St. John's Wort Collection Mined for Its Medicinal Value

A unique collection of St. John’s wort (Hypericum) curated by Agricultural Research Service (ARS) scientists in Ames, Iowa, is providing university collaborators with genetically diverse, well-documented sources of this herb to use in studies examining its medicinal potential.

In collaboration with Mark Widrlechner, a horticulturist with the ARS crop genebank at the North Central Regional Plant Introduction Station in Ames, scientists from the Center for Research on Botanical Dietary Supplements (CRBDS) are screening 180 germplasm accessions of St. John’s wort for biologically active compounds. Some may be worth evaluating further in clinical trials for their potential to combat viral infections, reduce inflammation or improve digestive health.

Established in 1948, the ARS Ames crop genebank curates more than 50,000 accessions of ornamental plants, maize, oilseeds, vegetables and other crops, and provides them to researchers for many applications. Accessions with medicinal or nutraceutical value include Echinacea (purple coneflower), Hypericum, Prunella (self-heal) and Actaea racemosa (black cohosh). ARS horticulturist Luping Qu curates the collection and Widrlechner coordinates its use for research at CRBDS, one of six Botanical Research Centers funded by the National Institutes of Health from 2005-2010.

The Hypericum collection at Ames was started in the 1990s and today encompasses about 60 species collected from around the world. This diversity has enabled investigations of genetic, environmental and developmental factors affecting the quantity and quality of bioactive compounds, as well as their modes of action.

Of particular interest is how these compounds interact, and whether those interactions are critical to human health benefits. In a recent issue of Pharmaceutical Biology, researchers noted that combinations of four compounds from St. John’s wort (amentoflavone, chlorogenic acid, pseudohypericin and quercetin) were more effective at reducing inflammation in mouse macrophage assays than when each was used alone.

Widrlechner’s collaborators include Diane Birt, Kimberly Hammer, Matthew Hillwig, Jingqiang Wei, George Kraus, Patricia Murphy and Eve Wurtele at Iowa State University; Jeffrey Neighbors, David Wiemer, Wendy Maury and Jason Price at the University of Iowa; and Joe-Ann McCoy, formerly with ARS.

ScienceDaily (Mar. 30, 2010)

» For a more detailed discussion of Extracts of St. John’s wort  – and the medical studies that support its use – see the article on our website at:

Hypericin: the active ingredient in Saint John's Wort

by A.Y. Oubre

Hypericin, a photochemical extracted from St. Johns Wort (Hypericum perforatum) and related species, has been shown to have potent, broad spectrum antimicrobial activity. This compound is an aromatic polycyclic anthrone, a class of colored or pigmented chemical substances which have photosensitizing activity. In both in vitro (laboratory) and in vivo (animal) studies, low, non-toxic doses of hypericin significantly inhibited the replication of several viruses, including HIV, influenza A, cytomegalovirus (CMV), Herpes simplex 1 and 2 (HSV-1 and HSV-2), and Epstein-Barr virus (EBV). Hypericin and its chemical relative, pseudohypericin, produce antiviral activity through a different mechanism of action than do AZT and other nucleoside antiviral agents. Hypericin does not appear to directly alter the activity of reverse transcriptase although it does block the formation of HIV synctium. Recent findings have shown that the antiretroviral action of this compound disrupts uncoating of the lipid envelope of both DNA and RNA viruses, thus preventing infected cells from releasing HIV copies. Theoretically, hypericin and AZT, in combination, may have synergistic antiviral effects against HIV. On the other hand, hypericin actually may increase the toxicity of antiretroviral nucleosides such as AZT, ddI, or ddC.

Traditionally, extracts of St. Johns Wort (which contain hypericin) have been used as an antidepressant, possibly by acting as a MAO inhibitor. The psychotropic effects attributed to hypericin in St. Johns Wort extract suggest that the pigment compound can cross the blood brain barrier (possibly treating neuropsychological symptoms such as dementia). Laboratory investigations indicate that hypericin may be beneficial as an HIV therapy. However, its administration should be carefully monitored by a physician. The levels of hypericin found in most commercially available extracts of St. Johns Wort generally are not sufficient to be therapeutically effective against viral infections.

