In-vitro antioxidant capacity and cytoprotective/cytotoxic effects upon Caco-2 cells of red tilapia (Oreochromis spp.) viscera hydrolysates

The antioxidant capacity of red tilapia viscera hydrolysates (RTVH) with different degrees of hydrolysis (DH) as well as their ultrafiltration membrane fractions, were analyzed using different chemical assays. Their protective effects against oxidative stress were evaluated using H2O2-stressed human intestinal differentiated Caco-2. The highest antioxidant capacity was obtained with a DH of 42.5% (RTVH-A) and its < 1 kDa fraction (FRTVH-V). RTVH-A and FRTVH-V did not show cytotoxic effects at a concentration of <= 0.5 mg/mL,prevented the decrease in cell viability, and suppressed intracellular reactive oxygen species (ROS) accumulation induced by H2O2. However, pretreatment with RTVH-A after adding H2O2, showed a greater decrease in glutathione levels. Moreover, FRTVH-V allowed for a recovery close to that of control levels of cell proportions in the G1 and G2/M cell cycle phases; and a decrease in the cell proportion in late apoptosis. These results suggest that RTVH-A and FRTVH-V can be beneficial ingredients with antioxidant properties and can have protective effects against ROS-mediated intestinal injuries.