Hypericum perforatum
Hypericum perforatum | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Malpighiales |
Family: | Hypericaceae |
Genus: | Hypericum |
Section: | Hypericum sect. Hypericum |
Species: | H. perforatum
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Binomial name | |
Hypericum perforatum | |
Subspecies | |
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Synonyms | |
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Hypericum perforatum, commonly known as St John's wort, is a
The species produces numerous
Description
Hypericum perforatum is an
Its stems are erect and branched in the upper section, and usually range from 0.3 metres to 1 metre in height.[3] The stems are woody near their base and look like they have segmented joints from the scars left behind after the leaves fall off.[4] The stems of H. perforatum are rusty-yellow to rosy in color with two distinct edges and usually have bark that sheds near the base. The stems persist through the winter and sprout new growth with flower buds in the following year; first year growth does not produce flowers.[2]
It has leaves that attach on
Flowering characteristics
The flowers are conspicuous and showy, measuring about 1.5–2.5 cm across, and are bright yellow with black dots along the edges of the petals.[9][2][10] Each of the flowers normally has five large petals and five smaller leaf-like sepals below them. The sepals are about 4–5 mm in length, green in color, are shaped like the head of a spear (lanceolate shape) with a pointed tip, and the same clear and black glands as the leaves. The petals are significantly longer, 8–12 mm in length, and have an oblong shape. They completely hide the sepals from the front side of the flower.[11] The many bright yellow stamens are united at the base into three bundles.[11] The stalk portion of the stamens, the filaments, vary in length and stick out in every direction from the center of the flower.[2] The pollen grains are pale brown to orange in color.[12]
The flowers are arranged along one side of each flowering stem with two flowers at each node (a helicoid cyme) at the ends of the upper branches, between late spring and early to mid-summer.[13] Each flowering stem bears many flowers, between 25 and 100, and also is quite leafy.[11]
The fruit of Hypericum perforatum is a capsule 7–8 mm in length containing the seeds in three valved chambers.
Similar species
Hypericum maculatum is visually similar to Hypericum perforatum; however, its stems have four ridges instead of two and are also hollow. In addition, its leaves have fewer translucent glands and more dark glands. H. maculatum is native to the Old World but has also been introduced to North America.[3]
In North America several native species may be confused with Hypericum perforatum. Hypericum anagalloides is a low-growing creeping plant with rounder leaves and fewer stamens. Hypericum boreale is a smaller plant with more delicate flowers. Hypericum canadense has smaller flowers with sepals that show between the petals. Hypericum concinnum has flowers with petals that bend backward at the tip and also has much narrower, gray-green leaves. Growing in riparian areas along rivers, Hypericum ellipticum has wider leaves with a more elliptic shape. Hypericum scouleri has leaves that are broader at the base and also thicker. All except for H. concinnum grow in environments that are generally more moist than where H. perforatum is found.[3]
Phytochemistry