Liver function should be tested periodically in persons taking hypericin. Also, extreme photosensitivity has been observed in a few cases of people taking this high doses (in excess of 10 mg per day) of this compound. Finally, there is a very small possibility that adverse reactions could occur on occasion between hypericin and other foods or drugs which interfere with MAO inhibitors.

Active principles in St. Johns Wort

The quantity and quality of active principles in Hypericin species vary according to geographical locale, climate, time of day, and time of year. St. Johns Wort contains dianthrone derivatives, mainly in the form of hypericin and pseudo-hypericin as well as flavonoids. Small amounts of coumarins, phenolic carboxylic compounds, phloroglucinol derivatives, monoterpenes, sesquiterpenes, n-alkanes, n-alkanols, carotenoids, and beta-sitosterol are present. The roots contain zanthones. Practitioners and consumers should note that St. Johns Wort extracts, whether standardized or not, consist of other active ingredients in addition to hypericin and pseudohypericin.

Pre-clinical studies

Both in-vitro (test tube) and in-vivo (animal) pre-clinical studies suggest that hypericin (and, to a lesser extent, pseudo-hypericin) may have therapeutic benefits for HIV infection and other retroviral diseases. Certain compounds other than hypericin extracted from Hypericum species have antibiotic activity. marked antiretroviral effects, however, have been reported primarily for hypericin which is isolated mainly from Hypericum perforatum. However, synthetic hypericin has been used in recent studies.

In in-vitro and in-vivo studies, both hypericin and pseudohypericin (extracted from Hypericum triquetifolium) had antiviral activity against several retroviruses. In one experiment, mice were simultaneously injected with low doses of the compounds and with Friend leukemia virus (FV). This aggressive retrovirus normally causes rapid splenomegaly (swelling of the spleen) and acute erythroleukemia in mice. However, these symptoms were effectively suppressed by the addition of hypericin. Splenomegaly had not occurred ten days after infection at the close of the study. No infectious virus could be recovered from the spleen. Also, viremia normally associated with FV was absent. Mice treated with hypericin and pseudohypericin survived a much longer time than mice treated with a toxic antiviral (N3dthd). Unlike most antiretroviral drugs, 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.

In in-vitro studies, mouse cell lines were infected with radiation leukemia virus (Rad LV) and then incubated with hypericin. The activity of reverse transcriptase in these cells was suppressed through indirect mechanisms. In contrast to nucleoside analogues, polycyclic diones such as hypericin interfere directly with the viral replication cycle during stages in which virions are assembled or intact virions are shedded from immature cores. Alternatively, these aromatic compounds may directly inactivate mature retrovirus that contains normal, assembled cores. Other findings indicate that hypericin is able to inactivate virions and block viral release from infected cells by interacting with the cell membrane.

Unpublished data show that hypericin disrupts the formation of synctia in HIV disease as well as in de novo infection of cells. In in-vitro studies, hypericin showed selective activity against HIV and modest inhibition of reverse transcriptase. In vitro research also revealed that hypericin lowered viral activity in whole human blood taken from HIV infected persons. “Wild” strains of HIV taken directly from infected patients are sometimes more resistant to antiviral agents than are viral strains bred in the laboratory.

Other investigations indicate that the antiviral effects of hypericin on murine cytomegalovirus (MCMV), Sindbus virus (SV), and HIV are enhanced by exposure to fluorescent light. Hypericin and to some degree, pseudohypericin, were effective against FV and HSV-1 when the viruses were first incubated with the compounds for one hour at 37 degrees C before mice were infected. Pre-incubation for one hour at 4 degrees C, however, produced no antiviral effects. The authors of this study (who are scientists at Lilly Research Laboratories) reported that hypericin and pseudohypericin were effective in vitro against enveloped viruses such as HSV and influenza when the cultures were pre-incubated with these agents at 37 degrees C. They also correctly showed that hypericin and its analogue inhibit DNA and RNA viruses, but not viruses which lack a lipid envelope. The Lilly researchers, who call AZT a preferred therapy for HIV, however, claim that single dose administration of hypericin is not efficacious. Human clinical trials are needed to evaluate the appropriate dose ranges at which hypericin is therapeutic but nontoxic, and to assess the differences, if any, between natural and synthetic hypericins. In animal studies, natural sources of hypericin (in combination with its analogue, pseudohypericin), showed greater antiviral activity that did synthetic hypericin. Preliminary findings thus far strongly indicate that the wide spectrum antiviral properties of hypericin, its experimental effectiveness at low concentrations, and its unconventional mechanisms of antiviral action make it a promising candidate for a new class of HIV therapies.

