Preparation and optimization of a resveratrol solid dispersion to improve the physicochemical properties and oral bioavailability of resveratrol

Insights into structure-antioxidant activity relationships of polyphenol-phospholipid complexes: The effect of hydrogen bonds formed by phenolic hydroxyl groups

Five typical polyphenols (catechin, quercetin, gallic acid, ellagic acid, and chlorogenic acid) were selected to form non-covalent complexes with soy lecithin, confirmed by 1H NMR, X-ray, DSC, and molecular docking simulations. Subsequently, the impacts of complexation on the antioxidant activity were evaluated using five different methods to analyze structure-activity relationships. The results showed that the complexation with phospholipids would not reduce the antioxidant activity of polyphenols, mainly attributed to three mechanisms: (i) the amphiphilic nature of phospholipids enhanced polyphenol solubility via encapsulation and amorphous state stabilization, (ii) hydrogen-bond networks immobilized reactive hydroxyl groups while shielding them from oxidative environments, and (iii) phospholipid-mediated kinetic solvent effects reduced the bond dissociation energy and optimized sustained antioxidant release kinetics. This study provides deeper insights into the interaction mechanisms between polyphenols and phospholipids and supports wider potential applications of polyphenols.

Dual Strategy for Improving the Oral Bioavailability of Resveratrol: Enhancing Water Solubility and Inhibiting Glucuronidation

Resveratrol (RES) suffers from poor water solubility and extensive metabolism, which lead to low bioavailability. A phospholipid complex (PC) containing RES and a UDP-glucuronosyltransferase (UGT) inhibitor was prepared to address these two limiting factors, thereby improving RES bioavailability. First, 11 natural active ingredients metabolized by similar enzyme subtypes to RES were screened in a glucuronidation assay in liver microsomes. Then, glycyrrhetinic acid (GA), the strongest inhibitor, was prepared with RES in a PC. RES-PC was prepared as a control. As expected, the water solubility and the cumulative dissolution of RES were significantly enhanced by RES-PC and RES/GA-PC. Compared with the RES group, the AUC_0-10 of RES and resveratrol-3-glucuronide (R-3-G) in the RES/GA-PC group showed increases of 2.49- and 1.70-fold, respectively, with the proportion of RES absorption to total absorption increasing 1.45 times. These results demonstrated that RES/GA-PC could improve the bioavailability of RES by increasing its water solubility and inhibiting its glucuronidation.