Attenuation of alcohol intake by extract of Hypericum perforatum (St John's Wort) in two different strains of alcohol-preferring rats

Extract of the common plant Hypericum perforatum L. (St John's Wort, SJW) h as been used successfully for the treatment of mild to moderate depression since ancient times and has recently been studied clinically. Depression an d alcoholism have some neurochemical similarities, such as low brain seroto nin activities. Thus, we hypothesized that SJW extract, which contains 0.22 % hypericin and 4.05% hyperforin, also may be effective in suppressing alco hol intake. To test this hypothesis, the effects of SJW extract on voluntar y alcohol intake were studied in two different genetic animal models of hum an alcoholism: fawn-hooded (FH) and high-alcohol drinking (HAD) rats. FH an d HAD rats received a single oral administration (5 ml/kg) of either vehicl e or one of the five doses (100, 200, 400, 600, and 800 mg/kg) of SJW extra ct. The oral administration of SJW extract significantly (P < 0.0001) reduc ed alcohol intake in both FH and HAD rats. In a third study, FH rats did no t develop tolerance to the suppressant effects of SJW on alcohol intake and preference following oral administration of (400 mg/kg) of the extract for 15 consecutive days. These promising findings suggest that SJW extract sho uld be evaluated clinically as a potential therapeutic agent in the treatme nt of alcoholism.