Efficacy in behavioural models of antidepressant activity.

Extracts of Hypericum perforatum have been tested in experimental models of depression in rodents and their efficacy in these models has been demonstrated after acute, subacute, or repeated administration. In order to identify the component responsible for this activity, extracts with different proportions of hyperforin, currently the most likely active antidepressant principle, have been tested. Different groups reported a correlation between efficacy in these models and the hyperforin content of the extract. Moreover, purified hyperforin is active at doses significantly lower than those necessary for observing an activity when the extract is used. In conclusion, we now have convincing experimental evidence of the efficacy of Hypericum perforatum extract in models of depression.