Ergolide, a sesquiterpene lactone extracted from the dried flowers of Inula Britannica, effectively hinders the expression of inducible nitric oxide synthase and cyclo-oxygenase-2 in RAW 264.7 macrophages by deactivating NF-κB.

Ergolide markedly decreased the production of prostaglandin E(2) (PGE(2)) in cell-free extract of LPS/IFN-gamma-stimulated RAW 264.7 macrophages in a concentration-dependent manner, without alteration of the catalytic activity of COX-2 itself.?Ergolide decreased the level of iNOS and COX-2 protein, and iNOS mRNA caused by stimulation of LPS/IFN-gamma in a concentration-dependent manner, as measured by Western blot and Northern blot analysis, respectively.?Ergolide inhibited nuclear factor-kappaB (NF-kappaB) activation, a transcription factor necessary for iNOS and COX-2 expression in response to LPS/IFN-gamma.?This effect was accompanied by the parallel reduction of nuclear translocation of subunit p65 of NF-kappaB as well as IkappaB-alpha degradation.?In addition, these effects were completely blocked by treatment of cysteine, indicating that this inhibitory effect of ergolide could be mediated by alkylation of NF-kappaB itself or an upstream molecule of NF-kappaB.?Ergolide also directly inhibited the DNA-binding activity of active NF-kappaB in LPS/IFN-gamma-pretreated RAW 264.7 macrophages.?These results demonstrate that the suppression of NF-kappaB activation by ergolide might be attributed to the inhibition of nuclear translocation of NF-kappaB resulted from blockade of the degradation of IkappaB and the direct modification of active NF-kappaB, leading to the suppression of the expression of iNOS and COX-2,?which play important roles in inflammatory signalling pathway.