Preparation and antioxidant properties of soluble Antarctic krill protein-rutin complexes

In order to improve the antioxidant activity of Antarctic krill protein, a new polyphenol-protein complex (SAKP-rutin complex) was successfully prepared by grafting rutin onto soluble Antarctic krill proteins (SAKP). The antioxidant capacity of SAKP-rutin complexes was evaluated by measuring its ability to scavenge DPPH^- and hydroxyl radicals. Meanwhile, the protective ability of SAKP-rutin complexes against oxidative damage of HepG-2 cells was determined by using an H₂O₂ induced oxidative damage model. The results showed that the combination of rutin greatly enhanced the ability of SAKP to scavenge free radicals. Compared with natural SAKP, the SAKP-rutin complexes significantly increased the activity of cellular antioxidant enzymes (CAT, SOD and GSH-Px), decreased the production of lipid peroxidation products (MDA) in cells caused by oxidative stress, and finally reduced the damage of oxidative stress to cells. These findings suggest that SAKP-rutin complex is a novel protein resource which will hopefully be applied to developing functional protein food.