Abstract
Sinomenine (SIN), a pure alkaloid isolated from Sinomenium acutum, has been widely used in arthritis for its anti‑inflammatory effect, but little is known about the effect of SIN on human ulcerative colitis (UC). In the present study, the effect and mechanism of SIN was examined in a dextran sulfate sodium (DSS)‑induced murine colitis model, which mimics human UC. Oral administration of SIN significantly suppressed the elevated disease activity index and ameliorated colonic histological damage in a DSS‑induced colitis model. Tumor necrosis factor‑α, interleukin‑6 and inducible nitric oxide synthase levels were also reduced as detected by reverse transcription‑quantitative polymerase chain reaction. In addition, SIN reversed the decreased colon length and colonic superoxide dismutase activity. Furthermore, western blot analysis revealed that nuclear factor‑erythroid 2‑related factor 2 (Nrf2) and its downstream genes, heme oxygenase‑1 and NADP(H) quinone oxidoreductase 1 (NQO‑1), were markedly activated by SIN. The current results indicated that SIN alleviated DSS‑induced colitis in mice, which may be due to its antioxidant properties and was at least in part dependent on the Nrf2/NQO‑1 signaling pathway. Therefore, SIN may have potential applications as a protective drug for patients with UC.