Hypericum perforatum, also known as St. John's Wort, is part of the Hypericaceae (Linde & Ramirez 1996). It is a perennial herb that branches profusely from a creeping stem and is often found in disturbed areas. This species has been found to be effective in treating mild to moderate depression (De Smet & Nolen 1996), as well as anxiety and insomnia (Anon. 1997a). In Germany, where the use of herbal medicine is quite extensive (DeSmet & Nolen 1996), about 66 million daily doses of hypericin are taken annually. In contrast, in the U.S., its uses have not been evaluated by the FDA and is thus still considered only a dietary supplement (Apgar 1998).
While H. perforarum has been found to contain flavonoids, phloroglucinols, xanthones (Linde & Ramirez 1996; Anon. 1997a), and bioflavonoids (Linde & Ramirez 1996), the main constituent associated with the healing power of the plant is hypericin, a napthodianthrone (Anon. 1997a). In fact, in Germany, the dosage of St. John's Wort is standardized based on the hypericin content (Anon. 1997a; Apgar 1998). Hypericum extracts work by inhibiting the uptake of the neurotransmitters serotonin, norepinephrine, and dopamine, and have been shown to bind to GABA receptors in vitro (Anon. 1997a; Apgar 1998). It has also been found that hypericin does not cross the blood brain barrier, and one proposed method of its action is through mediation of cytokine production of peripheral blood mononuclear cells (Hamdy 1998).
In Europe, studies done on patients having mild depression and taking low doses of hypericin (<.2 mg per day) have shown improvement (61%), while 75% of these patients had an even better response with an even higher dose (27 mg per day) (Hamdy 1998). More extensive testing is needed for H. perforatum as most studies have only lasted four to six weeks (Linde & Ramirez 1996). A better look at long term effects is also necessary.
Probably the largest recent study on the plant consisted of a meta-analysis of 23 European studies involving 1,757 people, and was published in the August 3, 1996 issue of the British Medical Journal (Linde & Ramirez 1996; Anon 1997a; Apgar 1998). Hypericum extracts proved to be significantly superior to placebo (ratio=2.67; 95% confidence interval 1.78 to 4.01) and almost equally as effective as other standard anti-depressants such as imipramine (Tofranil) and desipramine (Norpramin) (Linde & Ramirez 1996; Anon 1997b)
While H. perforatum shows great therapeutic promise, it does appear to have some side effects. The most common complaints include dry mouth, dizziness constipation, some gastrointestinal symptoms and confusion (Anon 1997a; Apgar 1998). Photosensitivity has been reported in grazing animals (Anon 1997a; Apgar 1998) and also in one human (Anon 1997a; Apgar 1998; Bove 1998), probably due to the hypericin.
A 35-year-old woman who took whole, ground St. John's Wort was diagnosed as having subacute polyneuropathy upon exposure to the sun. After approximately four weeks of taking Hypericum extract and having normal exposure to the sun, the woman developed a stinging pain on her arms and face after four weeks of use (areas generally exposed to the sun). The woman sought help after the pain on her arms and legs developed similar symptoms after sunbathing. When St. John's Wort was withdrawn, the symptoms began to improve in about three weeks and disappeared after months. Due to her symptoms and time of recovery, it appeared she had demyelination of cutaneous axons. Due to the fact that she had no motor or other sensory disturbances, she was diagnosed as having subacute toxic neuropathy. It has been shown that the photoactive hypericins are known to produce free radicals when exposed to sunlight, which may cause lipid peroxidation and myelin damage. Other photosensitivity complaints have been confined to skin color changes (Bove 1998).
People sometimes choose St. John's Wort because it often seems to have fewer side effects than other common antidepressants, and it is much cheaper. St. John's Wort generally costs about 60 cents per day, while fluoxetine can cost $2.50 or more per day. Individuals taking prescription antidepressants should not switch to St. John's Wort without consulting their physician. Discontinuing the use of a regular antidepressant may cause a relapse of depression as well as dizziness, nausea, and diarrhea. St. John's Wort should also not be taken while using another antidepressant. More research on the subject is needed to fully determine what dosage of St. John's Wort is healthy, and at this point, approval by the FDA has still not been given (Anon 1997b).
Apgar, B., 1998. Effect of Saint John's Wort as Treatment For Depression. American Family Physician 57 (6): 1397.
Bove, G. M., 1998. Acute Neuropathy Atter Exposure to Sun in a Patient Treated with St. John's Wort. Lancet. 352 (9134): 1121.
De Smet, P.A.G.M. and W.A. Nolen. 1996. St. John's Wort as an Antidepressant. British Medical Journal. 313 (7052): 241.
Hamdy, R. C.. 1998. St. John's Wort for Depression, Southern Medical Journal. 91 (8): 788.
Linde, K. and G. Ramirez. 1996. St. John's Wort for Depression--an Overview and Meta-Anaiysis of Randomized Clinical Trials. British Medical Journal. 313 (7052): 253.
Anon. 1997b. Listening to St. John's Wort. Harvard Health Letter. 23 (1).
Anon. 1997a. St. John's Wort. Medical Letter on Drugs and Therapeutics. 39 (l0l4): 107.
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