The purification and identification of immunoregulatory peptides from oyster (Crassostrea hongkongensis) enzymatic hydrolysate

Oysters, favored as a delicious seafood by people worldwide, contain various nutritional components, especially proteins. In this work, the immunoregulatory peptides were isolated and purified from oyster enzymatic hydrolysate by utilizing anion exchange chromatography and RP-HPLC, and were identified via LC-MS/MS. A proliferation assay, a phagocytosis assay, and TNF-α production, NO production and IL-6 production assays were used to examine the immunoregulatory effects of the two identified peptides. The results indicate that the peptides, DNSIAMESMK (P1) and LLQLGSGR (P2), increased the proliferation rate of macrophages, TNF-α and NO production, IL-6 production, and the phagocytosis ability, but to different degrees; P2, with more hydrophobic amino acids, was more potent than P1. This suggested that these peptides might be potential candidates for developing immunoregulatory functional foods and nutraceuticals.