibit toxicity depending on their dose and properties.