Mechanisms of action

Hypericin and pseudohypericin had no effect on purified reverse transcriptase alone. They did not alter levels of intracellular viral mRNA. Instead, hypericin lowers the number of mature viral particles without suppressing intracellular levels of viral mRNA. The concentrations of viral antigens on the cell surface were also unaffected by hypericin. These findings, as a whole, imply that the compounds interfere with viral assembly, budding, shedding or stability at the level of the cell membrane When hypericin was added to viral-infected cell cultures, red fluorescence appeared at localized areas on the lipid surface membrane.

Unlike nucleoside analogues, polycyclic diones such as hypericin have no effects on transcription, translation, or transport of viral proteins to the cell membrane. They are not directly active against reverse transcriptase even though reverse transcriptase activity was reduced in infected cells that had first been incubated with hypericin. Cells treated with hypericin form immature or abnormally assembled cores. This indicates that hypericin may block the processing of gag-encoded precursor polypeptides. Hypericin, whether in the intracellular medium or bounded to the membrane, is thought to lower the activity of reverse transcriptase by interfering with protein synthesis. (It is noteworthy that the antiviral effects of harmine, a photoactive alkaloid, involve disrupted kinase activity in enveloped RNA viruses.)

Viral particles are not formed when gag-related polyproteins fail to be cleaved or synthesized. Gag-related polyproteins, therefore, may play a decisive role in the virucidal actions of hypericin. Reverse transcriptase within the core of the assembled virus probably takes the form of an inactive enzyme or proenzyme. Mechanisms involving viral-encoded proteases or kinases might be required to activate reverse transcriptase. These mechanisms could transform the enzyme from a nonfunctional to a functional state. Both hypericin and pseudohypericin are thought to influence protease activity. In turn, altered protease activity could disrupt the cleavage or synthesis of gag-related polyproteins. As a result, immature viral cores would be formed. Alternatively, by selectively binding to viral polyproteins, hypericin could interfere with the gag and gag-pol polyproteins needed for viral assembly. Thus, hypericin could block the process whereby RNA packages encapsulated viral particles.

Some investigators, however, propose that hypericin lyses infectious virion by interacting directly with the viral envelope instead of disrupting gag-encoded precursor polyproteins or modifying other proteins. In any case, the antiviral properties of hypericin appear to involve its interactions with the cell membrane or cell surface recognition sites. Molecular modifications at or near the surface provide a model for rationally designing a new class of anti-HIV agents. Such therapies may be able to block HIV-encoded protease located in the gag-pol region. Importantly, drugs of this type would not be toxic like AZT and other agents whose pharmacological actions are based on direct inhibition of reverse transcriptase.

The aromatic, ringed structure encircled by six phenolic hydroxy groups seems critical to the antiviral activity of the hypericin molecule. Quinone groups, which often have antiviral properties, also exert photodynamic effects. Hypericin is thought to generate singlet oxygen. However, free radical quenchers can interfere with singlet oxygen reactions involving hypericin thereby reducing its antiviral properties.

Hypericin has a unique molecular structure in which one-half of the molecule is hydrophilic (water loving) while the other half is hydrophobic (water repelling). The top, bottom and side (non-polar) of the hypericin molecule which contains the methyl groups are hydrophobic. It is thought that the molecule might bond to the outer surface of the cell membrane. Presumably, the hydrophobic side would be immersed in fat Singlet oxygen, though less reactive than triplet oxygen, binds with two-electron targets, including, for example, the double bonds found in polyunsaturated fatty acids. The hydrophilic sides, in contrast, could hydrogen-bond to the aqueous media.

