Effects of saikosaponins on hepatic damage induced by halothane and hypoxia in phenobarbital-pretreated rats.

The effects of saikosaponins-a.-b1,-b2,-c, and-d on hepatic damage induced by halothane and hypoxia were investigated in the rat. Inhalation of halothane under a hypoxic condition significantly increased serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels in rats pretreated with phenobarbital compared with rats pretreated without phenobarbital. Pretreatment with saikosaponin (especially-a and-d) and with phenobarbital suppressed the increase in serum GOT and GPT levels in comparison with the rats treated with phenobarbital, halothane, and hypoxia. Histological observation also confirmed that pretreatment with saikosaponin had a protective effect against liver cell damage caused by halothane and hypoxia. Saikosaponins-a and-d, the most effective saikosaponins against hepatic damage, inhibited the increases in cytochrome P450 and NADPH-cytochromec reductase activity which are induced by phenobarbital treatment. Therefore, it is suggested that the cytoprotective effect of saikosaponin against halothane-induced hepatitis under hypoxia is caused by inhibition of phenobarbital stimulation of the enzyme system for hepatic drug metabolism.