Green Synthesis and Characterizations of Copper Oxide Nanocomposite and Nanoparticles Using Rubus Idaeus Leaves Extracts and Their In Vitro Antioxidant and Anticholinergic Activities

In the present study, copper oxide (CuO) nanoparticles and a sodium alginate–based copper oxide nanocomposite were synthesized via a green approach using Rubus idaeus leaf extract at 60 °C for 3 h, and their structural and morphological properties as well as biological activities were systematically investigated. In characterization studies, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscope (SEM) methods were used. According to XRD results, the Debye-Scherrer method was used to determine the nanocrystallite sizes of copper oxide nanoparticles (121.39 nm) and nanocomposite (103.78 nm). The size of some copper oxide nanoparticles, as determined by SEM analysis, was approximately 95 nm. FT-IR spectra and XRD patterns exhibiting characteristic copper oxide vibrations provide strong evidence for the formation of copper oxide-based nanoparticles. In particular, the FT-IR peak at 602.29 cm-1 was assigned to Cu–O stretching vibrations, indicating the successful formation of copper oxide nanoparticles. In this study, for the first time, the antioxidant and anticholinesterase activities of CuO nanoparticles and a sodium alginate–based CuO nanocomposite incorporating Rubus idaeus were evaluated. The nanocomposite exhibited significantly stronger antioxidant activity than CuO nanoparticles, as evidenced by consistently lower IC50 values and a pronounced dose-dependent radical-scavenging capacity, although both systems were less potent than vitamin C. This enhanced antioxidant performance is attributed to the synergistic interaction between sodium alginate and retained bioactive phytochemicals within the composite matrix. Furthermore, both CuO nanoparticles and the nanocomposite exhibited inhibitory effects against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with the nanocomposite showing greater inhibition than nanoparticles alone. While the inhibitory potency was modest relative to galantamine, the improved activity of the nanocomposite highlights the beneficial role of composite formation. These findings reveal a clear structure–activity relationship between antioxidant capacity and cholinesterase inhibition, underscoring the potential of CuO nanocomposites as multifunctional candidates for Alzheimer’s disease prevention strategies.