Inhibition of immediate-type allergic reactions by the aqueous extract of Salvia plebeia.

The effect of aqueous extract of Salvia plebeia R. Brown (Labiatae) (SPAE) on the mast cell mediated immediate-type allergic reactions in rats was studied. SPAE (0.05 to 1 g/kg) inhibited systemic allergic reaction induced by compound 48/80. SPAE (0.001 and 1 g/kg) dose-dependently inhibited passive cutaneous anaphylaxis (PCA) when intraperitoneally, intraveneously or orally administered. When SPAE was pretreated at the same concentrations with systemic allergic reaction test, the plasma histamine levels were reduced in a dose-dependent manner. SPAE (0.001 to 1 mg/mL) dose-dependently inhibited the histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. The level of cyclic AMP in RPMC, when SPAE (0.1 and 1 mg/mL) was added, significantly increased compared with that of basal cells. Moreover, SPAE (0.01 to 1 mg/mL) had a significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-alpha (TNF-alpha) production. These results indicate that SPAE may possess strong antiallergic activity and suggest that differences in bioavailability may cause differential activity following different administration routes.