Curcumin in Pectin-Caseinate Enhances Resveratrol Bioavailability

Resveratrol and curcumin, natural plant-derived polyphenols with antioxidant, anti-inflammatory, and anticancer properties, are limited by poor bioavailability and stability. Delivery systems offer an effective strategy to address these limitations. Notably, their co-encapsulation shows synergistic effects, significantly enhancing encapsulation efficiency, stability, and bioactivity. In this study, nanoparticles were prepared from pectin and sodium caseinate to deliver resveratrol and curcumin using a solvent evaporation method combined with electrostatic deposition, and their physicochemical and structural properties were characterized. The nanoparticles (PE-SC-C-RNP) had a narrow size distribution (247.57 nm), low polydispersity index (0.32), and high encapsulation efficiency (95.24 ± 0.76%). Structural analyses indicated that electrostatic interactions between pectin and sodium caseinate formed the nanoparticle outer layer, with resveratrol and curcumin in an amorphous state. In vitro digestion experiments showed that curcumin enhanced the binding of resveratrol to carriers without affecting the release rate of resveratrol or free amino acids, leading to a significant increase in antioxidant activity. Animal model experiments showed that the resveratrol concentrations were greater in the plasma of mice administered PE-SC-C-RNP than those administered nanoparticles encapsulating only resveratrol orally, with a 0.83-1.27-fold increase in the maximal tissue concentration, and better pharmacokinetics. The maximum tissue concentration of resveratrol increased 0.83–1.27-fold in the liver, kidney, and other tissues within 6.0 h of administration. These results demonstrated that pectin sodium caseinate nanoparticles and co-encapsulated curcumin effectively improved the bioavailability of resveratrol for the delivery of bioactive compounds.