St Johns Wort or Hypericum perforatum

Hypericum perforatum or St. John’s Wort

From Wikipedia, the free encyclopedia

Hypericum perforatum, known as perforate St John’s-wort, common Saint John’s wort and St John’s wort,[note 1] is a flowering plant in the family Hypericaceae. The common name “St John’s wort” may be used to refer to any species of the genus Hypericum. Therefore, Hypericum perforatum is sometimes called “common St John’s wort” or “perforate St John’s wort” in order to differentiate it. It is a medicinal herb with antidepressant activity and anti-inflammatory properties as an arachidonate 5-lipoxygenase inhibitor and COX-1 inhibitor.

St Johns Wort or Hypericum perforatum

Scientific classification:
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Malpighiales
Family: Hypericaceae
Genus: Hypericum
Species: H. perforatum
Binomial name: Hypericum perforatum

Botanical description:

Hypericum perforatum is native to parts of Europe and Asia but has spread to temperate regions worldwide as a cosmopolitan invasive weed.

The common name “St John’s wort” 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 tradition of hanging plants over religious icons in the home during St John’s Day, to ward off evil.

Perforate St John’s wort is a herbaceous perennial plant with extensive, creeping rhizomes. Its stems are erect, branched in the upper section, and can grow to 1 m high. It has opposite, stalkless, narrow, oblong leaves that are 1–2 cm long. The leaves are yellow-green in color, with scattered translucent dots of glandular tissue. The dots are conspicuous when held up to the light, giving the leaves the ‘perforated’ appearance to which the plant’s Latin name refers. The flowers measure up to 2.5 cm across, have five petals, and are colored bright yellow with conspicuous black dots. The flowers appear in broad cymes at the ends of the upper branches, between late spring and early to mid summer. The sepals are pointed, with black glandular dots. There are many stamens, which are united at the base into three bundles. The pollen grains are ellipsoidal.

When flower buds (not the flowers themselves) or seed pods are crushed, a reddish/purple liquid is produced.

Medical uses:

Common St. John’s-wort has long been used in herbalism. It was known to have medical properties in Classical Antiquity and was a standard component of theriacs, from the Mithridate of Aulus Cornelius Celsus’ De Medicina (ca. 30 CE) to the Venice treacle of d’Amsterdammer Apotheek in 1686. Folk usages included oily extract (“St. John’s oil”) and Hypericum snaps.

Hypericum perforatum is the most potent species and it is today grown commercially for use in herbalism and medicine.

Two main compounds of interest have been studied in more detail: hyperforin and hypericin. As psychiatric medication, it is usually taken as pills, or as tea. Standardised preparations are available, and research has mainly studied alcoholic extracts and isolated compounds. What research data exists supports a noticeable effect in many cases of light and medium depression, but no significant improvement of severe depression and OCD. The red, oily extract of H. perforatum may help heal wounds. Both hypericin and hyperforin are reported to have antibiotic properties. Justifying this view with the then-current doctrine of signatures, herbalist William Coles (1626–1662) wrote in the 17th century that:

“The little holes where of the leaves of Saint Johns wort are full, doe resemble all the pores of the skin and therefore it is profitable for all hurts and wounds that can happen thereunto.”

Hypericum perforatum may also be capable of reducing the physical signs of opiate withdrawal.

Hypericum extract, by inducing both the CYP3A4 and the P-glycoprotein (P-gp), can reduce the plasma concentrations of different antineoplastic agents such as imatinib, irinotecan and docetaxel, thus reducing the clinical efficacy of these drugs.

Major depressive disorder:

Some studies have supported the efficacy of St John’s wort as a treatment for depression in humans, but have not concluded it as a replacement for more studied treatments, and proper medical consultation. A 2015 meta-analysis review concluded that it has superior efficacy to placebo in treating depression; is as effective as standard antidepressant pharmaceuticals for treating depression; and has fewer adverse effects than other antidepressants. The authors concluded that it is difficult to assign a place for St. John’s wort in the treatment of depression owing to limitations in the available evidence base, including large variations in efficacy seen in trials performed in German-speaking relative to other countries. It is proposed that the mechanism of action of St. John’s wort is due to the inhibition of reuptake of certain neurotransmitters.

A 2008 Cochrane review of 29 clinical trials concluded that it was superior to placebo in patients with major depression, as effective as standard antidepressants and had fewer side-effects. According to the National Center for Complementary and Integrative Health (NCCIH) of the National Institutes of Health, it “may help some types of depression, though the evidence is not definitive”; can limit the efficacy of prescription medicines; and psychosis can occur as a rare side effect. The NCCIH notes that combining St John’s wort with certain prescription antidepressants can lead to a “potentially life-threatening increase of serotonin”, a brain chemical targeted by antidepressants. A 2016 review came to the same conclusions as the 2008 Cochrane review, but noted that the quality of evidence in regards to both effectiveness and incidence of adverse effects was reduced relative to that for conventional antidepressants.

In Germany, St. John’s wort is sometimes prescribed for mild to moderate depression, especially in children and adolescents.

Side effects:

St John’s wort is generally well tolerated, with an adverse effect profile similar to placebo. Commonly reported adverse effects include gastrointestinal symptoms (nausea, abdominal pain, loss of appetite, and diarrhea), dizziness, confusion, fatigue, sedation, dry mouth, restlessness, and headache. The organ systems associated with adverse drug reactions to St John’s wort and fluoxetine (an SSRI) have a similar incidence profile; most of these reactions involve the central nervous system. St John’s wort also decreases the levels of estrogens, such as estradiol, by speeding up its metabolism, and should not be taken by women on contraceptive pills as it upregulates the CYP3A4 cytochrome of the P450 system in the liver.

St John’s wort may cause photosensitivity. This can lead to visual sensitivity to light and to sunburns in situations that would not normally cause them. This photosensitivity could lead to cataracts as well as sunburn. Product labeling often recommends avoidance of ultraviolet light exposure.

St John’s wort is associated with aggravating psychosis in people who have schizophrenia.


St. John’s wort has interactions with medications such as SSRI antidepressants, warfarin, and birth control. Combining both St John’s wort and SSRI antidepressants could lead to increased serotonin levels causing serotonin syndrome. It should not be taken with the heart medication, ranolazine. Combining estrogen containing oral contraceptives with St John’s wort can lead to decreased efficacy of the contraceptive and eventually unplanned pregnancies. St. John’s wort has been known to decrease the blood concentrations of immunosuppressants (cyclosporine & tacrolimus), sedatives (midazolam & alprazolam), anticoagulants (phenprocoumon), chemotherapy drugs (irinotecan) and other medications. These are just a few of the drug interactions that St John’s wort possesses. It is also known to decrease the efficacy of HIV medications, cholesterol medications, as well as transplant medications.

Consumption of St. John’s wort is discouraged for those with bipolar disorder. There is concern that people with bipolar depression taking St. John’s wort may be at a higher risk for mania.


Bibliographic details for “Hypericum perforatum”
Page name: Hypericum perforatum
Author: Wikipedia contributors
Publisher: Wikipedia, The Free Encyclopedia.
Date of last revision: 7 December 2017 04:54 UTC
Date retrieved: 8 December 2017 21:17 UTC
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