Elaboration of Cationic Soluble Soybean Polysaccharides-Epigallocatechin Gallate Nanoparticles with Sustained Antioxidant and Antimicrobial Activities

Epigallocatechin gallate (EGCG) is easily oxidized by environmental stress elements, including light, heat, and oxygen; thus, its biological activities can be reduced or even lost when exposed to a natural environment. Here, soluble soybean polysaccharide (SSPS) was successfully etherized by 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC), positively charged to extract cationic SSPS (CSSPS). Nanoparticles based on CSSPS can improve the encapsulation efficiency (EE) and sustained bioactivity of EGCG. The EE of EGCG by CSSPS was improved significantly as compared with that of SSPS due to the electrostatic interactions. Furthermore, the protective and sustained-release effects of CSSPS on EGCG in the EGCG-CSSPS nanoparticles (EGCG-CSSPS-NPs) markedly improved the sustained antioxidant and antimicrobial activities of EGCG, which was confirmed by the results of a salmon-preservation experiment. In addition, cytotoxicity tests showed that EGCG-CSSPS-NPs could effectively inhibit the proliferation of tumor cells but had no obvious toxicity to normal cells.