Potent inhibition of the inductions of inducible nitric oxide synthase and cyclooxygenase-2 by taiwaniaflavone

The improper productions of nitric oxide and prostaglandins following the inductions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) are involved in the pathogenesis of chronic inflammation. Selaginella tamariscina is used as an oriental medicine for its anti-inflammatory effects. Here, we isolated taiwaniaflavone from S. tamariscina and investigated whether taiwaniaflavone affects the induction of NOS and COX-2 in RAW264.7 macrophages stimulated with lipopolysaccharide. We found that taiwaniaflavone blocks the transactivations of iNOS and COX-2 genes by blocking the nuclear translocation of p65 and subsequent nuclear factor-kappa B inactivation. It is known that NF-kappa B activation is controlled by the phosphorylation and subsequent degradation of I-kappa B alpha, and in the present study, we found that the phosphorylation and degradation Of I-kappa B alpha were also inhibited by taiwaniaflavone. Our findings indicate that taiwaniaflavone may provide a developmental basis for an agent against inflammatory diseases. (c) 2006 Elsevier Inc. All rights reserved.