Anti-allergic effect of aqueous extract of Stachys riederi var. japonica Miq. in vivo and in vitro

The effect of aqueous extract of Stachys riederi var. japonica Miq. (Labiatae) (SRAE) on the immediate-type allergic reactions was investigated. SRAE was found to exhibit a inhibitory activity on the compound 48/80-induced systemic anaphylaxis in mice. SRAE inhibited the plasma histamine release induced by compound 48/80 in mice. In addition, SRAE also inhibited the passive cutaneous anaphylaxis reaction induced by IgE/anti-IgE in mice. The effect of SRAE on the histamine release from rat peritoneal mast cells (RPMC) was studied. SRAE inhibited the histamine release induced by compound 48/80 in RPMC. To clarify the mechanism of these inhibiting reactions, we investigated the effects of SRAE on cyclic AMP (cAMP). The level of cAMP in human leukemia cell line, HMC-1, when SRAE (1 mg/ml) was added, significantly increased compared with that of basal cells. These results indicate that SRAE may be beneficial in the treatment of immediate-type allergic reaction.