St John's Wort The Plant Uses Of The Herb Clinical Evidence

Hypericum perforatum is a yellow-flowering, rhizomatous, perennial herb indigenous to Europe, which has been introduced to the Americas and grows wild in many meadows. The name comes from the fact that it traditionally flowers by and is harvested on St John's day ; all above-ground parts are cut and dried for later use in the form of herbal tea, which has long been enjoyed both for its pleasant (though somewhat bitter) taste and for its medicinal properties.

The name perforatum refers to the small windows in the leaves, which can be seen when they are held against the light.

Although Hypericum perforatum is grown commercially in some regions, it is listed as a noxious weed in over twenty countries. Ingestion by livestock can cause photosensitization, central nervous system depression, spontaneous abortion, and can lead to death. Effective herbicides for control of Hypericum include 2,4-D, picloram, and glyphosate. In western North America three beetles Chrysolina quadrigemina , Chrysolina hyperici and Agrilus hyperici have been introduced as biocontrol agents.

2 Uses of the herb

The first recorded use of Hypericum for medicinal purposes dates back to ancient Greece, and it has been used ever since. The herb was also used by Native AmericanNative Americans (also Indians Aboriginal Peoples American Indians First Nations Alaskan Natives or Indigenous Peoples of America are the indigenous inhabitants of Americas prior to the European colonization, and their modern descendants. This term compris internally as an abortifacient and externally as an anti-inflammatory, astringent, and antiseptic.

In modern medicine, standardized Hypericum extract (obtained from H. perforatum) is commonly used as a treatment for depressionIt is common to feel sad, discouraged, or "down" once in a while, and anyone in this state might say they are suffering from depression. But for some people, this mood persists. For depression, or any other condition, to be termed "clinical" it must reach and anxiety disorderAnxiety disorder is a blanket term covering several different forms of fear, phobia and nervous condition, that come on suddenly and prevent pursuing normal daily routines including: general anxiety disorder social anxiety, sometimes known as 'social phobs. In homeopathyHomeopathy (also spelled homoeopathy or homoeopathy , from the Greek words homoios (similar) and pathos (suffering), is a controversial system of alternative medicine involving the use of remedies without chemically active ingredients. The theory of homeo, Hypericum is used in the treatment of numerous medical problems, yet the rate of success has not been adequately documented. Historically, the flowers and stems of St John's wort have also been used to produce red and yellow dyeA dye can generally be described as a coloured substance that has an affinity to the substrate to which it is being applied. The dye is usually used as an aqueous solution and may require a mordant to improve the fastness of the dye on the fibre. In contr.

St. John's wort is today most widely known as a possible treatment for depression. In some countries, such as GermanyThe Federal Republic of Germany ( German: Bundesrepublik Deutschland is one of the world's leading industrialized countries, located in the middle of the European Union. It is bordered to the north by the North Sea, Denmark and the Baltic Sea, to the east, Hypericum is prescribed for mild depression far more commonly than conventional antidepressant medication. Standardized extracts can be bought today as an over-the-counter remedy, usually in tablet or capsule form. It is also available in teabags.

3 Clinical evidence

Clinical studies of St John's wort preparations have mainly focused on the efficacy of the herb in clinical depressionThe word depression can mean: A decrease of functional activity. The everyday term for a sad mood, see depression (mood) The medical condition clinical depression A sunken or depressed geological formation, see depression (geology) An economic depression,. There have been mixed results over the efficacy of St. John's wort in clinical depression. Some studies have found it to be effective in the treatment of mild to moderate depression, with fewer side effects than many conventional antidepressants, whilst others show no benefit over placebo.

3.1 Evidence for efficacy

An early meta-study indicated that extracts of hypericum may be more effective than placebo for the treatment of mild to moderately severe depressive disorders. (Linde et al., 1996) This study, which covered the results from 23 smaller, earlier studies, is perhaps the most often cited by manufacturers and other supporters of St. John's wort.