The most common active chemicals in Hypericum perforatum are hypericin and pseudohypericin (naphthodianthrones), and hyperforin (a phloroglucinol derivative).[13][15][16] It also contains a host of essential oils, the bulk of which are sesquiterpenes.[13] In the wild, the concentrations of any active chemicals can vary widely among individual plants and populations.[17]
Compound | Conc.[18] [20] |
log P | PSA | pKa | Formula | MW |
CYP1A2 [Note 1] |
CYP2C9 [Note 2] |
CYP2D6 [Note 2] |
CYP3A4 [Note 2] |
PGP [Note 2] |
t1/2[20] (h) | Tmax[20] (h) | Cmax[20] (mM) | CSS[20] (mM) | Notes/Biological activity[Note 3] |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Phloroglucinols (2–5%) | ||||||||||||||||
Adhyperforin | 0.2–1.9 | 10–13 | 71.4 | 8.51 | C36H54O4 | 550.81 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? |
Hyperforin | 2–4.5 | 9.7–13 | 71.4 | 8.51 | C35H52O4 | 536.78 | + | +/- | – | + | + | 3.5–16 | 2.5–4.4 | 15-235 | 53.7 | – |
Naphthodianthrones (0.03-3%)
| ||||||||||||||||
Hypericin | 0.003-3 | 7.5–10 | 156 | 6.9±0.2 | C30H16O8 | 504.44 | 0 | – (3.4 μM) |
– (8.5 μM) | – (8.7 μM) |
? | 2.5–6.5 | 6–48 | 0.66-46 | ? | ? |
Pseudohypericin | 0.2–0.23 | 6.7±1.8 | 176 | 7.16 | C30H16O9 | 520.44 | ? | ? | ? | ? | ? | 24.8–25.4 | 3 | 1.4–16 | 0.6–10.8 | – |
Flavonoids (2–12%) | ||||||||||||||||
Amentoflavone |
0.01–0.05 | 3.1–5.1 | 174 | 2.39 | C30H18O10 | 538.46 | ? | – (35 nM) |
– (24.3 μM) | – (4.8 μM) |
? | ? | ? | ? | ? | ? |
Apigenin | 0.1–0.5 | 2.1±0.56 | 87 | 6.63 | C15H10O5 | 270.24 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? |
Catechin | 2–4 | 1.8±0.85 | 110 | 8.92 | C15H14O6 | 290.27 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? |
Epigallocatechin |
? | −0.5–1.5 | 131 | 8.67 | C15H14O6 | 290.27 | ? | ? | ? | ? | ? | 1.7±0.4a | 1.3–1.6a | ? | ? | ? |
Hyperoside | 0.5-2 | 1.5±1.7 | 174 | 6.17 | C21H20O12 | 464.38 | ? | ? | ? | ? | ? | ? | ? | ? | ? | |
Kaempferol | ? | 2.1±0.6 | 107 | 6.44 | C15H10O6 | 286.24 | ? | ? | ? | +/- | ? | ? | ? | ? | ? | ? |
Luteolin | ? | 2.4±0.65 | 107 | 6.3 | C15H10O6 | 286.24 | – | ? | ? | ? | ? | ? | ? | ? | ? | ? |
Quercetin | 2–4 | 2.2±1.5 | 127 | 6.44 | C15H10O7 | 302.24 | – (7.5 μM) b |
– (47 μM) b |
– (24 μM) b |
– (22 μM) b |
– | 20–72c | 8c | ? | ? | ? |
Rutin | 0.3–1.6 | 1.2±2.1 | 266 | 6.43 | C27H30O16 | 610.52 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? |
Phenolic acids (~0.1%) | ||||||||||||||||
Caffeic acid | 0.1 | 1.4±0.4 | 77.8 | 3.64 | C9H8O4 | 180.16 | ? | ? | ? | – | ? | ? | ? | ? | ? | ? |
Chlorogenic acid | <0.1% | -0.36±0.43 | 165 | 3.33 | C16H18O9 | 354.31 | 0 | 0 | 0 | 0 | ? | ? | ? | ? | ? | ? |
Acronym/Symbol | Meaning |
---|---|
MW | Molecular weight in g•mol−1. |
PGP | P-glycoprotein |
t1/2 | Elimination half-life in hours
|
Tmax | Time to peak plasma concentration in hours |
Cmax | Peak plasma concentration in mM |
CSS | Steady state plasma concentration in mM |
Partition coefficient. | |
PSA | angstroms (Å2). Obtained from PubChem
|
Conc. | These values pertain to the approximation concentration (in %) of the constituents in the fresh plant material |
– | Indicates inhibition of the enzyme in question. |
+ | Indicates an inductive effect on the enzyme in question. |
0 | No effect on the enzyme in question. |
5-HT | 5-hydroxytryptamine – synonym for serotonin. |
DA | Dopamine |
NE | Norepinephrine |
GABA | γ-aminobutyric acid |
Glu | Glutamate |
Gly | Glycine |
Ch | Choline |
a | ? |
b | ? |
c | ? |
Notes:
- ^ In brackets is the IC50/EC50 value depending on whether it is an inhibitory or inductive action being exhibited, respectively.
