A review of studies in alcohol-preferring rats shows that extracts from St. John's wort, kudzu, and ibogaine, as well as purified compounds from these plants (puerarin, daidzin, daidzein, and ibogaine analogs), dose-dependently reduce alcohol intake after a single dose, with minimal effects on food intake. Puerarin and St. John's wort extract also remain effective with repeated dosing. The compounds appear to work by modulating multiple brain systems involved in drinking, though their exact mechanisms are not fully understood. Whether these compounds become treatments for alcoholism depends on future clinical trials.
The Fawn-Hooded rat (FH/Wjd) is an inbred strain that naturally consumes high amounts of alcohol (over 5 g/kg/day) with a preference above 65%. Unlike selectively bred alcohol-preferring strains, this strain was chosen due to a serotonin platelet abnormality, but breeding experiments showed that the high alcohol intake is unrelated to that serotonin defect. Many compounds tested in these rats reduce alcohol intake, including amperozide, MTEP, ibogaine, St. John's wort, and kudzu extract. However, tolerance can develop to some drugs like opiate antagonists, possibly due to up-regulation of opioid receptors. This tolerance also appears in selectively bred alcohol-preferring rats, raising questions about its role in relapse among people treated with naltrexone. The broad range of effective compounds suggests diverse targets for developing new alcoholism treatments.