This meta-analysis study was later updated to include further studies, for a total of 27, to form a Cochrane Review. The updated review found that Hypericum preparations were significantly superior to placebo (rate ratio 2.47; 95% confidence interval 1.69 to 3.61) and similarly effective as standard antidepressants (single preparations 1.01; 0.87 to 1.16, combinations 1.52; 0.78 to 2.94). (Linde & Mulrow, 2003)

Another meta-analysis, with stricter inclusion criteria, found that Hypericum was more effective than placebo; and as effective as tricyclic antidepressants, with fewer adverse drug reactions. (Kim et al., 1999) This meta-analysis showed that the response rate for St. John’s wort was significantly greater than that for placebo (73.2 versus 37.9%, respectively, relative risk 1.48 and 95% CI 1.03–1.92) and similar to that observed with tricyclic antidepressants (64 versus 66.4% for St. John’s wort and tricyclic antidepressants, respectively, relative risk 1.11 and 95% CI 0.92–1.29).

Other more recent trials have also showed greater efficacy than placebo; and comparable efficacy to standard antidepressants with a superior adverse effect profile. (Laakman et al., 1998; Harrer et al., 1999; Philipp et al., 1999)

3.2 Evidence against efficacy

A major study funded by the NIH in the United States, found St John's wort to be ineffective in treating major depression of moderate severity. (Hypericum Depression Trial Study Group, 2002) This study involved 340 patients, diagnosed with severe depression based on DSM-IV criteria and assessed using Hamilton Depression Scale (HAM-D) and Clinical Global Impression (CGI) scores. The trial was a multi-centre randomised double-blind placebo-controlled trial, comparing one preparation of St John's wort to sertraline and placebo. St. John's wort proved no more effective than placebo in alleviating moderately severe major depression. It should be noted that sertraline was also no better than placebo in this study, based on the primary outcome measure (HAM-D). Further studies on the herb's efficacy in alleviating mild depression are planned by the NIH.

As with most studies into complementary therapies, many are hampered by poor methodologies and study designs; preventing definitive evidence from emerging. The author of one of the trials with positive results stated that, "Further studies comparing hypericum with standard antidepressants in well defined groups of patients over longer observations periods, investigating long term side effects, and comparing different extracts and doses are needed." (Linde & Mulrow, 2003)

4 Pharmacology

Although the exact mechanism by which St. John's wort works is unclear, it is believed to involve inhibition of 5-HT reuptake, much like the conventional SSRI antidepressants. It should be noted that the exact mechanism of even the conventional antidepressants is subject to much conjecture.

The major active constituents in St John's wort are thought to be hyperforin and hypericin, although other biologically active constituents present, e.g. flavonoids and tannins, may also be involved. (Nahrstedt & Butterweck , 1997)

Hyperforin is believed to be the major constituent responsible for antidepressant activity, and has been shown to inhibit the uptake of 5-HT, dopamine, noradrenaline, GABA and glutamate. (Chatterjee et al., 1998a) Discrepancies in the dose-response relationship imply that constituents other than hyperforin are likely to also be involved. (Chatterjee et al., 1998b)

5 Dose/Formulations

The dosage of St John's wort preparations vary greatly between formulations, due to variability in the plant source and preparation processes. The doses of St. John’s wort extract used in clinical trials generally range from 350 to 1800 mg daily (equivalent to 0.4 to 2.7 mg hypericin depending on the preparation). (Linde & Mulrow, 2003)

The recommended dosage for various forms of St John's wort as recommended by the British Herbal Medicine Association Scientific Committee (1983) are as follows:

dried herb: 2-4 g or by infusion three times daily
liquid extract 2-4 mL (1:1 in 25% alcohol) three times daily
tincture 2-4mL (1:10 in 45% alcohol) three times daily

In markets where standardised extracts are not available, the potency of samples can vary widely. Some brands of over-the-counter St. John's wort can be much more potent than others. The same can even be true of two dosage units from different batches of the same brand. Even where extracts are standardised it is debatable whether using hypericin as the standard is useful, since hyperforin is believed to be the main active constituent.

