AUTHOR=Xu Fenghua , Zhang Yun , Qiu Yuezi , Yang Fanghao , Liu Guoxiang , Dong Xiaolei , Chen Guang , Cao Can , Zhang Qian , Zhang Shanshan , Li Bing 

TITLE=Three novel antioxidant peptides isolated from C-phycocyanin against H2O2-induced oxidative stress in zebrafish via Nrf2 signaling pathway

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.1098091

DOI=10.3389/fmars.2022.1098091

ISSN=2296-7745

ABSTRACT=C-Phycocyanin (C-PC), a phycobiliprotein from Spirulina platensis, has been confirmed to be an effective antioxidant. However, there are few studies on their bioactive peptides. In this study, 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, its antioxidant activities and underlying molecular mechanisms were investigated. These synthesized peptides displayed high 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (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 reactive oxygen species (ROS) generation, preventing malondialdehyde (MDA) formation, and upregulating the activities of antioxidant enzyme activities (SOD, CAT). Further experiments showed that these peptides could significantly regulated oxidative stress via activating the Keap1/Nrf2/HO-1 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.