St John's wort

St John's wort (Hypericum perforatum): St John's wort is widely known as a herbal treatment for depression. An analysis of twenty-nine clinical trials with more than five thousand patients was conducted by Cochrane Collaboration.

The review concluded that extracts of St. John's wort were superior to placebo in patients with major depression. St. John's wort had similar efficacy to standard antidepressants.

The rate of side effects was twice lower than for newer SSRI antidepressants and five times lower than for older tricyclic antidepressants. However, this review also noted that studies more favourably supporting the effects of St. John's wort as an antidepressant, were predominantly from German-speaking countries.

Hypericum perforatum is a yellow-flowering, stoloniferous or sarmentose, perennial herb indigenous to Europe, which has been introduced to many temperate areas of the world and grows wild in many meadows. The common name comes from its traditional flowering and harvesting on St John's day, 24 June. The genus name Hypericum is derived from the Greek words hyper (above) and eikon (picture), in reference to the traditional use of the plant to ward off evil, by hanging plants over a religious icon in the house during St John's day. The species name perforatum refers to the presence of small oil glands in the leaves that look like windows, which can be seen when they are held against the light.

The exact mechanism by which St John's wort functions is unclear and subject to conjecture. The St John's wort mechanism is believed to involve inhibition of serotonin (5-HT) reuptake, much like the conventional selective serotonin reuptake inhibitor (SSRI) antidepressants. The major active antidepressive constituents in St John's wort are thought to be hyperforin and hypericin, although other biologically active constituents present, for example, flavonoids and tannins, may also be involved.

Some believe that hyperforin is the major constituent responsible for antidepressant activity, and it has been shown to inhibit the uptake of 5-HT, dopamine, and noradrenaline. Hyperforin also has affinity for GABA and glutamate receptors. On the other hand, a hyperforin-free extract of St John's wort (Ze 117 - Remotiv) may still have significant antidepressive effects.

From the Spanimax List: "15 Top Herbs II"

References:

• Biologically active and other chemical constituents of the herb of Hypericum perforatum L; Nahrstedt A, Butterweck V
• Current St John's wort research from mode of action to clinical efficacy; Müller WE
• St John's wort for major depression; Linde K, Berner MM, Kriston L
• St. John's wort; University of Maryland. Medical Center.
• A review of herbal medicines for psychiatric disorders; Beaubrun G, Gray GE
• Potential use of medicinal plants in the treatment of alcoholism; Carai MAM, Agabio R, Bombardelli E.