Discrepancies between in vivo findings from different studies on the antiretroviral effects of hypericin and pseudo-hypericin may be due partly to variations in light. However, differences in hypericin isolation methods and in the strains of mice used also could account for variable findings in several investigations. The antiviral effects of hypericin are largely but not completely, attributed to its photodynamic properties. In the presence of light, hypericin completely inhibited infection of cell cultures of equine infectious anemia virus (EIAV). On exposure to fluorescent light, hypericin inactivated MCMV, Sindbis virus (SV), and HIV-1. Both membrane virions and virus-infected cells were more strongly inactivated by visible light. (Polyacetylene phenylheptatriyine (PHY), a substance purified from the plant, Bidens pilosa, also shows antiviral activity against membrane-bound viruses such as MCMV. The antiviral effects, which involved interactions between PHY and membrane, occurred in the presence of long wave ultraviolet light). Significant advances in photobiological research have been made in recent years. New findings demonstrate clearly that photodynamic action accounts for the antiviral properties of several natural product derivatives, including hypericin.

Light is required for the photosensitization of hypericin. The compound absorbs light quanta and generates it in the form of singlet oxygen. In so doing, hypericin triggers the photo-oxidation of cellular components, including, for example, the photohemolysis of red blood cells. The underlying mechanism of photodynamic reactions is not fully understood. It is thought to involve interactions between oxygen and light as well as sensitizing pigment which binds to the cell membrane.

In photodynamic reactions mediated by hypericin, singlet oxygen serves as the main oxidant. Singlet oxygen has a strong affinity for pi electron-systems found in compounds such as polycyclic diones. The pi electrons, responsible for the photoactive properties of hypericin, absorb visible and ultraviolet light and then reemit it within the range of green and red light. The two hydroxy groups and the two methyl groups flanking each side of hypericin’s eight ringed structure do not lie within the same plane. Instead, they repel each other, placing strain on the benzenoid structure. This causes the hypericin molecule to twist and become unstable. Hypothetically, the steric strain could increase the energy state of the pi electrons. This would allow them to form temporary bonds with singlet oxygen which, at a later point, could be released to disrupt mechanisms of viral replication. Pi electrons therefore, seem to play a major role in the antiviral activity of hypericin.

The “impressive light-mediated antiviral activities” of hypericin have been shown in several studies. Sindbus virus (SV), for example, was 99% inhibited in the presence of light. In the dark, however, the antiviral effects of hypericin were reduced by more than two orders of magnitude. On exposure to light (650-700nm.), hypericin undergoes type II photosensitization in which singlet oxygen and other reactive molecular species are produced. Though not as destructive as free radicals (which are generated in Type I photosensitization, singlet oxygen could damage viral membranes, thereby interfering with proteins and nucleic acids. Nonetheless, hypericin also has some degree of virucidal activity in the dark, though much less so than in light. It is thought that the antiviral effects produced in the absence of light take place through a different mode of action than light-mediated virucidal activity. Protein kinase C, for example, may represent an alternative target for hypericin’s antiviral action in the absence of light.

One of the therapeutic advantages of hypericin is that it works by multiple steps. Hypericin is probably able to interrupt various phases in the replication of enveloped retroviruses. These stages include polyprotein cleavage and protein alterations as well as assembly, budding and shedding of viral components. The compound’s disadvantages as an anti-HIV agent involve its potential toxicity when patients are exposed to sunlight. Also, it has been reported that in humans, hypericin is more effective in suppressing HSV-1 and HSV-2 than HIV. Future research is required to elucidate the mechanisms through which hypericin generates and reacts with singlet oxygen in triggering antiviral effects.


Clinical trials that were being conducted in early 1990’s by Dr. Bihari in New York City recommend the following regimen. For the first two weeks, patients were given 10 mg of hypericin once a day for two weeks. During the second two weeks, the dosage alternates between 10 mg per day on the first day, 20 mg on the second day, 10 mg on the third day, and so forth. The ultimate dosage was given during the fifth and sixth weeks when patients were given 20 mg per day.

