Abstract: Peptides were prepared from the enzymatic hydrolysate of abalone viscera by sequential ultrafiltration and nanofiltration. The effect of the peptides at different concentrations on cell proliferation and apoptosis in MDA-MB-231 human breast cancer cells was investigated in this study. Our results showed that the peptides were composed of 71.62% protein, 3.38% carbohydrate and 11.48% ash. The molecular mass distribution of the peptides ranged from 350 to 1 000 Da, and they were mostly concentrated around 350 Da, suggesting that oligopeptides consisting of two or three amino acids were the major constituents. The peptides at all concentrations (1, 2, 4 and 8 mg/mL) could inhibit cell proliferation in MDA-MB-231 cells in a concentration-dependent manner as assessed by methyl thiazolyl tetrazolium (MTT) assay. The number of adherent cells decreased and the number of round cells increased with increasing peptide concentration. In addition, some cell nuclei were condensed. Flow cytometry showed that the cells treated with the peptides were arrested at the S and G2 phases. The peptides could induce cell apoptosis and necrosis and consequently inhibit cell proliferation in MDA-MB-231 cells. In conclusion, the peptides prepared from abalone viscera have potential as a supplementary ingredient in antitumor functional foods.

Key words: abalone viscera, peptide, MDA-MB-231 human breast cancer cells, cell proliferation