Polymer nanoparticles composed with gallic acid grafted chitosan and bioactive peptides combined antioxidant, anticancer activities and improved delivery property for labile polyphenols

Polymer nanoparticles assembled from gallic acid (GA) grafted chitosan (CS, GA-g-CS for GA grafted CS) and caseinophosphopeptides (CPP) were developed to deliver (-)-epigallocatechin-3-gallate (EGCG) as novel functional foods. The contents of GA in GA-g-CS copolymers were in the range of 26.5 +/- 1.0-126.0 +/- 1.1 mg/g, with the increase of molar ratio of GA to glucosamine in CS. Compared with CS, GA-g-CS possessed much higher solubility under neutral and alkaline environments. Spherical and physicochemical stable nanoparticles assembled from GA-g-CS and CPP were obtained with particle size around 300 nm and zeta potential of less than +30 my. The GA-g-CS-CPP nanoparticles showed strong antioxidant activity and cytotoxicity against Caco-2 colon cancer cells. The EGCG-loaded GA-g-CS-CPP nanoparticles (84-90% for encapsulation efficiency) showed improved delivery property, controlling release of EGCG under simulated gastrointestinal environments, preventing its degradation under neutral and alkaline environments, and amplifying its anticancer activity against Caco-2 cells. (C) 2015 Elsevier Ltd. All rights reserved.