Chrysin (5,7-dihydroxyflavone) is a natural flavone commonly found in many plants. It has previously been shown to be an anti-tumor agent. In this study, we investigated whether chrysin could alleviate the symptoms of dextran sodium sulfate (DSS)-induced colitis in mice and whether chrysin has an inhibitory effect on nuclear factor (NF)-kappa B activation in vitro. A significant blunting of weight loss and clinical signs was observed in DSS-exposed, chrysin-treated mice when compared to vehicle-treated mice. This was associated with a remarkable amelioration of the disruption of the colonic architecture, a significant reduction in colonic myeloperoxidase (MPO) activity, and a decrease in the production of inflammatory mediators such as nitric oxide (NO), prostaglandin (PG) E-2, and pro-inflammatory cytokines. In addition, chrysin inhibited tumor necrosis factor (TNF)-alpha-induced activation of NF-kappa B in IEC-6 cells. These findings suggest that chrysin exerts potentially clinically useful anti-inflammatory effects mediated through the suppression of NF-kappa B activation. (C) 2009 Elsevier Inc. All rights reserved.