Inhibitory effect of taxifolin on mast cell activation and mast cell-mediated allergic inflammatory response

The aim of the present study is to investigate the anti-inflammatory and anti-allergic effects of taxifolin on mast cells and mast cell-mediated allergic reaction. We assessed the effect of taxifolin on the activation of bone marrow-derived mast cells (BMMCs) and rat basophilic leukemia (RBL)-2H3 cells induced by immunoglobulin E (IgE)/antigen (Ag), and the activation of human mast cell line (HMC-1) induced by PMA plus A23187. Taxifolin inhibited degranulation, generation of leukotriene C₄ (LTC₄), production of interlukin-6 (IL-6), and expression of cyclooxygenase-2 (COX-2) through blocking intracellular Ca²⁺ mobilization, phosphorylation of phospholipase Cγ (PLCγ) and mitogen-activated protein kinases (MAPKs), translocation of cytosolic phospholipase A₂ (cPLA₂) and 5-lipoxygenase (5-LO), and Akt/IKK/NF-κB pathway, in BMMC cells. Furthermore, taxifolin suppressed phosphorylation of Syk, but without effect on Fyn and Lyn. Taxifolin also inhibited activation of RBL-2H3 and HMC-1 cells via Akt/IKK/NF-κB and MAPKs/cPLA₂ signal pathway. Treatment with taxifolin attenuated the mast cell-mediated passive cutaneous anaphylaxis (PCA) reaction. Our results suggest that taxifolin might become a potential drug candidate for the treatment of allergic and inflammatory diseases.