K.M. KO, P.K. YICK, TW. CHIU, T.Y. HUI, CHRISTOPHER H.K. CHENG, Y.C. KONG
In the present study, a drastic impairment in hepatic antioxidant status was observed in rats 24 h following oral administration of carbon tetrachloride as indicated by increases in the sensitivity of hepatic tissue homogenates to glutathione depletion and formation of thiobarbituric acid reactive substances following in vitro oxidative challenge, as well as decreases in tissue glutathione content and activities of glutathione reductase and Cu, Zn-superoxide dismutase. These hepatic alternations were accompanied by an increase in plasma alanine aminotransferase activities, Hepatoprotection afforded by pretreating carbon tetrachloride-intoxicated rats with a single dose of vitamin E (400 mg/kg, s.c.) or multiple doses of herbal exracts (100 mg/rat/day, p.o.) was evidenced by the significant reversal of hepatic antioxidant capacity and plasma alanine aminotransferase activity. While the depressed antioxidant enzyme activities were only marginally increased by vitamin E pretreatment, the herbal extract pretreatment significantly restored the activity of these enzymes. The measurement of hepatic antioxidant status in carbon tetrachloride intoxicated rats may provide a useful in vivo model for screening herbal extracts with antioxidant activities.