Synergistic Therapeutic Potential of Resveratrol–Quercetin Loaded Selenium Nanoparticles: Synthesis, Characterization, and In Vitro Pharmacological Evaluation

Chronic diseases such as diabetes, inflammation, and oxidative stress continue to pose major global health challenges, while conventional therapies remain limited by poor bioavailability and side effects. Natural polyphenols like resveratrol and quercetin are well known for their antioxidant, anti-inflammatory, and antidiabetic properties, yet their clinical potential is restricted due to rapid metabolism and low solubility. Nanotechnology-based approaches offer a promising solution by enhancing stability, solubility, and targeted delivery of such bioactive compounds. In this study, resveratrol–quercetin functionalized selenium nanoparticles (QR-SeNPs) were synthesized using a green reduction method, with the phytochemicals serving as both reducing and stabilizing agents. The nanoparticles were characterized by UV–Vis spectroscopy, SEM, FTIR, DLS, zeta potential, and XRD, confirming spherical morphology, nanoscale size (200–300 nm), good colloidal stability (–30 to − 40 mV), and predominantly amorphous structure. Biological evaluations revealed that QR-SeNPs exhibited strong anti-inflammatory activity, achieving ~ 80% inhibition of protein denaturation at 50 µg/mL, alongside potent antioxidant activity with ~ 90% scavenging in DPPH and H₂O₂ assays. In antidiabetic assays, they demonstrated significant enzyme inhibition (81% for α-amylase and 75% for β-glucosidase), comparable to standard drugs. Cytotoxicity assessment showed minimal lethality at therapeutic concentrations, with moderate effects observed only at higher doses. These findings indicate that green-synthesized QR-SeNPs represent a multifunctional and biocompatible nanoplatform with strong potential for managing oxidative stress, inflammation, and diabetes, warranting further in vivo and mechanistic investigations.