Effects of Byakushi and Ogon on the hepatic drug metabolizing enzymes in rats

The effect of single or daily oral administration of hot water extracts (HWE) from Byakushi or Ogon on rat hepatic drug-metabolizing enzymes were investigated in vivo. Enzymes were measured for 3 to 72 hr after single oral administration of HWE at the dose of 1.0 g/kg or 5.0 g/kg. Administration of 1.0 g/kg of Byakushi and 5.0 g/kg of Ogon inhibited aniline hydroxylase activity, while 5.0 g/kg of Byakushi inhibited it in the early phase, but increased it in the late phase. Byakushi inhibited aminopyrine N-demethylase activity, while 5.0 g/kg of Ogon increased it. Byakushi and Ogon decreased the amount of cytochrome P-450. Byakushi and Ogon increased the amount of cytochrome b5. Byakushi increased cytochrome c reductase activity 3 hr after administration and decreased it 6 and 12 hr after administration. In contrast, 1.0 g/kg of Ogon decreased cytochrome c reductase activity, and 5.0 g/kg increased it 6 hr after administration and decreased it 12 hr after administration. At 24 hr after the last administration to animals treated with a regimen of once a day administration of the HWE (0.1 or 1.0 g/kg) of Byakushi or Ogon for 14 days, the enzymes were measured. Byakushi decreased aminopyrine N-demethylase activity, the amount of cytochrome P-450, and cytochrome c reductase activity. Ogon decreased cytochrome c reductase activity. Byakushi altered the composition of cytochrome P-450 isozyme after daily administration.