Effects of purified puerarin on voluntary alcohol intake and alcohol withdrawal symptoms in P rats receiving free access to water and alcohol

Alcohol preferring (P) rats, given "free choice" of water, exhibited daily intake of 60-75 g of water/kg of body weight. When given "free choice" of water and 15% ethanol, P rats consumed 7-13 g of alcohol/kg. Their water intake decreased proportionally to the alcohol intake, but total fluid intake did not differ significantly. Alcohol withdrawal after 50 days of alcohol drinking caused withdrawal symptoms such as hypersensitivity, poor coordination, and tremors. A daily 50 mg/kg dose of puerarin (PU) caused approximately 50% suppression in alcohol intake, but did not affect body weight and food and total fluid intake in P rats receiving "free choice" of water and 15% ethanol. Alcohol ingestion gradually returned to the control level despite consistent PU intake. However, alcohol intake following alcohol withdrawal was suppressed in PU-fed P rats. PU suppressed the severity of alcohol withdrawal symptoms. Thus, withdrawal symptoms do not occur in PU-fed rats even though their alcohol ingestion is comparable to that in control P rats. Brain, plasma, and liver samples were analyzed for the presence of kudzu root isoflavones, which are mostly PU (>90% of total isoflavones) and a trace amount of daidzin. Liver samples obtained from PU-fed P rats contained 20-30 microg/g of PU. An important observation was that plasma or brain samples obtained from PU-fed or alcohol + PU-fed rats did not contain PU. This study indicated that PU feeding transiently suppressed alcohol intake and abolished withdrawal symptoms at a time when alcohol intake had returned to the control level. The absence of PU in plasma and brain indicates the possibility that some nonspecific mechanism may be involved in the anti-alcoholism effects of PU in P rats.