Alternative names: Hypericum or Hypericum perforatum. Sometimes misspelled as St. John's Wart.
St. John's Wort is a perennial herb, standing one to two feet high, bearing many bright yellow flowers. It is a shrubby plant, native to many parts of the world including Europe and the United States.
Many of the active ingredients are found in tiny dark spots located on the edges of the five-petalled flowers or on the upper leaves. St. John's Wort is usually sold dried and in concentrated drops, tinctures and extracts.
While St. John's wort has been used in teas, the active ingredients are usually best extracted with a hydroalcoholic solvent. Both tinctures and liquid extracts of Hypericum are common among both modern and ancient herbalist. These hydroalcoholic extractions are deep red and quite aromatic. St. John's wort is also infused in olive oil for topical use.
Rarely are tinctures, liquid extracts or oils tested for the amount of active (or marker) ingredients. To better identify the activity of Hypericum, researchers in Europe began to standardize the powdered extracts of the plant. Hypericin, a naphthodianthrone, was chosen as the component in which to standardize the extracts of St. John's wort. While Hypericum contains two similar naphthodianthrones (hypericin and pseudohypericin), as well as many flavonoids (quercetin, quercetin, amentoflavones, hypericin, xanthones, rutin, and more), they seem to be extracted by similar conditions. Most researchers believe that the standardization of St. John's wort extract to hypericin is a sufficient market at this time, even though other components may be primarily responsible for the medicinal activity. St. John's wort extracts can be standardized from 0.1 to 2.5% hypericin, although the 0.3% hypericin extract is the best studied and is sufficiently economical as a therapeutic agent.
The extract of hypericum (hypericin) has shown a wide variety of effects including psychotropic and antidepressant. It has been theorized that depression results from decreased serotonin levels in the brain. The action of hypericin appears to be based on the its ability to inhibit monoamine oxidase inhibitors; a class of enzymes involved in serotonin degradation. When researchers measured urinary metabolites of noradrenaline and dopamine following administration of St. John's Wort, they found significant increases in 3-methoxy-4-hydroxyphenylglycol (a marker commonly used to measure the effectiveness of antidepressive drugs).
Several activities and active components have been identified in extracts of Hypericum perforatum. In vitro experiments have detected MAO inhibition in extracts of Hypericum. This activity is attributed to hypericin and the xanthones, although the activity has not been shown to be strong enough to be responsible for the clinical activity of the extract. Further experiments need to be conducted to see what role, if any, MAO inhibition plays in the activities of St. John's wort extracts.
There have been many promising in vitro studies showing the inhibition of serotonin receptor expression and serotonin uptake using extracts of Hypericum. This mechanism as well needs to be tested further in order to determine how much of a role it plays in the activities of St. John's Wort extracts.
These activities, as well as a vast history of use in depressive disorders have made St. John's wort quite popular in Europe and now the United States.
There have been numerous studies comparing St. John's wort with other antidepressants. In general, St. John's wort extracts have shown to be as effective in treating mild to moderate depression without the side-effects associated with the pharmaceutical antidepressants. A dose of 300mg, three times daily (900mg total per day) of the 0.3% hypericin extract was used for most of these studies.
In one double-blind study, hypericum has been shown to be an effective treatment of seasonal affective disorder. When compared to antidepressant drugs, hypericum demonstrated comparable results without the side-effects associated with antidepressants. Well-controlled research shows that St. John's Wort alleviates symptoms of depression, particularly seasoned effective disorders (SAD).
St. John's wort is also being investigated as an antiviral agent, as many preliminary studies have shown it to be quite active in this area. I has been used as a topical arthritic wound and burns healer and an oral remedy to treat various viral conditions. Studies show that it is sedative and has anxious properties. St. John's Wort oil is said to be good for the healing of burns and deep lacerations where nerve damage is likely.
An average dose of a standardized extract containing 0.3 percent hypericin is 200 to 300mg.
While no adverse reactions have been recorded, mixing St. John's Wort extracts with other antidepressants is not advised, without the supervision of a qualified health care professional.
The antidepressant effects of St. John's Wort may not be apparent until it is taken daily for three to four weeks.
The most common side-effects from taking St. John's Wort are mild nausea, stomach ache, lack of appetite and tiredness, although these are not common. A very small percentage of people taking high daily doses of St. John's Wort may experience increased sensitivity to sunlight.
Those taking St. John's Wort should be cautioned about eating foods that are known to interact with monoamine oxidase inhibitors (tyramine-containing foods such as cheese, beer, wine, pickles, herring, yeast, etc.).
St. John's Wort appears to work at least in part as an SRI (Serotonin Reuptake Inhibitor). Combining an SRI with an MAO inhibitor can produce a dangerous rise in blood pressure; after stopping use of MAO inhibitors, one should wait four weeks before taking any SRIs. This caution is not based on specific medical research on hypericum and MAO inhibitors, but on what is known about prescription SRIs and MAO inhibitors. Until further research is done on how and why hypericum works to alleviate the symptoms of depression, hypericum should be considered an SRI and treated accordingly.
Very rarely, with a group of antidepressants known as SSRI (Selective Serotonin Reuptake Inhibitors) such as Prozac, antiserotonergic syndrome could occur – characterized by confusion, tremors and sweating. In The Lancet (February 12, 2000) there were two reports of how one of the constituents of St. Johns Wort interfered with an intestinal drug transporter (p-glycoprotein). This caused a decrease of the availability of the cyclosporin, digoxin, dexamethasone (a cortisone drug), Propulsid, Cozar, Theophylline, and Coumadin. Additionally, another report indicated the new AIDS drug, Indinavir, had less than an adequate blood level in patients taking St. Johns Wort.
In short, be careful if you are taking any drugs – unfortunately, your physician may not know about these interactions.
St. John's Wort has been shown to have a 60% to 70% response rate in adult patients with mild-to-moderate depression. A 2001 study found St. John's Wort (300mg extract per day) effective in children with mild to moderate depression also. Ratings of "good" or "excellent" were found by physicians to be 72% after 2 weeks, 97% after 4 weeks and 100% after 6 weeks. The ratings by parents were 65% after 2 weeks, 93% after 4 weeks and 98% at 6 weeks. The medication was tolerated well. [Phytother. Res 2001; 15: pp.367-70]
A large trial compared St. John's wort extract with sertraline (Zoloft) and a placebo in adults with depression. The trial found that neither St. John's wort nor sertraline were more effective than placebo in treating major depression. Most successful trials with St. John's wort have focused on persons with milder forms of depression. St. John's wort should be used primarily for mild to moderate depression as well as dysthymia. [JAMA 2002;287: pp.1807-14]