[Origin]:Hypericum perforatum Linn.
[Appearance]: Violine crystalline powder
Hypericin is an antiviral found in a common plant, St. John’s wort, a medicinal herb. Unfortunately, there is very little of the chemical in the plant, and laboratory and animal studies suggest that the dose available in common herbal preparations is too small to be effective. People with AIDS or HIV have used these herbal preparations for about two years, with mixed reports but no clear evidence of benefit. [For more background on hypericin, see coverage in AIDS TREATMENT NEWS, especially issues #63 (August 26, 1988), #91 (November 17, 1989), #96 (February 2, 1990), and #117 (December 21, 1990)].
A clinical trial using chemically synthesized hypericin could start as early as May at New York University Medical Center/Bellevue Hospital, the University of Minnesota at Minneapolis, and Boston Beth Israel Hospital. This trial was scheduled to start in the summer or fall of 1990, but was delayed by difficulties in preparing sufficient drug. Enough hypericin is now available.
We received the following summary from Fred Valentine, M. D., the principal investigator:
“The study is designed for HIV-infected individuals with less than 300 CD4 cells (i.e., T-helper count under 300), with or without symptoms, who have not taken any antiretroviral drug for one month prior to starting hypericin. Increasing doses of hypericin will be administered intravenously twice a week to successive groups of individuals to determine the maximum tolerated dose. Plasma viremia, p24, cellular viremia, and change in CD4 T-cells will be measured to determine what doses may be effective. It is important that individuals entering this trial of hypericin do not take AZT, ddI, ddC, or other antiretroviral agents, because these agents might have increased toxicity when taken with hypericin, and because the effects of the drugs would interfere with the ability of the trial to measure the effect of hypericin on viremia, p24, and CD4 cells.” G}&`~r275G
It is important to study this potential treatment because:
* In one animal study, hypericin worked much better than AZT against a mouse retrovirus which is used to screen possible anti-retroviral compounds. (HIV itself could not be used in these tests, because ordinary mice cannot be infected with the human virus.)
* Animals can tolerate large amounts of hypericin with little toxicity. The levels which are expected to be antiviral can easily be reached.
* Hypericin’s mode of action against HIV in the laboratory is entirely different than that of AZT, suggesting that hypericin might provide an important therapeutic alternative, either alone or in combination with AZT.
in whole human blood freshly drawn from HIV-positive patients. Data suggests that it can work in both lymphocytes (e.g. T-helper cells) and monocytes (e.g. macrophages). The test with whole blood is important because it shows activity against the “wild” virus strains found in patients, not only against the strains which have been bred for years in laboratories.
* Laboratory tests have also shown activity against certain other viruses, including herpes and possibly CMV.
* In small doses, hypericin has already been in widespread human use for years, both as an “alternative” HIV treatment, and as an antidepressant in Europe.
* Hypericin should be convenient to take. Animal studies suggest that it can be given orally — and may only need to be taken twice a week to maintain effective blood levels.
There are also disadvantages. Human toxicity of large doses is not known. Possible problems to watch for are
herbal extract, although not necessarily caused by hypericin), and phototoxicity (extreme sensitivity to sunlight or other ultraviolet light, a problem seen in farm animals when they eat large amounts of the plant).
The trial described above plans to test hypericin doses up to 2 mg per kg of body weight (about 150 mg for an average adult), providing that no serious toxicities are seen before that level. By contrast, the herbal tablets most commonly sold in buyers’ clubs contain 250 mg of 0.14 percent hypericin, or 0.35 mg of the drug — hundreds of times smaller than the highest dose planned for the trial. The tablets and other herbal preparations contain many chemicals, and taking very large doses would involve serious risks.
We have heard that it is not very difficult to chemically extract relatively pure hypericin from the St. John’s wort plant; the plant is common in most of the world. At this time, however, we do not know of any source where the chemical is available. (We have not looked for it, because of the risks of trying a new drug; it seemed better to wait for the clinical trial, which will test hypericin with very close monitoring for possible toxicity.)
One factor delaying this drug was the need to develop an improved synthesis procedure which will be suitable for large- scale commercial use. If researchers had used the plant material first, they would have had to repeat animal and human testing after the synthetic version became available. FDA-required animal toxicity testing, done in specialized labs, can cost hundreds of thousands of dollars, creating major barriers to drug development by all but large or well-financed companies.
One problem which no one anticipated is that the synthetic material has not proven as effective as the plant material in antiviral tests in animals (although it is still effective). It is not known why this is so.
Another finding which anyone researching hypericin should know is that animal tests have found that some preparations of the chemical are less orally available than others, for reasons now unknown. If one hypericin extract fails to work, then blood tests could be used to make sure the chemical is being absorbed. A different extraction procedure might work better.
The chemical mode of action of hypericin may involve a singlet oxygen; if so, certain antioxidants might reduce its effectiveness.
What should have been done two years ago, and still should be done now, is to chemically extract enough hypericin from the plant to treat a few people and see whether or not there is a clear, dramatic benefit. If there is, then the resources would be found to make the treatment available quickly, by whatever means is best. On the other hand, if the results of this early efficacy test are negative or unclear, then the development of the drug can proceed on its present course.
This approach, of an early, rapid test for a possible “home run” drug, may be impossible in the current regulatory system. It may happen instead underground.
