Anti-Inflammatory Effects of Compounds from in HaCaT Human Keratinocytes.

The root bark of has been reported to have anti-sclerotic, anti-inflammatory, antioxidant, neuroprotective, hepatoprotective, and cytotoxic activities. In the present study, the effect of 16 compounds from on tumor necrosis factor-α+interferon-γ-treated HaCaT cells were investigated. Among these 16 compounds, 11 decreased IL-6 production and 15 decreased IL-8 production. The six most effective compounds, namely, steppogenin (), cudraflavone C (), macluraxanthone B (), 1,6,7-trihydroxy-2-(1,1-dimethyl-2-propenyl)-3- methoxyxanthone (), cudraflavanone B (), and cudratricusxanthone L (), were selected for further experiments. These six compounds decreased the expression levels of chemokines, such as regulated on activation, normal T cell expressed and secreted (RANTES) and thymus and activation-regulated chemokine (TARC), and downregulated the protein expression levels of intercellular adhesion molecule-1. Compounds , , , , and inhibited nuclear factor-kappa B p65 translocation to the nucleus; however, compound showed no significant effects. In addition, extracellular signal regulatory kinase-1/2 phosphorylation was only inhibited by compound , whereas p38 phosphorylation was inhibited by compounds and . Taken together, the compounds from showed potential to be further developed as therapeutic agents to suppress inflammation in skin cells.