St. John’s Wort
St. John’s wort (Hypericum perforatum) is a
flowering plant that has been used as a medicinal
herb for centuries (Figure 1). It is particularly
popular in parts of Europe where it has attained
regulatory approval for use as an antidepressant
– in Germany for example. Despite its widespread
use, lingering controversy persists regarding its
effectiveness. !e most appropriate dosage is not
well-characterized, nor is its mechanism of action
entirely clear, in part because the question of which
of its constituents are responsible for its moodenhancing
effect is still largely unanswered. !e
plant contains a number of constituents thought
to be pharmacologically active, including hypericin
and hyperforin.45 Recent research suggests that
Hypericum extract exhibits a “broad spectrum of
action,” reportedly inhibiting the reuptake of as
many as five neurotransmitters (serotonin, dopamine,
norepinephrine, L-glutamate, and gammaaminobutyric
acid [GABA]).46 A new species of
Hypericum (Hypericum enshiense) identified in
China has been reported to also have potential
antidepressant activity based on animal behavioral
models; however, there are currently no clinical
data.47