Hypericin is a re-coloured anthraquinone-derivative, which is together with Hyperforin one of the principal active constituents of Hypericum (Saint John's wort). Hypericin is believed to act as an antibiotic and non-specific kinase inhibitor. Hypericin may inhibit the action of the enzyme dopamine β-hydroxylase, leading to increased dopamine levels, although thus possibly decreasing norepinephrine and epinephrine.