Biogenic CuO, ZnO, and CuO-ZnO nanostructures for antibacterial activity: DFT and molecular docking insights

Plant extract-mediated synthesis of metal oxide nanoparticles (MO NPs) offers a sustainable route for biomedical applications owing to their biocompatibility and eco-friendly production. In this study, copper oxide (CuO), zinc oxide (ZnO) nanoparticles, and novel CuO-ZnO nanocomposites (NCs) were successfully synthesized using phytochemicals derived from Pistacia chinensis leaf extract. The nanostructures were comprehensively characterized by XRD, UV-Vis spectroscopy, SEM, EDX, and FTIR analyses, confirming their crystalline phases and nanoscale spherical to rod-like morphologies. The estimated optical band gaps (1.6–2.74 eV) indicated their suitability for diverse functional applications. Antibacterial evaluation against Escherichia coli and Staphylococcus aureus revealed significant, dose-dependent inhibitory and bactericidal effects. Complementary density functional theory (DFT) calculations provided insight into the electronic structure of the nanomaterials, while molecular docking studies demonstrated strong binding affinities toward key bacterial and cancer-related target proteins, namely S. aureus dihydrofolate reductase (2W9H), E. coli DNA gyrase B (6F86), and estrogen receptor alpha (ERα, 5GS4). This integrated experimental and computational approach underscores the promising antibacterial and anticancer potential of green-synthesized CuO, ZnO, and CuO-ZnO nanostructures as eco-friendly agents for biomedical applications.