In vitro antioxidant activities of copper mixed oxide (CuO/Cu₂O) nanoparticles produced from the leaves of Phoenix dactylifera L

Biosynthesis of antioxidant nanoparticles using plant extracts is a simple, rapid, environmentally friendly, and cost-effective approach. In this study, in vitro antioxidant copper mixed oxide nanoparticles (CuO/Cu₂O) were prepared from the alcoholic extract of Phoenix Dactylifera L. and different aqueous concentrations of CuSO₄·5H₂O. The composition, crystallinity, morphology, and particle size of CuO/Cu₂O NPs were tuned by increasing the CuSO₄·5H₂O concentration from 4 to 10 mM. Ultraviolet–visible (UV–Vis) and Fourier-transform infrared (FTIR) spectroscopy confirmed the reduction of CuSO₄·5H₂O and the formation of the CuO/Cu₂O NPs. X-ray diffraction (XRD) confirmed the crystalline nature of the CuO/Cu₂O NPs with a crystallite size varying from 18 to 35 nm. Scanning electron micrographs (SEM) showed that the CuO/Cu₂O NPs have a spherical morphology with particle sizes ranging from 25 to 100 nm. The best antioxidant CuO/Cu₂O NPs have a phase ratio of about 1:1 CuO/Cu₂O with a half-maximal inhibitory concentration (IC₅₀) of 0.39 mg/ml, an iron-containing reducing antioxidant power (FRAP) of 432 mg EFeSO₄/100 mg NPs, and a total antioxidant capacity (TAC) of 65 mg EAA/gNPs. The results suggest that the synthesized CuO/Cu₂O NPs are excellent antioxidants for therapeutic applications. Graphical abstract: (Figure presented.)