Effect of Saiboku-to, a blended Chinese traditional medicine, on Type I hypersensitivity reactions, particularly on experimentally-caused asthma

Abstract

Effect of Saiboku-to, which has been used for the therapy of bronchial asthma, on Type I hypersensitivity reactions was investigated. Forty eight-hr homologous PCA and antigen-induced histamine release in peritoneal cavities of rats passively sensitized with anti-DNP-As . IgE serum tended to be inhibited by the oral administration of Saiboku-to. On the other hand, 7-day homologous PCA in guinea pigs mediated by anti-BPO-BGG . IgE serum was significantly inhibited with 200 and 500 mg/kg of Saiboku-to given orally 2 hr prior to challenge. In experimentally caused asthma in guinea pigs, 200 mg/kg of Saiboku-to dramatically inhibited decreases in the rate and volume of respiration, and 500 mg/kg of the drug inhibited even an increase in the ratio of expiration time to inspiration time. The Schultz-Dale reaction in guinea pig tracheal muscle was significantly inhibited by the pretreatment with 10(-4) g/ml of Saiboku-to. The antigen-induced histamine release from sensitized guinea pig lung tissue was inhibited by 10(-6) to 10(-4) g/ml of Saiboku-to in a dose-dependent fashion, though the release of SRS-A was not affected. Saiboku-to did not show an antagonistic effect on allergic mediator-induced contraction in guinea pig ileum. From these results, it is considered that Saiboku-to shows an inhibitory activity on the Type I hypersensitivity reaction through the suppression of histamine release.