Biosynthesis of A. tokatensis-ZnO nanoparticles from Astragalus tokatensis: multifunctional bioactivity and molecular docking studies targeting xanthine oxidase and LasR.

The development of sustainable nanomaterials with multifunctional bioactivity remains a major challenge in green nanotechnology. Herein, we report for the first time the green synthesis of ZnO nanoparticles (ZnO NPs) using Astragalus tokatensis Fisch. extract as a novel phytochemical-rich reducing and stabilizing agent. In this study, we hypothesized that phytochemical-rich A. tokatensis extract could mediate the synthesis of bioactive ZnO nanoparticles (A. tokatensis-ZnONPs) while simultaneously enhancing their biological performance through surface-bound secondary metabolites. Accordingly, ZnO NPs were synthesized via an eco-friendly route and comprehensively characterized to elucidate their physicochemical properties. The synthesized A. tokatensis-ZnO NPs exhibited remarkable antibiofilm activity, achieving 90% inhibition at the highest tested concentration, and displayed stronger antibacterial activity against Gram-positive bacteria than against Gram-negative bacteria. Significant antioxidant activity was also observed in both DPPH radical scavenging and metal-chelating assays. Furthermore, A. tokatensis-ZnONPs demonstrated moderate photocatalytic efficiency in methylene blue degradation under sunlight irradiation, highlighting their environmental applicability. Molecular docking analyses revealed favourable interactions between representative Astragalus-derived phytochemicals and the selected protein targets, providing preliminary mechanistic insights into the observed biological activities. Collectively, these findings demonstrate that A. tokatensis-mediated ZnO NPs function as multifunctional nanoplatforms integrating antimicrobial, antioxidant, and photocatalytic properties, underscoring their promise for advanced biomedical and environmental applications.