It has been proposed that beta-carotene, a known free radical quencher, be administered in combination with hypericin. Theoretically, this might reduce any toxic side-effects associated with hypericin’s generation of free radicals. Some investigators, however, have warned that quenchers also may lessen the anti-viral properties of hypericin. The role of beta-carotene and other free-radical scavengers in hypericin therapy deserves further clarification.


Hypericin, a pigment molecule with photodynamic activity, has dramatic antiviral activity, especially in the presence of light. Like several other plant derived substances, hypericin only inhibits viruses with membranes. It has antiviral effects against a wide range of retroviruses, including HSV-1, HSV-2, (murine) CMV, and HIV-1. In contrast to nucleoside agents such as AZT, hypericin and its chemical relative, pseudohypericin, do not directly affect the activity of reverse transcriptase. Rather, these agents seem 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 membrane.

Hypericin and related compounds, with their alternative targets for virucidal activity, comprise a new class of potential anti-HIV drugs. It is not yet known how effective hypericin will be in human AIDS. Preliminary findings, however, strongly suggest that this compound is one of the most promising, new anti-HIV prototype molecules currently under investigation.

Trans fats linked to increased endometriosis risk and omega-3-rich food linked to lower risk

Women whose diets are rich in foods containing Omega-3 oils might be less likely to develop endometriosis, while those whose diets are heavily laden with trans fats might be more likely to develop the debilitating condition, new research published today (Wednesday 24 March) suggests.

The study – which is the largest to have investigated the link between diet and endometriosis risk and the first prospective study to identify a modifiable risk factor for the condition – found that while the total amount of fat in the diet did not matter, the type of fat did. Women who ate the highest amount of long-chain Omega-3 fatty acids were 22% less likely to be diagnosed with endometriosis than those who ate the least and that those who ate the most trans fats had a 48% increased risk, compared with those who ate the least.

The findings from 70,709 American nurses followed for 12 years, published online in Europe’s leading reproductive medicine journal Human Reproduction, not only suggest that diet may be important in the development of endometriosis, but they also provide more evidence that a low fat diet is not necessarily the healthiest and further bolster the case for eliminating trans fats from the food supply, said the study’s leader, Dr Stacey Missmer, an assistant professor of obstetrics, gynaecology and reproductive biology at Brigham and Women’s Hospital and Harvard Medical School in Boston, Massachusetts, USA.

‘Millions of women worldwide suffer from endometriosis. Many women have been searching for something they can actually do for themselves, or their daughters, to reduce the risk of developing the disease, and these findings suggest that dietary changes may be something they can do. The results need to be confirmed by further research, but this study gives us a strong indication that we’re on the right track in identifying food rich in Omega-3 oils as protective for endometriosis and trans fats as detrimental,’ Dr Missmer added.

Endometriosis occurs when pieces of the womb lining, or endometrium, is found outside the womb. This tissue behaves in the same way as it does in the womb – growing during the menstrual cycle in response to oestrogen in anticipation of an egg being fertilized and shedding as blood when there’s no pregnancy. However, when it grows outside the womb, it is trapped and cannot leave the body as menstruation. Some women experience no symptoms, but for many it is very incapacitating, causing severe pain. The tissue can also stick to other organs, sometimes leading to infertility. It afflicts about 10% of women. The cause is poorly understood and there is no cure. Symptoms are traditionally treated with pain medication, hormone drugs or surgery.

In the study, the researchers collected information from 1989 to 2001 on 70,709 women enrolled in the U.S. Nurses Health Study cohort. They used three food-frequency questionnaires spaced at four-year intervals to record the woman’s usual dietary habits over the preceding year. They categorized consumption of the various types of dietary fat into five levels and related that information to later confirmed diagnoses of endometriosis. A total of 1,199 women were diagnosed with the disease by the end of the study. The results were adjusted to eliminate any influence on the findings from factors such as total calorie intake, body mass index, number of children borne and race.

Long-chain Omega-3 fatty acids are found mostly in oily fish. They have been linked to reduced heart disease risk. In the study, the highest contributor was mayonnaise and full-fat salad dressing, followed by fatty fish such as tuna, salmon and mackerel.

