Study of encapsulation of polyphenols on succinyl-chitosan nanoparticles

In this work is reported the study of the preparation of succinyl-chitosan (SCs) nanoparticles by the ionic cross-linking method for polyphenols encapsulation, as well as the theoretical study of the interaction between SCs and polyphenols. Modification of chitosan (Cs) with succinyl groups was carried out through the reaction between the –NH2 groups within the Cs structure and succinic anhydride. The SCs was characterized by FTIR and 1HNMR and a succinylation degree of 26% was obtained. The effect of the weight ratio SCs:TPP in the preparation of the nanoparticles was studied, to select a proper SCs: Tripoliphosphate (TPP) ratio to achieve the smallest particle size. In order to carry out a comparative study, three polyphenols (epigallocatechin-3-gallate (EGCG), propyl gallate (PG) and gallic acid (GA)) with different molecular weights and number of –OH groups, were encapsulated. The encapsulation efficiency and loading capacity for each polyphenol were evaluated. GA showed an encapsulation efficiency of 88%, for EGCG it was 65% and for PG was 27%. SCs–Polyphenol interaction energy behavior is studied through density functional theory (DFT) methods where a structure–binding relationship was found.