Hypericum

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Hypericum
Saint John's wort flowers.jpg
Hypericum perforatum
Scientific classification edit
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Malpighiales
Family: Hypericaceae
Tribe: Hypericeae
Genus: Hypericum
L.
Species

c. 490

Synonyms

Hypericum /ˌhˈprɪkəm/ is a genus of flowering plants in the family Hypericaceae (formerly considered a subfamily of Clusiaceae). Hypericum is unusual for a genus of its size because a worldwide taxonomic monograph[1] was produced for it by Norman Robson (working at the Natural History Museum, London). Robson recognizes 36 sections within Hypericum. The genus has a nearly worldwide distribution, missing only from tropical lowlands, deserts and polar regions. All members of the genus may be referred to as St. John's wort, and some are known as tutsan. The white or pink flowered marsh St. John's-worts of North American and eastern Asia are now separated into the genus Triadenum.[2]

Description[edit]

Hypericum species are quite variable in habit, occurring as trees, shrubs, annuals, and perennials. Trees in the sense of single stemmed woody plants are rare, as most woody species have multiple stems arising from a single base. Certain rarities occur in the section Camplyosporus, for example Hypericum bequaertii, growing upwards of 10 m (33 ft) from a single woody trunk. Shrubs have erect or spreading stems but never root from nodes that touch the ground. However, perennial herbs tend to root from these horizontal nodes, especially those that occur in wet habitats. Annual herbs tend to have taproots with a developed system of secondary hair roots. Many species of Hypericum are completely glabrous, others have simple uniseriate hairs, and some species have long, fine hairs.[3]

Glandular dots on a leaf of Hypericum perforatum

Two types of glands form the characteristic punctiform patterns of Hypericum, "dark glands" and "pale glands". Dark glands consist of clusters of cells with a distinct black to reddish color. Their hue is indicative of a presence of naphthodianthrone, either hypericin or pseudohypericin, or both. These glands occur in about two-thirds of Hypericum sections and are usually restricted to certain organs. When these glands are crushed, the naphthodianthrones give a red stain. Paracelsus called the red secretions "Johannes-blut" in the 16th century, linking the plant to the martyr St. John and giving rise to the English and German common names of "St. John's wort". The pale glands, forming the pellucid dots, are each a schizogenous intracellular space lined with flattened cells that secrete oils and phloroglucinol derivates, including hyperforin. The distribution of these hypericin glands dissuades generalist herbivores from feeding on the plants. When generalist insects feed on Hypericum perforatum, 30-100% more naphthodianthrones are produced, repelling the insects.[3]

The four-lined stem of Hypericum subalatum

The four thin ridges of tissue along the stems are closely to the opposite-decussate leaves of Hypericum. The ridges can be minor, just being called "ridges", or prominent, being called "wings". Terete, two-lined, and six-lined stems can occur occasionally. When a species has a tree or shrub habit, the internodes become mostly terete with age, though some trace of lines can still be detected in mature plants. The number of lines is an important distinguishing characteristic; for example, H. perforatum and Hypericum maculatum are easily confused save for H. perforatum having two lines and H. maculatum having four. The pale and dark glands are present on stems of various species, and other various species have stems without any glands. In section Hypericum, the glands are only present on stem lines, and in other sections, including Origanifolia and Hirtella , the glands are distributed across the stems.[3]

Nearly all leaves of Hypericum species are arranged opposite and decussate, an exception being section Coridium in which whorls of three to four leaves occur. The leaves lack stipules and can be sessile or shortly petiolar, though long petioles exist in sections Adenosepalum and Hypericum. Basal articulation can be present, in which case leaves are deciduous above the articulation, or absent, in which case the leaves are persistent. Some species in sections Campylosporus and Brathys have an auricle-like, reflexed leaf base, whereas true auricles only exist in sections Drosocarpium, Thasia, and Crossophyllum. Laminar venation is highly variable, being dichotomous to pinnate to densely reticulate. Leaves are typically ovoid to elongate to linear in shape. Leaves are typically shorter than the internodes. Pale or dark glands can be present on or near the leaf margin and on the main leaf surface.[3]

