Hypericin and pseudohypericin, pigment molecules extracted from St. Johns Wort (Hypericum perforatum) and related species, have been shown to have dramatic antiviral activity, especially in the presence of light. Hypericin is considerably more active than pseudohypericin or the various other compounds found in all St. Johns Wort extracts.

Hypericin only inhibits viruses having lipid envelopes — it seems to disrupt various stages of viral replication, including assembly, budding, shedding and possibly protein synthesis, all of which depend on the integrity of the viral envelope. Viruses with lipid envelopes include HSV-1 and HSV-2 (the herpes simplex viruses), CMV (cytomegalovirus), HIV (the AIDS virus), influenza A virus, EBV (Epstein-Barr virus), FV (Friend Leukemia Virus), and other less well-known viruses.

Light is required for the antiviral activity of hypericin. The compound absorbs photons of light and applies the energy to oxygen atoms to form “singlet” oxygen, a free radical. Presumably the singlet oxygen then reacts with nearby cellular membranes or viral components, producing damage that prevents them from being assembled into complete virus particles. Experiments have shown that fluorescent light contains the wavelengths needed to photoactivate hypericin.

In experiments using Friend Leukemia Virus, hypericin given in a single dose of low concentration was effective without being cytotoxic. Even when it was administered after viral infection had already started, it still inhibited the onset of disease.

Liver function should be tested periodically in persons taking hypericin. Also, extreme photo-sensitivity has been observed in a few cases of people taking high doses (in excess of 10 mg per day).

This article is a synopsis of an article by A.Y. Oubre, which appears in its original form at: http://www.lifelinknet.com/siteResources/ArchivePages/Hypericin-Active.asp