β-eudesmol suppresses allergic reactions via inhibiting mast cell degranulation

The regulatory effect of β-eudesmol, which is an active constituent of Pyeongwee-San (KMP6), is evaluated for allergic reactions induced by mast cell degranulation. Phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187-stimulated human mast cell line, HMC-1 cells, and compound 48/80-stimulated rat peritoneal mast cells (RPMCs) are used as the in vitro models; mice models of systemic anaphylaxis, ear swelling, and IgE-dependent passive cutaneous anaphylaxis (PCA) are used as the in vivo allergic models. The results demonstrate that β-eudesmol suppressed the histamine and tryptase releases from the PMA plus calcium ionophore A23187-stimulated HMC-1 cells. β-eudesmol inhibits the expression and activity of histidine decarboxylase in the activated HMC-1 cells. In addition, β-eudesmol inhibits the levels of histamine and tryptase released from the compound 48/80-stimulated RPMCs. Furthermore, β-eudesmol decreases the intracellular calcium level in the activated RPMCs. β-eudesmol also decreases the compound 48/80-induced mortality and ear swelling response. β-eudesmol suppresses the serum levels of histamine, IgE, interleukin (IL)-1β, IL-4, IL-5, IL-6, IL-13, and vascular endothelial growth factor (VEGF) under PCA mice as well as PCA reactions. Therefore, the results from this study indicate the potential of β-eudesmol as an anti-allergic drug with respect to its pharmacological properties against mast cell-mediated allergic reactions.