Facile green synthesis of rutin-functionalized Au and AgAu nanoparticles: Synergistic bioactivity and computational insights

The sustainable synthesis of multifunctional nanomaterials directly from bioactive phytochemicals remains a major challenge in nanomedicine. Here, we demonstrate for the first time a rapid, green, in situ route to rutin-functionalized gold (Rt-Au NPs) and silver gold bimetallic nanoparticles (Rt-AgAu NPs), employing aqueous rutin as the sole reducing and stabilizing agent. The phenolic –OH and carbonyl (C=O) groups of rutin mediated the reduction of Au¹⁺ and Ag⁺ ions, while its π–π conjugated aromatic framework stabilized the resulting nanostructure. Comprehensive characterization confirmed the nanoparticles crystallinity XRD (X-ray Diffraction), surface functionalization by rutin nanostructures FTIR (Fourier Transform Infrared Spectroscopy) and uniform FEG-TEM (Field Emission Gun Transmission Electron Microscopy), with mean diameters of 20 nm for Rt-Au NPs and 36 nm for Rt-AgAu NPs. Bioactivity profiling revealed that Rt-AgAu NPs outperformed pure rutin and monometallic counterparts, producing inhibition zones up to 28 mm against Escherichia coli, Salmonella typhi, Staphylococcus aureus, and Bacillus subtilis . In antioxidant assays, Rt-AgAu NPs exhibited potent and DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical scavenging (IC₅₀ ≈ 26 µg/mL), while in HL-60 leukemic cells, they induced strong dose-dependent cytotoxicity (IC₅₀ ≈ 40 µg/mL). The enhanced therapeutic performance is attributed to the synergistic interplay between rutin’s polyphenolic chemistry and the bimetallic surface, enabling superior electron transfer, amplified reactive oxygen species generation, bacterial membrane disruption, and activation of pro-apoptotic pathways in cancer cells. This work establishes a scalable, eco-friendly nanoplatform with integrated antimicrobial, antioxidant, and anticancer capabilities, offering a promising blueprint for next-generation phytochemical–nanometal therapeutics. • In-situ green synthesis of rutin(Rt)-functionalized Au and AgAu nanoparticles(NPs) • NPs synthesized by rutin acts as sole reducing and stabilizing agent via OH and C=O • NPs show synergistic effect for superior antimicrobial activity against pathogens. • NPs show strong antioxidant (IC₅₀ ≈ 26 µg/mL) and anticancer effects on HL-60 cells. • Eco-friendly nanoplatform integrates antimicrobial, antioxidant, anticancer use.