Icariin derivative inhibits inflammation through suppression of p38 mitogen-activated protein kinase and nuclear factor-kappaB pathways.

In this study we investigated the anti-inflammatory effects of an icariin derivative (3,5-dihydroxy-4'-methoxy-6'',6''-dimethy1-4'',5''-dihydropyrano[2'',3'':7,8]-flavone). We found that this icariin derivative inhibits tumor necrosis factor-alpha (TNF-alpha) production, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expression, and protein expression in lipopolysaccharide (LPS) stimulated RAW264.7 macrophages. It also alleviates paw edema induced by carrageenan in mice. To clarify the molecular mechanisms underlying these anti-inflammatory effects, we examined the effects of this compound on the phosphorylation of mitogen-activated protein kinase (MAPK), phosphorylation of inhibitory kappaBalpha (IkappaBalpha), and nuclear translocation of p65 subunit of nuclear factor (NF)-kappaB, and found it suppresses the activation of p38 MAPK and inhibits translocation of NF-kappaB p65 to the nucleus through decreasing the phosphorylation of IkappaBalpha. As a result of these properties, this icariin derivative can be considered as a potential drug for inflammatory diseases.