As with other antidepressants, Hypericum should be taken for at least four weeks before its effectiveness can be properly assessed.

6 Adverse effects

St John's wort is generally well tolerated, with an adverse effect profile similar to placebo. (Ernst et al., 1998). The most common adverse effects reported are gastrointestinal symptoms, dizziness, confusion and tiredness/sedation. (Barnes et al., 2002)

St John's wort is also known cause photosensitivity , which can lead to sunburns in situations that would not normally cause them, but the incidence is reported to be extremely rare. (Ernst et al., 1998).

7 Drug interactions

St John's wort has been shown to cause multiple drug interactions through induction of the cytochrome P450 enzyme CYP3A4. The principal constituent thought to be responsible is hyperforin which, unfortunately, is also believed to be the active constituent.

St John's wort decreases the levels of certain medications in the body thereby decreasing their efficacy. Such medications may include other antidepressants ( SSRIs and TCAs), contraceptives, cholesterol-lowering medications, etc. Patients on any medications (including over-the-counter) are advised to consult their pharmacist or physician prior to taking any product containing St John's Wort.

8 References

Barnes J, Anderson LA, Phillipson JD (2002). Herbal Medicines: A guide for healthcare professionals (2 ed.) London: Pharmaceutical Press. BooksEnthsiast.com
British Herbal Medicine Association Scientific Committee (1983). British Herbal Pharmacopoeia. West Yorkshire: British Herbal Medicine Association. BooksEnthsiast.com
Chatterjee SS, Bhattacharya SK, Wonnemann M, Singer A, Muller WE (1998a). Hyperforin as a possible antidepressant component of hypericum extracts. Life Sci 63 (6), 499-510.
Chatterjee SS, Noldner M, Koch E, Erdelmeier C (1998b). Antidepressant activity of hypericum perforatum and hyperforin: the neglected possibility. Pharmacopsychiatry 31 Suppl (1), 7-15.
Ernst E, Rand JI, Barnes J, Stevinson C (1998). Adverse effects profile of the herbal antidepressant St. John's wort (Hypericum perforatum L.). Eur J Clin Pharmacol 54 (8), 589-94.
Harrer G, Schmidt U, Kuhn U, Biller A (1999). Comparison of equivalence between the St. John's wort extract LoHyp-57 and fluoxetine. Arzneimittelforschung 49 (4), 289-96.
Hypericum Depression Trial Study Group (2002). Effect of Hypericum perforatum (St John's Wort) in Major Depressive Disorder. JAMA 287 (14), 1807-1814.
Kim HL, Streltzer J, Goebert D (1999). St. John's Wort for Depression: A Meta-Analysis of Well-Defined Clinical Trials. J Ment Nerv Dis 187 (9), 532-538.
Laakmann G, Schule C, Baghai T, Kieser M (1998). St. John's wort in mild to moderate depression: the relevance of hyperforin for the clinical efficacy. Pharmacopsychiatry 31 Suppl (1), 54-9.
Linde K, Ramirez G, Mulrow CD, Pauls A, Weidenhammer W, Melchart D (1996). St John’s wort for depression – an overview and meta-analysis of randomised clinical trials. BMJ 313, 253–258.
Linde K, Mulrow CD (2003). St John's wort for depression (Cochrane Review). In: The Cochrane Library, Issue 3, 2004. Chichester, UK: John Wiley & Sons, Ltd.
Nahrstedt A, Butterweck V (1997). Biologically active and other chemical constituents of the herb of Hypericum perforatum L. Pharmacopsychiatry 30 Suppl (2), 129-34.
Philipp M, Kohnen R, Hiller KO (1999). Hypericum extract versus imipramine or placebo in patients with moderate depression: randomised multicentre study of treatment for eight weeks. BMJ 319 (7224), 1534-8.

9 External links

See http://www.cc.nih.gov/about/news/press_room/2000/02_10_00_wortfinal.html for an example of drug interactions with St. John's wort
St John's wort information website note: site set up by interested party
QuackWatch article on St. John's wort Criticism of the use of St. John's wort to treat depression.

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