Neuroendocrine evidence for dopaminergic actions of hypericum extract (LI 160) in healthy volunteers

Background: We studied the effect of a single dose of a formulation of a methanolic extract of Hypericum perforatum (HP), also known as St. John's wort, on plasma concentrations of growth hormone (GN), prolactin (PRL), and cortisol (CORT) in 12 healthy male volunteers. Methods: Subjects received 9 tablets of the finished product Jarsin(R)300 and placebo in a double-blind balanced-order cross-over design. Results: Following HP relative to placebo, there was a significant increase in plasma GH and a significant decrease in plasma PRL. Plasma CORT levels were unchanged. Conclusions: Taken together with data from animal experimental studies, the findings suggest that this dose of HP may increase some aspects of brain dopamine function in humans. Biol Psychiatry 1999;46:581-584 (C) 1999 Society of Biological Psychiatry.