2,8-Decadiene-1,10-Diol Inhibits Lipopolysaccharide-Induced Inflammatory Responses Through Inactivation of Mitogen-Activated Protein Kinase and Nuclear Factor-κB Signaling Pathway

Amomum tsao-ko (A. tsao-ko) has been used as a traditional medicine for the treatment of infectious and digestive disorders. In the present study, we report the anti-inflammatory activity and molecular mechanism of 2,8-decadiene-1,10-diol (DDO) isolated from the extract of A. tsao-ko in lipopolysaccharide-stimulated RAW 264.7 cells. DDO treatment inhibited the production of nitric oxide and prostaglandin E₂ by downregulating inducible nitric oxide synthase and cyclooxygenase-2 expression, respectively. Moreover, DDO suppressed the production of pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-α. These inhibitory effects of DDO on the expression of inflammatory proteins were found to be mediated through the inactivation of mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase, c-Jun-N-terminal kinase and p38^MAPK, and inhibition of nuclear factor-κB (NF-κB) pathways including degradation of inhibitor of κB-α and nuclear localization of NF-κB. Taken together, these findings demonstrate the pharmacological roles and molecular mechanisms of DDO in regulating inflammatory responses, and suggest further evaluation and development of DDO as a potent therapeutic agent for the treatment of inflammatory disorders.