Effect of Rehmannia glutinosa on immediate type allergic reaction.

We investigated the effect of aqueous extract of Rehmannia glutinosa steamed root (RGAE) on the allergic reactions in vivo and in vitro. RGAE dose-dependently inhibited systemic allergic reaction induced by compound 48/80. When RGAE was pre-treated at the same concentrations with systemic allergic reaction test, the plasma histamine levels were reduced in a dose-dependent manner. RGAE dose-dependently inhibited skin allergic reaction activated by anti-dinitrophenyl (DNP) IgE. RGAE also dose-dependently inhibited the histamine release from the rat peritoneal mast cells (RPMC) by compound 48/80 or anti-DNP IgE. Moreover, RGAE had significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-alpha production of RPMC. These results indicate that RGAE may be beneficial in the regulation of immediate type allergic reaction.