DAIDZIN, AN ANTIOXIDANT ISOFLAVONOID, DECREASES BLOOD-ALCOHOL LEVELS AND SHORTENS SLEEP TIME INDUCED BY ETHANOL INTOXICATION

The extract from an edible vine, Pueraria lebata, has been reported to be efficacious in lessening alcohol intoxication. In this study, we h ave tested the efficacy of one of the major components, diadzin, from this plant extract. When ethanol (40% solution, 3 g/kg body weight) wa s given to fasted rats intragastrically, blood alcohol concentration ( BAC) peaked at 30 min after alcohol ingestion and reached 1.77 +/- 0.1 4 mg/ml (mean values +/- SD, n = 6). If daidzin (30 mg/kg) was mixed w ith the ethanol solution and given to animals intragastrically, BAC wa s found to peak at 90 min after alcohol ingestion and reached only 1.2 0 +/- 0.30 mg/ml (n = 6) (p < 0.05 vs. controls). The ability of daidz in to delay and decrease peak BAC level after ethanol ingestion was al so observed in fed animals. In both fasted and fed rats given alcohol without daidzin, BAC quickly declined after reaching its peak at 30 mi n. By contrast, BAC levels receded more slowly if daidzin was also fed to the animals. Daidzin showed a chronic effect. Rats fed daidzin for 7 days before ethanol challenge, but not on the day of challenge, als o produced lower and later peak BAC levels. Interestingly, daidzin, wh ether fed to rats only once or chronically for 7 days, did not signifi cantly alter activities of either alcohol dehydrogenase or mitochondri al aldehyde dehydrogenase in the liver. Further experiments demonstrat ed that daidzin shortened sleep time for rats receiving ethanol intrag astrically (7 g/ kg) but not intraperitoneally (2 g/kg). To test wheth er daidzin delayed stomach-emptying, [C-14]polyethylene glycol was mix ed with ethanol and fed to rats. It was found that, 30 min after intra gastric feeding, more ethanol and [C-14]polyethylene glycol remained i n the stomach if rats were also given daidzin. Because daidzin is an i soflavonoid glucoside that possesses strong antioxidant activity, two other antioxidants (i.e., vitamin E and thioctic acid) were tested. Si milar to daidzin, these two antioxidants also delayed and suppressed p eak BAC, as well as shortened sleep time induced by alcohol ingestion. We conclude that: (1) daidzin is effective in countering alcohol into xication; (2) suppression of BAC by daidzin is due mainly to delay of stomach-emptying, but not to accelerated clearance of ethanol in circu lation by liver enzymes; and (3) the effect of daidzin may in part be due to its antioxidant activity.