Antiallergic action of magnolia officinalis on immediate hypersensitivity reaction

We studied the effect of aqueous extract of Magnolia officinalis bark (Magn oliaceae) (MOAE) on the immediate hypersensitivity reaction. MOAE (0.01 to 1 g/kg) dose-dependently inhibited compound 48/80 induced systemic anaphyla xis in rats. MOAE (0.1 and 1 g/kg) also significantly inhibited local immun oglobulin E (IgE)-mediated passive cutaneous anaphylactic reaction. When MO AE was pretreated at concentrations ranging from 0.01 to 1 g/kg, the levels of plasma histamine were reduced in a dose-dependent manner. MOAE (0.001 t o 1 mg/ml) dose-dependently inhibited the histamine release from rat perito neal mast cells (RPMC) activated by compound 48/80 or anti-dinitrophenyl (D NP) IgE. The level of cyclic AMP (cAMP) in RPMC, when MOAE was added, signi ficantly increased compared with that of the normal control. Moreover, MOAE (0.01 to 1 mg/ml) had a significant inhibitory effect on anti-DNP IgE-indu ced tumor necrosis factor-alpha production from RPMC. These results indicat e that MOAE inhibits immediate hypersensitivity reaction in vivo and in vit ro.