Trans fats are artificially produced through hydrogenation, which turns liquid vegetable oil into solid fat. Used in thousands of processed foods, from snacks to ready-meals, they have already been linked to increased heart disease risk. Some countries and municipalities have banned them. The major sources of trans fats in this study were fried restaurant foods, margarine and crackers.

‘Women tend to go to the Internet in particular to look for something they can do. The majority of the dietary recommendations they find there are the ones prescribed for heart health, but until now, those had not been evaluated specifically for endometriosis,’ Dr Missmer said. ‘This gives them information that is more tailored and provides evidence for another disease where it is the type of fat in the diet, rather than the total amount, that is important.’

Besides confirming the finding, a next step could be to investigate whether dietary intervention that reduces trans fats and increases Omega-3 oils can alleviate symptoms in women who already have endometriosis, Dr Missmer added.

Source: European Society of Human Reproduction and Embryology

Indian spice may delay liver damage and cirrhosis

Curcumin, one of the principal components of the Indian spice turmeric, seems to delay the liver damage that eventually causes cirrhosis, suggests preliminary experimental research in the journal Gut.

Curcumin, which gives turmeric its bright yellow pigment, has long been used in Indian Ayurvedic medicine to treat a wide range of gastrointestinal disorders.

Previous research has indicated that it has anti-inflammatory and antioxidant properties which may be helpful in combating disease.

The research team wanted to find out if curcumin could delay the damage caused by progressive inflammatory conditions of the liver, including primary sclerosing cholangitis and primary biliary cirrhosis.

Both of these conditions, which can be sparked by genetic faults or autoimmune disease, cause the liver’s plumbing system of bile ducts to become inflamed, scarred, and blocked. This leads to extensive tissue damage and irreversible and ultimately fatal liver cirrhosis.

The research team analyzed tissue and blood samples from mice with chronic liver inflammation before and after adding curcumin to their diet for a period of four and a period of eight weeks.

The results were compared with the equivalent samples from mice with the same condition, but not fed curcumin.

The findings showed that the curcumin diet significantly reduced bile duct blockage and curbed liver cell (hepatocyte) damage and scarring (fibrosis) by interfering with several chemical signalling pathways involved in the inflammatory process.

These effects were clear at both four and eight weeks. No such effects were seen in mice fed a normal diet.

The authors point out that current treatment for inflammatory liver disease involves ursodeoxycholic acid, the long term effects of which remain unclear. The other alternative is a liver transplant.

Curcumin is a natural product, they say, which seems to target several different parts of the inflammatory process, and as such, may therefore offer a very promising treatment in the future.

Source: British Medical Journal

Dietary Supplement Speeds Silver Cyclists

Taking arginine supplements can improve the cycling ability of over-50s. Researchers writing in BioMed Central’s Journal of the International Society of Sports Nutrition tested a combination of the amino acid and an antioxidant in sixteen cyclists, finding that it enhanced their anaerobic threshold — the amount of work done before lactic acid begins to accumulate in the blood.

Zhaoping Li worked with a team of researchers from the University of California, Los Angeles, USA, to carry out the randomized controlled trial. She said, “The loss of exercise capacity with age often results in a reduction in physical fitness and more rapid senescence. A dietary supplement that increases exercise capacity might help to preserve physical fitness by optimizing performance and improving general health and well being in older people.”

One way in which older people may reduce their exercise capacity revolves around the signaling molecule nitric oxide (NO), which is involved in many physiological processes, including those related to working out. NO production diminishes in quantity and availability as we age and is associated with an increased prevalence of other cardiovascular risk factors. In the body, NO is created from the amino acid arginine and is inactivated by oxygen free radicals. By supplementing diet with both the precursor and an anti-oxidant, the researchers hoped to support the NO system in the cyclists and thereby enhance performance.

Sixteen cyclists aged between 50 and 73 were randomly assigned to receive either the supplement or dummy placebo pills. After one week of study, the anaerobic threshold of the supplement group increased, while that of the control group did not significantly alter. This increase in anaerobic threshold was preserved at week three. According to Li, “We’ve demonstrated a 16.7% increase in anaerobic threshold. This indicates a potential role of arginine and antioxidant supplementation in improving exercise performance in elderly.”

ScienceDaily (Mar. 23, 2010)