- ^ a b c d As with last note
- ^ Values given in brackets are IC50/EC50 depending on whether it is an inhibitory or inductive action the compound displays towards the biologic target in question. If it pertains to bacterial growth inhibition the value is MIC50
Taxonomy
Hypericum perforatum was selected to be the type species around which the genus Hypericum is based because of its wide cosmopolitan distribution; it is the most common species of the genus in many of the areas it is found, and is one of the most widely known plants among the St John's worts in folklore and medicine.[21] The current accepted placement of H. perforatum within its genus can be summarized as follows:[22]
- Hypericum subg. Hypericum
- Hypericum sect. Hypericum
- Hypericum subsect. Hypericum
- Hypericum ser. Senanensia
- Hypericum ser. Hypericum
- Hypericum subsect. Hypericum
- Hypericum sect. Hypericum
Phylogeny
Hypericum perforatum has a
H. maculatum subsp. immaculatum (16) × H. attenuatum (16)×2 = H. perforatum (32)
Because of its hybrid origins, Hypericum perforatum is one of the few species within its genus that is able to further hybridize with other species, specifically those within H. ser. Hypericum. The hybrids that are descended from H. perforatum can be triploid (3 sets of chromosomes) to hexaploid (6 sets), depending on the chromosome count of the second parent species and the ploidy of the specific H. perforatum gamete that is fertilized or is fertilizing. The triploid offspring exhibit and a mix of traits from the two parents and pass them on to their offspring; the tetraploids also have a mix of traits, but often do not pass on the traits of both parents; the pentaploids are rarely distinguishable from H. perforatum. Because of this, after many generations of hybridization a wide range of traits on a spectrum between the two hybridizing species can be observed in the wild.[23]
Crossed with | Hybrid name | Chromosome number[a 1] |
---|---|---|
H. elegans | H. perforatum × elegans | 2n = 32? |
H. tetrapterum | H. × medium | 2n = 24? |
H. maculatum ssp. maculatum | H. × desetangsii nssp. carinthiacum | 2n = 24/40 |
H. maculatum ssp. immaculatum | H. × desetangsii nssp. balcanicum | 2n = 24/40? |
H. maculatum ssp. obtusiusculum | H. × desetangsii nssp. desetangsii | 2n = 40 |
|
Etymology and common names
The
The common name St John's wort comes from the fact that its flowers and buds were commonly harvested at the time of the Midsummer festival, which was later Christianized as St John's Feast Day on 24 June. It was believed that harvesting the flower at this time made its healing and magical powers more potent. The herb would be hung on house and stall doors on St John's Feast Day to ward off evil spirits and to safeguard against harm and sickness to people and livestock. In other traditions it was burned in bonfires for the protection of crops along with other herbs believed to be magical.[25][26] Because of its supposed potency in warding off spirits, the plant was also known as fuga daemonum (loosely "demon-flight").[27] Many other similarly fanciful names have been used for it including devil's scourge, Lord God's wonder plant, and witch's herb.[28] In medieval Kent it was called herbe Ion (Ion in this case referring to "John") as recorded in the poem The Feate of Gardening.[29] Other local names for Hypericum perforatum include balm of the warrior's wound in Somerset, penny John in Norfolk, rosin rose in Yorkshire, and touch-and-heal in Northern Ireland.[26] Locally in the United States, it may also be referred to as Tipton-weed, goatweed, or Klamath weed.[30][31]
In the 21st century, any species of the genus Hypericum can be referred to as St John's wort. Therefore, it is more accurate to call Hypericum perforatum the common St John's wort or perforate St John's wort.[27][1]
History
Hypericum perforatum has been known and used since at least the first century. Pedanius Dioscorides, an early pharmacologist, referred to either it or H. empetrifolium as akuron.[27] The species was first formally described by Carl Linnaeus in the second tome of Species Plantarum in 1753. In it, he gave the following brief description that would serve as the foundation for all subsequent identification of the species:[32]
Linnaeus also noted the species' habitat in the "meadows of Europe" and gave a short account of previous mentions of the plant.[32]
While Linnaeus' taxonomic priority for this species is not in question, there are a number of botanical synonyms that were published in the early years of formal botanical nomenclature. Gaterau published Description des plantes qui croissent aux environs de Montauban in 1789 which described and called the species Hypericum officinale, a name now considered to be illegitimate under the principle of priority. Likewise, the name Hypericum officinarum by Heinrich Johann Nepomuk von Crantz in 1763 also postdated Linnaeus' 1753 naming and description and is considered invalid.[33]
Subdivision
Hypericum perforatum exhibits a great deal of variability in its appearance across its distribution. Thus, determining the exact nature of its infraspecific taxa is difficult because of the many intermediate forms that exist.[34]
- H. perforatum vittaeare present throughout the plant's life cycle and are almost always narrow.
