Characterization and antitumor activity of protein hydrolysates from Arthrospira platensis (Spirulina platensis) using two-step hydrolysis

摘要

In this study, Arthrospira platensis proteins were hydrolyzed using sequential digestion with alcalase/papain. Gel filtration chromatography was used to separate hydrolysates and five fractions D1-D5 were obtained. D1 showed the strongest antitumor effects on MCF-7 and HepG-2 cells, with the IC50 values of 31.25 and 49.36 mu g mL(-1), respectively. Subsequently, three small peptides with antitumor activities, including AGGASLLLLR, LAGHVGVR, and KFLVLCLR, were identified. The truncated peptide LCLR exhibited better activity than its parent peptide KFLVLCLR, with the inhibition rate of > 60 % on MCF-7 and HepG-2 cells, but little cytotoxicity on L-O2 cells (similar to 6 %), at 500 mu g mL(-1). Moreover, D1 was confirmed to inhibit solid tumor growth in HepG-2-bearing nude mice, with the best inhibition achieved at day 11, up to 39.75 % at the dosage of 200 mg kg(-1) day(-1). Taken together, the identified peptides possessed potent antitumor activities but low cytotoxicity on normal cells and could be used as nutraceuticals and pharmaceuticals.