The antidepressant activity of Hypericum perforatum L. measured by two experimental methods on mice.

The pharmacological approach to the treatment of depression includes a long-term employment of antidepressants, either in the form of monotherapy or as a combination of several antidepressants with various mechanisms of action. Hypericum perforatum L. (St. John's wort) is the only natural antidepressant. Several constituents of the extract, such as hypericin and hyperforin, seem to be important for this effect. H. perforatum is considered to be an effective alternative to other therapeutic agents in the treatment of mild to moderate depression. The paper describes the investigation of the antidepressant effect of H. perforatum (doses 7, 35 and 70 mg kg(-1) b. m.) on mice using the forced-swimming and tail-suspension methods. As an indicator of the antidepressant effect, it was shown that the immobility time of animals in the forced-swimming and tail-suspension experiments was shorter, i.e. the activity of the animals was higher. With single doses of extract suspension increasing from 7 over 35 to 70 mg kg(-1) the antidepressant effect increased in proportion by 10.1%, 25.8% and 38.6% in the swimming method, and by 12.7%, 16.5% and 24.5% in the tail-suspension method compared to controls. H. perforatum extract displays dose-dependent antidepressant effect at a dose as low as 7 mg kg(-1). Both models have proved to be equally valuable for demonstration of substances with a potential antidepressant effect.