Suppression of phospholipase Cγ1 phosphorylation by cinnamaldehyde inhibits antigen-induced extracellular calcium influx and degranulation in mucosal mast cells

Antigen-IgE-mediated mucosal mast-cell activation is critical in the development of food allergies. Cinnamaldehyde, a major constituent of Cinnamomi cortex, dose-dependently inhibited the antigen-IgE-induced degranulation of mucosal-type bone-marrow derived mast cells (mBMMCs) and RBL-2H3 cells. Cinnamaldehyde also suppressed the elevation of the intracellular Ca ²⁺ level that is induced by the extracellular Ca ²⁺ influx in antigen-IgE-stimulated mBMMCs. Furthermore, tyrosine phosphorylation of phospholipase C (PLC) γ1, which is a crucial activation switch for the intracellular Ca ²⁺ mobilization in mast cells, was attenuated by cinnamaldehyde. Together, our results demonstrated that cinnamaldehyde suppressed the intracellular Ca ²⁺ mobilization and the degranulation of mucosal mast cells by inhibiting the activity of the IgE receptor-PLCγ-Ca ²⁺ influx pathway. These findings suggest that cinnamaldehyde may have therapeutic potential in mucosal mast cell-related allergic diseases, such as food allergies.