Abstract:

Strongylocentrotus nudus is one of the major species of economic sea urchin in China. It has high food and
medicinal value due to its delicious taste and nutritional richness. In this work, bioactive peptides were prepared by
enzymatic hydrolysis of Strongylocentrotus nudus gonads with papain and their bioactivities were investigated. Five
fractions with molecular weight distribution of < 1, 1–3, 3–5, 5–10 and <10 kD were obtained by ultrafiltration of the
hydrolysate. Results showed that all the peptide fractions at a final concentration of 200 μg/mL could promote lymphocyte
growth. Moreover, at this concentration, all the peptides except the fraction of < 1 kD could inhibit the growth of HeLa
cells, and promote the phagocytic function of peritoneal macrophages. At 50 μg/mL, all the peptide fractions could protect Chang
liver cells against oxidation induced by tert-butyl hydroperoxide; butylhydroperoxid through direct and indirect pathways. All
the peptides could inhibit the classical complement pathway activity in a dose-dependent manner. All the above results suggested
potential regulatory activity on cellular and humoral immune function and anti-oxidant capacity. The multiple bioactivities of these
peptides deserve further investigation.

Key words: sea urchin, peptide, bioactivities, HeLa cell