Hypericin Set type / Edit
«Hypericin is a naphthodianthrone, an anthraquinonederivative which, together with hyperforin, is one of the principal active constituents of Hypericum (Saint John's wort). Hypericin is believed to act as an antibiotic, antiviral and non-specific kinaseinhibitor. Hypericin may inhibit the action of the enzyme dopamine β-hydroxylase, leading to increased dopamine levels, although thus possibly decreasing norepinephrine and epinephrine.
It was initially believed[according to whom?] that the anti-depressant pharmacological activity of hypericin was due to inhibition of monoamine oxidase enzyme. The crude extract of Hypericum is a weak inhibitor of MAO-A and MAO-B. Isolated hypericin does not display this activity, but does have some affinity for NMDA receptors. This points in the direction that other constituents are responsible for the MAOI effect. The current belief is that the mechanism of antidepressant activity is due to the inhibition of reuptake of certain neurotransmitters.