Curcumol exhibits anti-inflammatory properties by interfering with the JNK-mediated AP-1 pathway in lipopolysaccharide-activated RAW264.7 cells

Curcumol is one of the major components of the essential oil of Rhizoma Curcumae, a common traditional Chinese medicine with anti-inflammatory properties. However, the anti-inflammatory activity and the underlying molecular mechanisms of this compound remain unclear. In the present study, the anti-inflammation effect of curcumol on lipopolysaccharide (LPS)-induced RAW264.7 cells is demonstrated along with its underlying mechanisms. We show that curcumol inhibits LPS-induced NO production by suppressing iNOS mRNA expression and protein level but not iNOS activity. Moreover, curcumol inhibits LPS-induced production of TNF-α, IL-1β and IL-6 at both the transcriptional and translational levels. Further investigations reveal that these effects mainly act via suppressing JNK-mediated AP-1 rather than the NF-κB pathway; these effects include a decrease in the phosphorylation level of JNK and a direct inhibition of the activity of p-JNK. These data provide scientific molecular evidence that curcumol may be a potential lead compound for a novel anti-inflammatory drug because of its inhibitory activity on the production of various inflammatory mediators.