Effects of saiboku-to on dual-phase bronchoconstriction in asthmatic guinea pigs

In recent years, bronchial asthma has come to be regarded pathologically as a chronic inflammatory disease of the respiratory tract. Inhalational steroids and antiinflammatory drugs are recognized as being effective against bronchial asthma. In this study, the effects of Saiboku-to, a Chinese herbal (Kampo) formulation, were investigated on asthmatic guinea pigs sensitized to ovalbumin (OA). Following 7-day administration of Saiboku-to (500 micrograms/kg), the late asthmatic response (LAR) to an antigen challenge was found to be inhibited. The number of eosinophils in fluid obtained by bronchoalveolar lavage (BAL) 4 h after antigen challenge was decreased while the infiltration of eosinophils and T-lymphocytes into the lung parenchyma was inhibited. These findings suggest that Saiboku-to has the potential to become a useful drug in the treatment of bronchial asthma.