Polymer-Stabilized Nanocurcumin as a Functional Nanomaterial: Enhanced Physicochemical Properties, Keap1 Binding and Antioxidant Performance

Curcumin is a natural polyphenol with well-documented antioxidant activity. However, its clinical applicability is limited by poor aqueous solubility and low bioavailability. In this study, polyvinylpyrrolidone coated nanocurcumin (PVP–NCur) was synthesized via a modified solvent–antisolvent precipitation method to enhance its physicochemical and functional performance. The nanoformulation exhibited nanoscale particle size, uniform morphology, partial amorphization and strong drug–polymer interactions, resulting in improved aqueous dispersibility and stability. The PVP–NCur exhibited a drug loading efficiency of 64.7% and was also able to release through a sustained in vitro release (approximately 76% after 48 hours), in accordance with Korsmeyer–Peppas kinetics (R 2 = 0.9913), unlike the burst release with native curcumin. Molecular docking with the Keap1 Kelch domain showed an increase in binding affinity of the PVP-curcumin complex (-9.7 kcal/mol) over free curcumin (-9.0 kcal/mol) which is an improvement in the interaction in the target pocket. The ABTS, CUPRAC, hydroxyl and superoxide scavenging assays were used to functional validate the assertion that PVP–NCur was having a significant antioxidant activity which was significantly higher than the Cur. All these results indicate that polymer assisted nanoencapsulation improves the structural stability, release profile and antioxidant properties of curcumin, all of which show its promise in being a sophisticated antioxidant nanomaterial system.