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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)-α- and interferon (IFN)-γ-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-α and IFN-γ-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. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the immunomodulatory effect of jacaric acid, a naturally-occurring conjugated linolenic acid isomer that can be found in jacaranda seed oil, on the activated human mast cell line-1 (HMC-1). Our previous studies have demonstrated that jacaric acid only exerted minimal, if any, cytotoxicity on normal murine cells. In the present study, jacaric acid at concentrations =100 μM did not exhibit direct cytotoxicity on human peripheral blood mononuclear cells after 72 h of incubation, as determined by the MTT reduction assay. By contrast, jacaric acid could alleviate the calcium ionophore A23187 and phorbol 12-myristate 13-acetate-triggered allergic response in the HMC-1 cells at concentrations that were non-cytotoxic to the HMC-1 cells. Following pre-treatment with jacaric acid, the secretion of two inflammatory mediators, β-N-acetylglucosaminidase and tryptase, as well as the T helper 2 cytokines [interleukin (IL)-4 and IL-13] was significantly reduced in HMC-1 cells. The alleviation of allergic response was accompanied by downregulation of the matrix metalloproteinase-2 and -9 proteins and upregulation of the tissue inhibitor of metalloproteinase-1 protein. Collectively, the results indicated that the naturally-occurring jacaric acid exhibits a suppressive effect on the allergic response in activated human mast cells in vitro, and this could not be attributed to the direct cytotoxicity of jacaric acid on the treated cells. [ABSTRACT FROM AUTHOR]