Hypericin–the facts about a controversial agent.

Kubin A, Wierrani F, Burner U, Alth G, Grünberger W.

Hypericin is a naturally occurring substance found in the common St.
John’s Wort (Hypericum species) and can also be synthesized from the
anthraquinone derivative emodin. As the main component of Hypericum perforatum,
it has traditionally been used throughout the history of folk medicine. In the
last three decades, hypericin has also become the subject of intensive
biochemical research and is proving to be a multifunctional agent in drug and
medicinal applications. Recent studies report antidepressive, antineoplastic,
antitumor and antiviral (human immunodeficiency and hepatitis C virus)
activities of hypericin; intriguing information even if confirmation of data is
incomplete and mechanisms of these activities still remain largely unexplained.
In other contemporary studies, screening hypericin for inhibitory effects on
various pharmaceutically important enzymes such as MAO (monoaminoxidase), PKC
(protein kinase C), dopamine-beta-hydroxylase, reverse transcriptase,
telomerase and CYP (cytochrome P450), has yielded results supporting
therapeutic potential. Research of hypericin and its effect on GABA-activated
(gamma amino butyric acid) currents and NMDA (N-methyl-D-aspartat) receptors
also indicate the therapeutic potential of this substance whereby new insights
in stroke research (apoplexy) are expected. Also in the relatively newly
established fields of medical photochemistry and photobiology, intensive
research reveals hypericin to be a promising novel therapeutic and diagnostic
agent in treatment and detection of cancer (photodynamic activation of free
radical production). Hypericin is not new to the research community, but it is
achieving a new and promising status as an effective agent in medical diagnostic
and therapeutic applications. New, although controversial data, over the recent
years dictate further research, re-evaluation and discussion of this substance.
Our up-to-date summary of hypericin, its activities and potentials, is aimed to
contribute to this process.