The inhibitory activity of atractylenolide Ш, a sesquiterpenoid, on IgE-mediated mast cell activation and passive cutaneous anaphylaxis (PCA)

Ethnopharmacological relevanceAT Ш, a sesquiterpenoid, is the major component of Atractylodes japonica Koidz that has been used as a traditional oriental medicine.Aim of the studyWe investigated the anti-allergic activity of AT Ш and its mechanism of action.Materials and methodsThe released amount of β-hexosaminidase in mast cells, a key parameter of degranulation, was measured. Anti-allergic potential of AT Ш was evaluated using passive cutaneous anaphylaxis in vivo. The anti-allergic mechanism of AT Ш was investigated by immunoblotting analysis, RT-PCR and measurement of [Ca2+]i in mast cells.ResultsAT Ш significantly inhibited IgE/Ag-mediated degranulation with an IC50 value (36±4 μM) in RBL-2H3 cells without affecting cell viability. It also suppressed IgE/Ag-mediated passive cutaneous anaphylaxis (PCA) response with an ED50 value (65±41 mg/kg) in vivo. AT Ш suppressed the production of interleukin (IL-4) and tumor necrosis factor (TNF)-alpha mRNAs more potent than the Src-family kinase inhibitor PP2 in RBL-2H3 cells at all concentrations. In order to elucidate the anti-allergic mechanisms of AT Ш in mast cells, we examined the activated levels of signaling molecules. AT Ш inhibited the phosphorylation of Lyn, Fyn, Syk, LAT, PLCγ, Gab2, Akt, p38, and JNK kinases expression. IgE/Ag-mediated [Ca2+]i elevation was significantly inhibited by AT Ш.ConclusionsOur study suggests that AT Ш might be used as a therapeutic agent for allergic diseases.

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