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Photo copyright Steven Foster |
St. John’s Wort (Hypericum perforatum)
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Photo copyright Steven Foster |
Parts used and where grown: St. John’s wort is found in Europe and the United States; it is especially abundant in Northern California and Southern Oregon. The flowering tops are used.
In what conditions might St. John’s wort be supportive?
| • anxiety | • infection
• vitiligo |
Historical or traditional use: In ancient Greece, the herb was used to treat many ailments, including sciatica and poisonous reptile bites. In Europe, St. John’s wort was, and continues to be, very popular for the topical treatment of wounds and burns. It is also a folk remedy for kidney and lung ailments as well as depression.
Active constituents: St. John’s wort has a complex and diverse chemical makeup. Hypericin and pseudohypericin are believed to have antidepressive and antiviral properties.1 Other constituents, such as xanthones and flavonoids, may also contribute to the medicinal actions of St. John’s wort.2
The mechanism by which St. John’s wort acts as an antidepressant is not fully understood. Early research indicated that this herb mildly inhibits the enzyme monoamine oxidase (MAO). MAO is responsible for the breakdown of two brain chemicals—serotonin and norepinephrine. By inhibiting MAO and increasing norepinephrine, St. John’s wort may exert a mild antidepressive action. The antidepressant (or mood elevating) effects of St. John’s wort were originally thought to be due solely to hypericin,3 but hypericin does not act alone. As with many herbal medicines, St. John’s wort relies on the complex interplay of many constituents (e.g., xanthones and flavonoids) for its antidepressant actions.4 St. John’s wort may also block the receptors that bind serotonin.5
How much should I take? Many people take 500 mg per day of herbal extract, tablets, or capsules of St. John’s wort standardized to contain 0.2% hypericin. Higher intakes of St. John’s wort extract, such as 900 mg per day, may be used in some instances. St. John’s wort should be taken close to meals. If used to support depression treatment, its effectiveness should be assessed by a nutritionally oriented doctor after four to six weeks. Herbal tinctures are also available; they are often taken as 1-2 ml three times per day.
Are there any side effects or interactions? St. John’s wort makes the skin more light-sensitive. Persons with fair skin should avoid exposure to strong sunlight and other sources of ultraviolet light, such as tanning beds. It is also advisable to avoid tyramine-containing foods like red wine, cheese, yeast, and pickled herring. St. John’s wort should not be used at the same time as prescription antidepressants (such as Prozac or Nardil). St. John’s wort should not be used during pregnancy or lactation.
References:
1. Weiss RF. Herbal Medicine. Gothenberg, Sweden:
Ab Arcanum, 1988, 295-7.
2. Hö J. Constituents and mechanism of action of
St. John’s wort. Zeitscrhift Phytother 1993;14:255-64.
3. Suzuki O, Katsumata Y, Oya M. Inhibition of
monoamine oxidase by hypericin. Planta Med 1984;50:272-4.
4. Hö J, Demisch L , Gollnik B. Investigations
about antidepressive and mood changing effects of Hypericum perforatum. Planta Med 1989;
55:643.
5. Reichert RG. St. John’s Wort for depression.
Quart Rev Nat Med, 1994;summer:17-18
Copyright © 1998 Virtual Health, LLC
It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your physician, nutritionally-oriented health care practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.The information presented in HealthNotes Online is for informational purposes only.
