Hinokitiol, a natural tropolone derivative, inhibits TNF-α production in LPS-activated macrophages via suppression of NF-κB

In this study, we examined the modulatory effect of hinokitiol (HK) on the production of tumor necrosis factor (TNF)-alpha, a critical factor involved in skin inflammation and hair follicle apoptosis. HK effectively suppressed TNF-alpha production in lipopolysaccharide (LPS)-activated, macrophage-like (RAW264.7) cells. This compound also diminished mRNA synthesis of TNF-a, indicating that HK-mediated inhibition may occur at the transcriptional level. Moreover, this compound down-regulated the phosphorylation of PDK1, Akt/PKB, and ERK, resulting in a loss of nuclear factor (NF)-kappa B activation, which is detectable by immuno-blotting and reporter gene assays. Therefore, these results suggest that HK may cure hair loss by suppressing factors that promote follicular apoptosis, such as TNF-alpha, in addition to stimulating new hair growth.