Green synthesis and biomedical applications of CuO/MgO nanocomposite: Antibacterial, antioxidant, and antidiabetic efficacies

Oxidative stress and its associated complications pose serious threats to human health, demonstrating the pressing need for effective redox-active materials. This study presents the biogenic synthesis of a redox-active Copper oxide/Magnesium oxide (CuO/MgO) nanocomposite using Citrus limonium extract and evaluates its antibacterial, antioxidant, and antidiabetic activities, along with CuO nanoparticles for comparison. X-ray diffraction (XRD) analysis divulges the interwoven CuO and MgO phase in a single matrix with a crystallite size of 44 nm. Fourier transform infrared (FTIR) spectra expose the vibrational bands at 864, 678, and 570 cm −1 , corresponding to Cu O, Mg O, and Cu–O–Mg. Optical analysis reveals a bandgap energy of 1.47 eV for the CuO/MgO composite, higher than 1.29 eV observed for CuO nanoparticles, indicating the improved visible-light absorption. Morphological examination reveals irregular aggregates with porous surface texture of the CuO/MgO composite. X-ray photoelectron spectroscopy (XPS) analysis substantiates the Cu 2+ , Mg 2+ , and O 2− oxidation states of rudiments in the nanocomposite. Biologically, the CuO/MgO nanocomposite exhibits potential antibacterial activity against S. epidermidis and E. coli , with inhibition zones of 27.4 ± 0.15 mm and 25.2 ± 0.1 mm, respectively, and shows enhanced antioxidant activity with IC 50 values of 140.72 ± 0.6 μg/mL. Furthermore, it demonstrates stronger inhibition of α-amylase and α-glucosidase enzymes, 79.8% and 86.1%, respectively, compared to CuO nanoparticles. Overall, this study confirms that the CuO/MgO nanocomposite, synthesized via a green approach, exhibits enhanced structural, optical, and biological properties, making it a promising candidate for biomedical applications targeting oxidative stress-related disorders.