Scutellaria baicalensis Inhibits Mast Cell-Mediated Anaphylactic Reactions

Abstract

Mast cells play a critical role in the effector phase of immediate hypersensitivity and allergic diseases. Scutellaria baicalensis is a widely used herb in traditional oriental medicine with anticancer, antiviral, antibacterial and anti-inflammatory properties. However, the roles of Scutellaria baicalensis in mast cell-mediated anaphylactic reactions have not fully been investigated. In this study, we examined the influences of the methanol extract of Scutellaria baicalensis (MESB) on compound 48/80- or anti-dinitrophenyl (DNP) IgE-induced anaphylaxis-like response in vivo. To further prove these in vivo results, the inhibitory effect of MESB on mast cell activation was evaluated, focusing on the histamine release from rat peritoneal mast cells (RPMC). MESB inhibited compound 48/80-induced systemic anaphylaxis-like reaction, plasma histamine release and ear swelling response in mice. MESB also attenuated passive systemic and cutaneous anaphylaxis evoked by anti-DNP IgE. In in vitro experiments, MESB dose-dependently reduced histamine release from RPMC activated by compound 48/80 or anti-DNP IgE. Moreover, compound 48/80-elicited calcium uptake was suppressed in a concentration-dependent manner of MESB. Furthermore, MESB transiently increased the level of intracellular cAMP. From these results, it is suggested that MESB possesses effective anti-anaphylactic activity.