In this study, novel antioxidant peptides from pancreatin hydrolysate of C-PC were isolated and purified by using a multi-bioassay-guided method. The DPPH and ABTS radical scavenging in vitro and antioxidant zebrafish model in vivo were used to evaluate the antioxidant activities. Furthermore, the underlying molecular mechanisms of these peptides were investigated by measuring the level of ROS, MDA, SOD, CAT and gene expression in Nrf2 signaling pathway.
Total three novel active peptides, MHLWAAK (Met-His-Leu-Trp-Ala-Ala-Lys), MAQAAEYYR (Met-Ala-Gln-Ala-Ala-Glu-Tyr-Tyr-Arg), and MDYYFEER (Met-ASP-Tyr-Tyr-Phe-Glu-Glu-Arg) were isolated and purified from pancreatin hydrolysate of C-PC. These synthesized peptides displayed high DPPH and ABTS radical scavenging ability. In addition, in a zebrafish model, the three peptides significantly protected zebrafish embryos from H2O2-induced oxidative injury without toxicity by inhibiting ROS generation, preventing MDA formation, and upregulating the activities of SOD and CAT. Further experiments showed that these peptides could significantly regulated oxidative stress via activating the Nrf2 signaling pathway.
This study indicates that the antioxidant peptides from C-PC could serve as powerful antioxidants for preventing and treating various diseases associated with oxidative stress.