The novel peptides ICRD and LCGEC screened from tuna roe show antioxidative activity via Keap1/Nrf2-ARE pathway regulation and gut microbiota modulation

In this study, a high-throughput strategy combined with MALDI TOF/TOF-MS and Discovery Studio 2017 was developed to screen peptides with certain functions from hydrolysate. Two dominant peptides, Ile-Cys-Arg-Asp (ICRD) and Leu-Cys-Gly-Glu-Cys (LCGEC), were predicted to have antioxidant activity by Discovery Studio 2017. Then the activity in vitro of peptides had been confirmed via DPPH assay. Both two peptides decreased apoptosis induced by UVB treatment in HaCaT cells and altered Keap1/Nrf2-ARE pathway transcription. Furthermore, the antioxidant activity of LCGEC was achieved after 6-week treatment in mice via regulating the Keap1/Nrf2-ARE pathway, inhibiting the release of proinflammatory cytokines, increasing the abundance of 3-indolepropionic acid and short-chain fatty acids production in feces and modulating gut microbiota composition. This study provided two tuna roe peptides with in vitro and in vivo antioxidant activity.