Sulfuretin is one of the main flavonoids produced by Rhus verniciflua, which is reported to inhibit the inflammatory response by suppressing the NF-kappa B pathway. Because NF-kappa B activation plays a pivotal role in the pathogenesis of allergic airway inflammation, we here examined the effect of sulfuretin on an ovalbumin-induced airway inflammation model in mice. We isolated sulfuretin from R. verniciflua. Sulfuretin was delivered intraperitoneally after the last ovalbumin challenge. Airway hyper-responsiveness, cytokines, mucin, and eosinophilic infiltration were analyzed in bronchoalveolar lavage fluid and lung tissue. A single administration of sulfuretin reduced airway inflammatory cell recruitment and peribronchiolar inflammation and suppressed the production of various cytokines in bronchoalveolar fluid. In addition, sulfuretin suppressed mucin production and prevented the development of airway hyper-responsiveness. The protective effect of sulfuretin was mediated by the inhibition of the NF-kappa B signaling pathway. Our results suggest that sulfuretin may have therapeutic potential for the treatment of allergic airway inflammation. (C) 2010 Elsevier Inc. All rights reserved.