Mucoadhesive Chitosan-Gum Arabic Nanoparticles Enhance the Absorption and Antioxidant Activity of Quercetin in the Intestinal Cellular Environment.

Quercetin (QUE)-loaded nanoparticles (QCG-NPs) were fabricated by ionic gelation between chitosan (CS) and gum arabic (GA) at pH 3.5. At constant CS (0.5 mg/mL) and QUE (60 μM) concentrations, QCG-NPs (260-490 nm) were prepared uniformly with 0.8-2.2 mg/mL GA and exhibited high QUE encapsulation efficiency (94.8-98.0%) and sustained QUE release (4.42-8.89% after 8 h). Because of the electrostatic interaction between QCG-NPs and the mucin layer, in vitro mucin and cell adhesion of QUE were significantly (p < 0.05) enhanced in QCG-NPs (0.44-0.48 mg/mL and 31.7-78.5%), respectively, and the adhesiveness was significantly (p < 0.05) increased with an increase of GA. Because particle size and adhesion properties affect the surface area and retention time of QCG-NPs at the absorption site, cell permeation of QUE through simple diffusion by QCG-NPs exhibited the same tendency as the adhesion results. These data were verified in cellular antioxidant and in vivo ferric reducing abilities of plasma assays that evaluated the antioxidant activities of QUE absorbed into an intestinal cell model and rat blood, respectively. The results provide a better understanding of QCG-NP absorption and indicate that QCG-NPs with mucoadhesion properties can be an effective delivery system for improving QUE absorption.