Corynoline ameliorates dextran sulfate sodium-induced colitis in mice by modulating Nrf2/NF-κB pathway

Corynoline is an active substance extracted from Corydalis bungeana Turcz and exerts a therapeutic effect in multiple diseases by alleviating inflammatory response. The present study sought to elucidate the role of corynoline in ulcerative colitis (UC).The experimental colitis models were induced in BALB/c mice via receiving a drinking water supplemented with 3.5% (I) dextran sulfate sodium (DSS) ad libitum for 7 days.Corynoline administration inhibited body weight loss, colon shortening, disease activity index and colonic pathomorphological changes in DSS-treated mice. Besides, corynoline down-regulated the levels of pro-inflammatory interleukin (IL)-1β, IL-6 and tumor necrosis factor Alpha (TNF-α), as well as decreased myeloperoxidase (MPO) activity in the colon of DSS-treated mice. In addition, severe oxidative stress in the colonic tissues of DSS-treated was mitigated by corynoline treatment. However, these beneficial effects were reversed by a specific nuclear factor E2-related factor 2 (Nrf2) inhibitor ML385 intervention. Further evidence confirmed that corynoline promoted Nrf2 nuclear migration and heme oxygenase-1 gene expression in the colonic tissues of UC mice. Besides, corynoline treatment restrained colonic nuclear factor-kappa B (NF-κB) activation as proved by the decrease in phosphorylation and nuclear translocation of NF-κB.Corynoline ameliorates DSS-induced mouse colitis, which may provide a promising therapeutic strategy for UC treatment.