Anti-allergic effects of sesquiterpene lactones from the root of Aucklandia lappa Decne

Aucklandia lappa Decne, a well-known traditional herbal medicine, is used for the treatment of asthma, rheumatism, coughs, tuberculosis and numerous other diseases. The present study evaluated the inhibitory effects of the three sesquiterpene lactones costunolide, dehydrocostus lactone, and alantolactone, isolated from a 70% methanolic extract of Aucklandia lappa, on the expression of chemokine mRNA in HaCaT human keratinocyte cells. The cytotoxicities of the compounds on HaCaT cells were evaluated using a Cell Counting Kit8 assay. Furthermore, the inhibitory effects of the three compounds on chemokine expression in tumor necrosis factor (TNF)-alpha- and interferon (IFN)-gamma-stimulated HaCaT cells were analyzed by reverse transcription-polymerase chain reaction analysis. Treatment with the compounds caused a significant reduction in the mRNA expression of a range of chemokines, including TARC/CCL17, MDC/CCL22, RANTES/CCL5 and interleukin-8 in TNF-alpha and IFN-gamma-stimulated HaCaT cells. The present study indicated that costunolide, dehydrocostus lactone and alantolactone may have the potential to be used for treating inflammatory skin disorders by suppressing chemokine expression.