Pharmacological effects of urinary products obtained after treatment with Saiboku-To, a herbal medicine for bronchial asthma, on type IV allergic reaction

To define the anti-allergic components in Saiboku-To, a herbal medicine for bronchial asthma, we examined the effects of 11 compounds found in post-ad ministrative urine of Saiboku-To on concanavalin A-induced human lymphocyte blastogenesis in vitro and picryl chloride (PC)-induced mouse ear swelling in vivo. The urinary products of Saiboku-To were flavonoids and lignans de rived from the constitutional herbs and their hydrogenated metabolites. Med icarpin derived from Glycyrrhizo glabra, magnolol and 8,9-dihydroxydihydrom agnolol from Magnolia officinalis, baicalein, wogonin and oroxylin A from S uctellario baicalensis inhibited lymphocyte blastogenesis in dose-dependent fashion with IC50 values ranging from 3.0 to 7.7 mug/mL, which corresponde d to 20 - 100 times that of prednisolone IC50 (0.08 mug/mL). Davidigenin, d ihydrowogonin and dihydrooroxylin A, which are hydrogenated metabolites of liquiritigenin, wogonin and oroxylin A, respectively, had no or little effe cts on lymphocyte blastogenesis. Oral administration of Saiboku-To, medicar pin, baicalein, magnolol and baicalin (100 mg/kg), inhibited PC-induced ear swelling significantly by 23.5, 40.1, 30.5, 23.6 and 20.9%, respectively, though the effects were weaker than that of 5 mg/kg of prednisolone (52.9%) . The results suggested that flavonoids and lignans tested in the present s tudy were implicated in anti-asthmatic effect of Saiboku-To through suppres sion of type IV allergic reaction.