Potential effects and mechanism of flavonoids extract of Callicarpa nudiflora Hook on DSS-induced colitis in mice

•Flavonoids of C. Nudiflora is the potential drugs for the treatment of colitis.•Flavonoids of C. Nudiflora recoveres intestinal damage in mice.•Flavonoids of C. Nudiflora regulates the structure of intestinal flora.•Flavonoids of C. Nudiflora regulates NF-κB and MAPK pathways. Callicarpa nudiflora Hook (C. nudiflora) is an anti-inflammatory, antimicrobial, antioxidant, and hemostatic ethnomedicine. To date, little has been reported regarding the activity of C. nudiflora against ulcerative colitis (UC). In this study, we investigated the effect of a flavonoid extract of C. nudiflora on Dextran Sulfate Sodium (DSS)-induced ulcerative colitis in mice. Mice in the treatment group (CNLF+DSS group) and drug-only (CNLF group) groups were administered 400 mg/kg of flavonoid extract of C. nudiflora leaf (CNLF), and drinking water containing 2.5 % DSS was given to the model and treatment groups. The symptoms of colitis were detected, relevant indicators were verified, intestinal barrier function was assessed, and the contents of the cecum were analyzed for intestinal microorganisms. The results showed that CNLF significantly alleviated the clinical symptoms and histological morphology of colitis in mice, inhibited the increase in pro-inflammatory factors (TNF-α, IL-6, IL-1β, and IFN-γ), and increased the level of IL-10. The expression of NF-κB and MAPK inflammatory signal pathway-related proteins (p-p65, p-p38, p-ERK, p-JNK) was regulated. The expression of tight junction proteins (ZO-1, OCLDN, and CLDN1) was increased, while the content of D-LA, DAO, and LPS was decreased. In addition, 16S rRNA sequencing showed that CNLF restored the gut microbial composition, and increased the relative abundance of Prevotellaceae, Intestinimonas butyriciproducens, and Barnesiella_intestinihominis. In conclusion, CNLF alleviated colitis by suppressing inflammation levels, improving intestinal barrier integrity, and modulating the intestinal microbiota, and therefore has promising future applications in the treatment of UC.