- H. perforatum variety angustifolium DC. is a variety of the species that is found in drier climates within the range of ssp. perforatum. It has leaves that look more like those of ssp. veronense, but they have leaf stalks; the glands on the seed capsule are also distinct.[34]
- H. perforatum var. humile Stranski can be found in parts of the southern Balkans. These plants possess smaller, more ring-shaped leaves and the seed capsules have flattish vesicles on their surface. These appear to be adaptations of ssp. perforatum in response to the mountainous habitats of the region.[35]
- H. perforatum ssp. songaricum is likely the most primitive after ssp. perforatum. Previously described as a variety by Karl Koch, Norman Robson elevated the taxon to subspecies in his monograph of the genus. The leaves are sessile and have a heart-shaped base that partially surrounds the stem.[35]
- H. perforatum var. gracile has smaller leaves and is found in western Kazakhstan, southern Russia, and southern Ukraine. In the drier areas of this range the variety exhibits a dull grey-green color on the underside of its leaves.[35]
- H. perforatum ssp. veronense can be found in the Caucasus, across the Middle East to Tajikistan, and along North Africa to Macaronesia. These plants have narrower leaves and display diagonal vittae on the seed capsules. Where it meets the distribution of ssp. perforatum the two subspecies hybridize regularly.[35]
- H. perforatum var. ellipticum retains the diagonal vittae of the subspecies but the leaves are not as narrow. The variety is distributed in areas with greater moisture such as in the mountainous areas of Turkmenistan.[35]
- H. perforatum ssp. chinense is found across most of China and was introduced into Japan (under the synonym H. foliosissimum Koidz.). Both its leaves and flowers are smaller, and the flower clusters are smaller and more crowded on the ends of longer branches.[35]
Ecology
H. perforatum is native to
Distribution
Hypericum perforatum is thought to be native to every nation in Europe and is only absent from the far north such as north European Russia and Svalbard. It grows in parts of North Africa and is native to Morocco, Algeria, Tunisia, and Sudan.[33]
In the Arabian Peninsula it only grows in parts of Saudi Arabia. It is present and native to all of the Western Asia phytogeographic region from the Aegean Islands and Turkey to Israel and Palestine in the west to Afghanistan in the east, only being absent from the Sinai Peninsula. Just to the east of this area it is also native to Pakistan and the western Himalaya region of India.[33]
In the temperate parts of Asia, Hypericum perforatum is mostly absent from Siberia with the exception of western Siberia, the Altai Region, and the warmest parts of Krasnoyarsk Krai. It has also been introduced to Irkutsk and Buryatiya. It is a native part of the flora of Central Asia, growing in all the former Soviet republics. It also is known in almost every part of the Caucasus. In China it is native to Xinjiang (western China), central China, and southern China, but not to Inner Mongolia, Manchuria, or Tibet. In the far east of Asia it has been introduced to
In North America it is found in all of the continental US states except for Utah, Arizona, Florida, and Alabama. It has also been introduced to the Canadian provinces of British Columbia, Manitoba, Ontario, Quebec, and the maritime provinces besides Labrador.[39] It has also been introduced to Hawaii, Cuba, and Haiti.[33]
In South America it is found in Argentina, Chile, Uruguay, the Juan Fernández Islands, and the more temperate parts of Brazil in the southeast. In the southern parts of Africa it has become established in South Africa, Lesotho, and Réunion. In Australia it is now found in the states of South Australia, Tasmania, Victoria, and Western Australia. It has also been introduced to both the North and South Islands of New Zealand.[33]
Habitat
The species can be found in a variety of habitats including open woods, meadows, grasslands, steppe, riverbanks, and stony or grassy hillsides and roadsides. It prefers dry habitats or areas with strong drainage.[34] The species thrives in areas with at least 760 mm of rainfall per year; however, its distribution is restricted by temperatures too low for seed germination or seedling survival: an absolute minimum of −3 °C or an annual average of 9 °C.[36] Altitudes greater than 1,500 metres (4,900 ft), rainfall less than 500 millimetres (20 in), and daily mean temperatures greater than 24 °C (75 °F) are also considered limiting thresholds.[40]
Reproduction
St John's wort reproduces both
Diseases
