Effect of antenatal exposure to Saint John’s wort (Hypericum ) on neurobehavior of developing mice

Objective: We conducted, in a randomized, placebo-controlled manner, behavioral testing on mice offspring exposed antenatally to the herbal antidepressant Saint John’s wort (Hypericum ). Study Design: A daily dose of Saint John’s wort (0.75 mg/g of food consumed), equivalent to that in human beings according to body surface, was chosen because it has been shown to cause an antidepressant effect in adult mice. CD-1 mice were randomly assigned to consume either Saint John’s wort (n = 45) or a placebo (n = 45) for 2 weeks before conception and throughout gestation. Behavioral testing consisted of early developmental tasks of geotaxis, separation vocalization, and homing, followed by motor, anxiety, and depression assessments into adulthood. Results: Birth weights of male offspring were less in the Saint John’s wort group than in the placebo group (1.68 vs 1.75 g; P