Nutrition Bytes

In Germany extracts of Hypericum perforatum, commonly called St. John's wort, are among the most widely prescribed antidepressants, accounting for over 25% of antidepressant prescriptions. Such use exemplifies the increasing interest surrounding herbal medicines throughout the United States and Europe and an increasing need for research on unregulated alternative therapeutics. This paper reviews recent investigations of receptor binding affinity of extracts of H. perforatum as well as clinical trials and meta-analyses of its efficacy as a herbal antidepressant. Significant receptor affinity has been demonstrated for GABA, benzodiazepine, adenosine, NMDA, serotonin (5HT1) and monoamine oxidase with the latter two most likely implicated in its therapeutic action. Meta-analyses have consistently demonstrated significant therapeutic benefit from H. perforatum extract over placebo in mild, moderate and severe depression. This benefit is not significantly different from benefits derived from tricyclic antidepressants except after 6 weeks when H. perforatum benefits are moderately less. However, reduced side-effects may make H. perforatum extract a preferred treatment over many current antidepressant medications.