Abstract
Tea catechins, the major polyphenolic compounds in green tea are potent antioxidant with numerous attributed health benefits. However, oral administration of the oxidation-sensitive compounds is limited by the harsh environment of the gastrointestinal tract (GIT) and become an important challenge. In this study, self-assembled nanoparticles composed of chitosan (CS) and an edible polypeptide, poly(γ-glutamic acid) (γ-PGA) were prepared for the delivery of tea catechins. The tea catechins-loaded nanoparticles were pH-responsive and demonstrated different tea catechins release profiles in simulated gastrointestinal tract (GI tract) media. Sustained free radical (DPPH and ABTS + ) scavenging assays showed that the antioxidant activity of tea catechins was retained by the nanoparticles. The nanoparticles with a positive surface charge could transiently open the tight junctions between Caco-2 cells and thus increased the paracellular transport of tea catechins. These results demonstrate that CS/γ-PGA nanoparticles can be effective as a carrier for oral delivery of tea catechins with effective antioxidant activity. © 2012 Elsevier Ltd.