Effects of Alpinetin on Intestinal Barrier Function, Inflammation and Oxidative Stress in Dextran Sulfate Sodium-Induced Ulcerative Colitis Mice

Background: Alpinetin is a flavonoid isolated from Alpinia katsumadai Hayata that has demonstrated anti-inflammatory, antibacterial and anti-tumor activities. However, alpinetin has not been widely studied in amelioration of inflammatory bowel disease. The study aimed to investigate the role of alpinetin on intestinal epithelial tight junctions, oxidative stress and Nrf2/HO-1 signaling pathway in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. Methods: A total of 40 mice were divided into 5 groups (n = 8/group): control group, DSS group (received 3% DSS), and low, medium and high-dose treatment groups (3% DSS + alpinetin 25, 50 and 100 mg/kg). The disease activity index (DAI), histological scores, epithelial tight junctions, oxidative stress factors, and Nrf2/HO-1 signaling pathway in the colon were determined. Results: Alpinetin improved DAI, colonic shortening, histological scores and myeloperoxidase activity compared with the DSS group. The expression of occludin and zonula occludens-1 were upregulated by alpinetin, whereas the expression of claudin-2 was reduced. Moreover, alpinetin inhibited the level of malondialdehyde, and increased the level of superoxide dismutase. Nrf2/HO-1 signaling pathways were also found to be activated. Conclusion: Alpinetin is associated with decreased intestinal inflammation and oxidative stress dose-dependently, and also regulated the expression of tight junctions between cells in UC mice. The findings of our study may shed light on the use of alpinetin in the treatment of UC.