Anti-allergic effects of scoparone on mast cell-mediated allergy model.

Scoparone is known to have a wide range of pharmacological properties in vitro. However, the roles of scoparone in immediate-type allergic reactions have not yet been investigated. In this study, we demonstrated that scoparone attenuated IgE-mediated allergic response in mast cells. Oral administration of scoparone inhibited passive cutaneous anaphylaxis in rats. Presence of scoparone dose-dependently decreased histamine release from rat peritoneal mast cells (RPMC) stimulated by anti-dinitrophenyl IgE. Moreover, scoparone reduced the expression and secretion of pro-inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-6 in RPMC. Pretreatment with scoparone inhibited the calcium uptake and p38 mitogen-activated protein kinase (MAPK) activity. Furthermore, scoparone blocked translocation of nuclear factor-kappa B (NF-kappaB) p65 subunit by suppressing IkappaBalpha phosphorylation in RPMC. Reduced calcium uptake as well as the suppressed activity of p38 MAPK and NF-kappaB might be involved in the inhibitory effect of scoparone on the secretory response. Our findings suggest that scoparone may serve as an effective therapeutic agent for allergic diseases.