H. perforatum is affected by phytoplasma diseases, and when infected with Candidatus phytoplasma fraxini it shows visible symptoms, including yellowing and deformities called witch's broom. Its chemical profile is also altered: naphthodianthrone, flavonoid, amentoflavone, and pseudohypericin levels are reduced; chlorogenic acid levels are increased. Additionally, phytoplasma diseases greatly reduce the essential oil yield of the plant.[42]
Dieback among populations of St John's wort is also caused by fungal
Herbivores
Though Hypericum perforatum is generally avoided by mammalian herbivores, a number of insects are dependent on it and its close relatives as a food source. Chrysolina quadrigemina and C. hyperici are two beetle species that feed on plants from the genus Hypericum, including H. perforatum. Chrysolina quadrigemina can be colored metallic blue, purple, green, or bronze and is better adapted to warm and dry climates; Chrysolina hyperici is consistently smaller, metallic green, and tends to live in areas with wetter and cooler conditions.[44] Another Hyericum specialist beetle is Agrilus hyperici, the St John's wort root borer, whose larvae feed on the roots of H. perforatum while the adults feed on the foliage.[45]
A moth, Aplocera plagiata, feeds heavily upon the leaves of H. perforatum as a caterpillar and is commonly known as the common St John's wort inchworm. As adults they are a small moth with gray wings and dark gray bands.[3] Another moth that feeds upon H. perforatum is Euspilapteryx auroguttella. Their caterpillars start by mining the inside of the leaves and later roll the leaves into cigar shapes to feed in greater safety.[46][47] Agonopterix hypericella is another small (17 mm) gray moth that exclusively feeds upon Hypericum.[48][47]
Zeuxidiplosis giardi, the common St. Johnswort gall midge, is a small (3 mm) fly that eats H. perforatum while developing. The larvae feed upon leaf buds, which causes the plant to form a round growth called a gall where the developing insect can feed, is protected, and pupates into a mature adult.[3]
Toxicity
Hypericum perforatum is toxic to numerous domestic animals such as cows, sheep, and horses. When these animals come into contact with the plant, usually through grazing, they develop serious symptoms. The first signs are reddening of the skin accompanied by swelling, which is followed by necrosis and sloughing of the skin. Non-pigmented, white skin is most affected by the poisoning, such as the nose and ears of certain breeds of sheep.[49] Young animals are more susceptible to H. perforatum poisoning, and the plant is most toxic in spring (when it is the most palatable to herbivores) and retains its toxic effects when dried in hay.[50] Additionally, affected animals will become highly photosensitive, and exposure to sunlight can exacerbate their symptoms. As such, they should be moved to a dark area; administering of antihistamines or anti-inflammatory medicines may also help alleviate the symptoms.[49]
Invasiveness
Although H. perforatum is grown commercially in some regions of southeast Europe, it is listed as a
Effective herbicides for control of Hypericum perforatum include
Uses
Traditional medicine
Common St John's wort has been used in
Medical research
Antidepressant
Some studies and research reviews have supported the efficacy of St John's wort as a treatment for depression in humans.
In the United States, St John's wort is considered a
Interactions and side effects
St John's wort can interfere (in potentially life-endangering ways) with the effects of prescription and over-the-counter drugs.[53] It mainly does this by increasing CYP3A4 and CYP2C9 enzymes in the liver, leading to faster conversion of drugs.[66] The increase in these enzymes have been found to be caused by high hyperforin content; consumption of St John's wort products with minimal hyperforin causes fewer side effects and less interference.[67] However, the concentration of St John's wort's constituent chemicals (including hyperforin) can vary widely between different products,[68] and their dosage may not be properly marked on packaging.[67] In particular, St John's wort products can reduce the effectiveness of medicines like oral contraceptives, heart medications, HIV drugs, cancer medications, and some anticoagulants.[53] The most common side effects of St John's wort products are stomach pain, fatigue, and restlessness. Other more rare effects include photosensitivity and skin irritation, breakthrough bleeding when taking oral contraceptives, and decreased effectiveness of immunosuppressants in those who have had organ transplants.[68]
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- Robson N (2002). "Studies in the genus Hypericum L. (Guttiferae) 4(2). Section 9. Hypericum sensu lato (part 2): subsection 1. Hypericum series 1. Hypericum". Bulletin of the British Museum (Natural History) Botany. 32: 61–123 – via Biodiversity Heritage Library.