Synergistic effects of inchin‐ko‐to (Yin‐Chen‐Hao‐Tang) and ursodeoxycholic acid on cholestasis caused by α‐naphthyl isothiocyanate

The effects of the combination of Inchin‐ko‐to, a kampo formulation, and ursodeoxycholic acid on experimental cholestasis were investigated. When administered intraduodenally at noneffective doses of these drugs to rats with intrahepatic cholestasis caused by α‐naphthyl isothiocyanate, the bile flow returned to a near‐normal level and the serum bile acid profile was improved. Among the major components of the kampo formula, Artemisiae capillaris Flos contributed to the change in the bile flow, and Gardeniae Fructus contributed to the improved serum bile acid profile, because ursodeoxycholic acid increased and cholic acid decreased. The results show that urosdeoxycholic acid and Inchin‐ko‐to synergistically improved experimental cholestasis and that this effect occurred because of different functions of the components of Inchin‐ko‐to.