NF-κB independent inhibition of lipopolysaccharide-induced cyclooxygenase by a conjugated linoleic acid cognate, conjugated nonadecadienoic acid

10t, 12c-CLA was shown to inhibit COX-2 expression through the NF-κB pathway. In the current study, conjugated nonadecadienoic acid (CNA) was shown to decrease inducible COX-2 protein and mRNA and PGE2 release to the similar extent as 10t, 12c-CLA in Raw264.7 macrophage. However, unlike 10t, 12c-CLA, inhibition of COX-2 mRNA/protein by CNA was independent of the NF-κB pathway. The data indicate the regulation of COX-2 by select conjugated fatty acids and hence their anti-inflammatory actions could operate through different signal transduction pathways.