Suppressive effect of tamarixetin, isolated from Inula japonica, on degranulation and eicosanoid production in bone marrow-derived mast cells

Background: The aim of this study was to evaluate the inhibitory effect of tamarixetin on the production of inflammatory mediators in IgE/antigen-induced mouse bone marrow-derived mast cells (BMMCs). Materials and methods: The effects of tamarixetin on mast cell activation were investigated with regard to degranulation, eicosanoid generation, Ca2+ influx, and immunoblotting of various signaling molecules. Results: Tamarixetin effectively decreased degranulation and the eicosanoid generation such as leukotriene C-4 and prostaglandin D-2 in BMMCs. To elucidate the mechanism involved, we investigated the effect of tamarixetin on the phosphorylation of signal molecules. Tamarixetin inhibited the phosphorylation of Akt and its downstream signal molecules including IKK and nuclear factor kappa B. In addition, tamarixetin downregulated the phosphorylation of cytosolic phospholipase A(2) (cPLA(2)) and p38 mitogen-activated protein kinase. Conclusions: Taken together, this study suggests that tamarixetin inhibits degranulation and eicosanoid generation through the PLC gamma 1 as well as Akt pathways in BMMCs, which would be potential for the prevention of allergic inflammatory diseases. (C) 2021 Codon Publications. Published by Codon Publications.