Effect of Hypericum perforatum on marble-burying by mice.

The effect of Hypericum perforatum extract (LI 160) at a dose that exerts an antidepressive-like effect was studied in mice in the marble-burying test. Acute Hypericum perforatum (150, 300 and 500 mg/kg, p.o.) reduced immobility time in the forced swimming test. The number of marbles buried, but not locomotor activity, was reduced by acute treatment with Hypericum perforatum (150 and 300 mg/kg, p.o.). However, this effect was not seen after chronic treatment (21 days) with Hypericum perforatum (300 mg/kg, p.o.). Thus, Hypericum perforatum extract, at antidepressant dose, exerts an acute anxiolytic drug effect on the marble-burying test, which could indicate a potential anti-obsessive effect, although the development of tolerance could be an important drawback. Copyright 2004 John Wiley & Sons, Ltd.