Regulation of JAK2/STAT3 and NF-κB signal transduction pathways; Veronica polita alleviates dextran sulfate sodium-induced murine colitis.

Ulcerative colitis (UC) is a major inflammatory bowel disease (IBD) has become a worldwide emergent disease. Veronica polita (VP) is a medicinal herb that has strong antioxidant and anti-inflammatory properties. In the present study, we studied the protective effect of VP on dextran sulfate sodium (DSS)-induced experimental colitis in mice. Phytochemical screening of VP extract demonstrated the presence of high total phenolic and flavonoid contents. Compared with the DSS group, VP significantly reduced clinical symptoms with less weight loss, bloody stool, shortening of the colon, and the severity of colitis was considerably inhibited as evidenced by the reduced disease activity index (DAI) and degree of histological damage in the colon and spleen. Also, treatment with VP considerably decreased the nitric oxide (NO) and malondialdehyde (MDA) level. VP remarkably downregulated the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), inducible nitric oxide synthetase (iNOS) and cyclooxygenase-2 (COX-2) in the colon tissue. Likewise, activation of the signal transducer and activator of transcription 3 (STAT3) and nuclear factor-kappa B (NF-κB) was effectively blocked by VP. Taken together, these results demonstrate that VP has an ameliorative effect on colonic inflammation mediated by modulation of oxidative stress and inflammatory mediators by suppressing the JAK2/STAT3 and NF-κB signaling pathways.