Antioxidant and Anticancer Activities of Enzymatic Hydrolysates of Solitary Tunicate (Styela clava)

The antioxidant and anticancer activities of solitary tunicate (Styela clava) hydrolysate manufactured with different proteases (Alcalase 2.4 L FG, Thermoase PC10F, and pepsin) and optimized by response surface methodology (RSM) were investigated. The hydrolysate produced by Alcalase generally had greater antioxidant and anticancer activities. Two major fractions, F-1 and F-2, were produced by applying Alcalase hydrolysates to Sephacryl S-100 HR gel filtration chromatography. Fraction F-2 with a lower molecular weight (3.6 +/- 0.1 kDa) had higher ABTS and DPPH radical scavenging activities than F-1 (5.0 +/- 1.0 kDa), with IC50 values of 11.4 and 227.5 mu g/mL, respectively. Moreover, fraction F-2 had higher anticancer activitiy, with IC50 values of 577.1, 1,163.3, and 887.2 mu g/mL against AGS, DLD-1, and HeLa cells, respectively. Fraction F-2 was also rich in tyrosine, lysine, arginine, phenylalanine, and histidine. These results suggest that solitary tunicate hydrolysates have significant health-promoting effects with excellent antioxidant and anticancer activities.