Hypericin Technical Articles
These articles and abstracts are relevant to the development of hypericin as a possible antiviral. Also see the previous issues of AIDS TREATMENT NEWS cited above.
Barnard DL, Huffman JH, and Wood, SG. Characterization of the anti human cytomegalovirus (HCMV) activity of three anthraquinone compounds [abstract #1093]. 30th Interscience Conference on Antimicrobial Agents and Chemotherapy, Atlanta, October 21-24, 1990.
Chu CK, Schinazi RF, and Nasr M. Anti-HIV-1 activities of anthraquinone derivatives in vitro [abstract #M. C. P. 115]. V International Conference on AIDS, Montreal, June 4-9, 1989.
Cooper WC and James JS. An observational study of the safety and efficacy of hypericin in HIV+ subjects [abstract #2063]. VI International Conference on AIDS, San Francisco, June 21-24, 1990.
Degar S, Lavie G, Levin B, and others. Inhibition of HIV infectivity by hypericin: Evidence for a block in capsid uncoating [abstract #I-16]. HIV Disease: Pathogenesis and Therapy, University of Miami, March 1991.
Kraus GA, Pratt D, Tossberg J, and Carpenter S. Antiretroviral activity of synthetic hypericin and related analogs. Biochemical and Biophysical Research Communications. 1990; volume 172, pages 149-153.
Lavie G, and Meruelo D. Inhibition of retrovirus-induced diseases by two naturally occurring polycyclic aromatic diones hypericin and pseudohypericin [abstract #C. 501]. V International Conference on AIDS, Montreal, June 4-9, 1989.
Lavie G, Valentine F, Levin B, and others. Studies of the mechanisms of action of the antiretroviral agents hypericin and pseudohypericin. Proceedings of the National Academy of Sciences, USA. August 1989; volume 86, pages 5963-5967.
Lavie G, Mazur Y, Lavie D, Levin B, Ittah Y, and Meruelo D. Hypericin as an antiretroviral agent; mode of action and related analogues. Annals of the New York Academy of Sciences. 1990; volume 616, pages 556-562.
Lavie G, Meruelo D, Daub M, and others. Retroviral particle inactivation by organic polycyclic quinones: A novel mechanism of virucidal activity characterized by diminution of virus particle derived reverse transcriptase enzymatic activity [abstract I-27]. HIV Disease: Pathogenesis and Therapy conference, University of Miami, March 1991.
Meruelo D, Lavie G, and Lavie D. Therapeutic Agents with Dramatic Antiretroviral Activity and Little Toxicity at Effective Doses: Aromatic Polycyclic Diones Hypericin and Pseudohypericin. Proceedings of the National Academy of Sciences, USA. July 1988; volume 85, pages 5230-5234.
Meruelo D, Degar S, Levin B, Lavie D, Mazur Y, and Lavie G. Inactivation of retroviral particles by hypericin: Possible role of oxidative reactions in the antiretroviral activity [abstract I-29]. HIV Disease: Pathogenesis and Therapy, University of Miami, March 1991.
Schinazi RF, Chu CK, Babu JR, and others. Anthraquinones as a new class of antiviral agents against human immunodeficiency virus. Antiviral Research. 1990; volume 13, pages 265-272.
Takahashi I, Nakanishi S, Kobayashi E, Nakano H, Suzuki K, and Tamaoki T. Hypericin and pseudohypericin specifically inhibit protein kinase C: possible relation to their antiretroviral activity. Biochemical and Biophysical Research Communications. December 29, 1989; volume 165, number 3, pages 1207-1212.
Tang J, Colacino JM, Larsen SH, and Spitzer W. Virucidal activity of hypericin against enveloped and non- enveloped DNA and RNA viruses. Antiviral Research. 1990; volume 13, pages 313-326.
Valentine F, Meruelo D, Itri V, and Lavie G. yMHypericin: efficacy of a new agent against HIV in vitro [abstract #M. C. P. 18]. V International Conference on DS, Montreal, June 4-9, 1989.
Valentine FT. Hypericin: A hexahydroxyl, dimethyl- naphthodianthrone with activity against HIV in vitro and against murine retroviruses in vivo [oral presentation, published abstract]. HIV Disease: Pathogenesis and Therapy, University of Miami, March 1991.
Weiner DB, Lavie G, Williams WV, Lavie D, Greene MI, and Meruelo D. Hypericin mediates anti-HIV effects in vitro [abstract #C. 608]. V International Conference on AIDS, Montreal, June 4-9.
Wood S, Huffman J, Weber N, and others. Antiviral activity of naturally occurring anthraquinones and anthraquinone derivatives. Planta Medica; Journal of Medicinal Plant Research. 1990; volume 56, number 6, pages 651-652.
Hypericin is a red-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 ß-hydroxylase, leading to increased dopamine levels, although thus possibly decreasing norepinephrine and epinephrine.
The large chromophore system in the molecule means that it can cause photosensitivity when ingested beyond threshold amounts. Because hypericin accumulates preferentially on cancerous tissues, it is also used as an indicator of cancerous cells. In addition, hypericin is under research as an agent in photodynamic therapy, whereby a biochemical is absorbed by an organism to be later activated with spectrum-specific light from specialized lamps or laser sources, for therapeutic purposes.