Poncirin alleviates the symptoms of dextran sulfate sodium-induced colitic mice

We previously reported that anti-inflammatory properties of poncirin, isolated from fruit of Poncirus trifoliata, might be the result from the inhibition of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α) and interlukin-6 (IL-6) expression via the down-regulation of NF-κB binding activity. In this study, we investigated whether poncirin has an inhibitory effect on the production of pro-inflammatory mediators ex vivo and whether poncirin could relieve the symptoms of dextran sulfate sodium (DSS)-induced colitis in mice model of inflammatory bowel disease. Poncirin significantly inhibited the productions of NO, IL-6 and TNF-α in lipopolysaccharide (LPS)-induced mouse peritoneal macrophage. In addition, poncirin-treated mice when compared to control mice not receiving treatment recovered better from the weight loss caused by DSS-induced colitis. Changes in disease activity index (DAI) of poncirin-treated mice were also more favorable than for control mice and were comparable with mice treated with a typical anti-inflammatory-drug, 5-aminosalichylic acid (5-ASA). In addition, suppression of plasma NO and IL-6 productions of poncirin-treated mice was also observed in DSS-induced colitis. These results suggest that poncirin has potentially useful anti-inflammatory effects mediated by suppression of inflammatory mediator productions.