Anti-proliferation peptides from protein hydrolysates of Pyropia haitanensis

In this study, proteins were extracted from the red macroalga Pyropia haitanensis and hydrolyzed with pepsin and papain. Gel filtration chromatography was performed to separate hydrolysates. Three fractions were obtained from papain-digested hydrolysates, which showed anti-proliferation effects on human breast cancer cells (MCF-7), human liver cancer cells (HepG-2), and human lung cancer cells (A549), with IC50 values of 59.09-272.67 mu g mL(-1). Furthermore, a new peptide QTDDNHSNVLWAGFSR was identified, which had the best inhibition on HepG-2 cancer cells (61.36%), but low inhibition on human normal liver cells LO-2 (22.81%), at 500 mu g mL(-1). This is the first time that anti-proliferative peptides originating from protein hydrolysates of P. haitanensis were isolated and characterized.