Effect of gomisin A (TJN-101), a lignan compound isolated from Schisandra fruits, on liver function in rats

TJN-101 [+)-(6S, 7S, R-biar)-5,6,7,8-tetrahydro-1,2,3,12-tetramethoxy- 6,7-dimethyl-10,11-methylenedioxy-6-dibenzo [a, c] cyclooctenol) is one of the lignan compounds isolated from Schisandra fruits. When TJN-101 was administered orally at the doses of 3-100 mg/kg/day for 4 days, bile secretion, hepatic excretion of dye or hepatic hemodynamics 24 hr after the last dose was investigated in comparison with the phenobarbital (100 mg/kg/day)-treated group. Bile flow was dose-dependently increased; in contrast, biliary concentration of bile acids was decreased in TJN-101 (30 and 100 mg/kg/day)-treated groups. Similar changes were also observed in the phenobarbital-treated group. These results suggested that the enhancement of bile secretion caused by TJN-101 or phenobarbital was due to an increase of a bile acid-independent fraction. In the bromosulfophthalein (BSP) clearance test for liver function, both TJN-101 (30 and 100 mg/kg/day) and phenobarbital accelerated the disappearance from the blood and biliary excretion of BSP. Hepatic hemodynamics was examined by the hydrogen clearance method and measurement of liver wet and dry weight. Liver blood flow tended to increase in the TJN-101 (10-100 mg/kg/day) or phenobarbital-treated group. On the other hand, TJN-101 (3-100 mg/kg/day) or phenobarbital hardly altered the water content of the liver. These results suggested that the liver enlargement caused by both compounds was not accompanied with hepatic edema and that the enhancement of bile secretion or hepatic excretion of BSP might be related to an increase of liver blood flow.