Typically there are four or five sepals, though in section Myriandra there are rarely three. When five sepals are present they are quincuncial, and when four sepals are present they are opposite and decussate. Sepals can be equal or unequal. Sepals can be united at their base, as seen in sections Hirtella, Taeniocarpium, and Arthrophyllum. The margins are variable, having marginal glands, teeth, or hairs. The presence or absence of dark glands on the sepals is a useful distinguishing characteristic.[3]

Yellow petals

Almost all Hypericum petals are yellow, though a range of color exists from a pale lemony hue to a deep orangish-yellow. Exceptions include the white or pinkish petals of Hypericum albiflorum var. albiflorum and H. geminiflorum. Many species have petals that are lined or tinged with red, including the deep crimson petals of H. capitatum var. capitatum. Petal lengths can be equal or unequal. The petals are mostly asymmetrical except those of sections Adenotrias and Elodes. In those two sections, sterile bodies have developed between the stamen fascicles, working as lodicules to spread the petals of the pseudotubular flower, a specialized pollination mechanism. Nearly all species have glands on their petals; only section Adenotrias has completely eglandular petals. It has been hypothesized that the intensity of red on the petals is correlated with the hypericin content of the glands, but other pigments including skyrin derivatives can create a red color.[3]

Hypericum flowers have four or five fascicles that have, in total, five to two hundred stamens. The fascicles can be free or fused in various ways, often into three apparent fascicles. In sections Myriandra, Brathys, and some of Trigynobrathys, the stamens form a ring. Though stamens are usually persistent, some are deciduous. The stamens have an anther gland on the connective tissue, varying in color from amber to black.[3]

The ovaries are three or five-merous, occasionally two-merous, with a corresponding number of free or united styles. Developing seeds are borne on axile or parietal placentae, with at least two ovules per placenta. Hypericum fruits are dissimilar to most of Hypericaceae, being capsular and dehisce from the apex. The capsule can be dry or remain fleshy when mature. The capsules have elongate or punctate glands on their surface that create various shapes and patterns. These glands are typically pale amber, though in section Drosocarpium the glands are reddish-black. Extractions of these glands in certain species yielded phloroglucinol and terpenoid derivatives, suggesting a connection between these glands and the pale glands of vegetative tissue. Seeds of Hypericum species are small and range in color from a yellowish brown to dark purplish brown. The seeds are cylindric to ellipsoid and may have narrow wings. In some seeds, a basal ridge may be present, and rarely in section Adenotrias an apical caruncle is present which attracts ants to disperse seeds. Some species have highly specific germination and survival condition requirements. For example, H. lloydii is susceptible to a fungal infection as a seedling if conditions are too moist, whereas other species including H. chapmanii can grow underwater.[3]

Taxonomy[edit]

There are over 490 species in the genus.[1] The name hypericum may derive from the Greek for "above pictures,"[4] for its use over shrines to repel evil spirits, though some have translated it as "above the heath".[4][5]

Sections[edit]

Hypericum is broken up into 36 sections, each with its own subsections and species. They include:

Ecology[edit]

Hypericum species are the only known food plants of the caterpillar of the treble-bar, a species of moth. Other Lepidoptera species whose larvae sometimes feed on Hypericum include the common emerald, the engrailed (recorded on imperforate St. John's-wort, H. maculatum), the grey pug and the setaceous Hebrew character.[6] A leaf beetle, Paria sellata, feeds on the foliage of Hypericum adpressum, while ant species Formica montana and F. subsericea decorate their nests with its bright yellow petals.[5] A small, reddish-brown weevil, Anthonomous rutilus breeds in the inflorescences of Hypericum kalmianum and H. swinkianum, the larvae developing within the fruit capsules.[5]

St. John's-worts can occur as nuisance weeds in farmland and gardens. On pastures, some can be more than a nuisance, causing debilitating photosensitivity, and sometimes abortion in livestock. The beetles Chrysolina quadrigemina, Chrysolina hyperici and the St. John's-wort Root Borer (Agrilus hyperici) like to feed on common St. John's-wort (H. perforatum) plants and have been used for biocontrol where the plant has become an invasive weed.[7]

Medical properties[edit]

Hyperforin
Hypericin
Hyperforin (left) and Hypericin (right)

Common St. John's-wort (H. perforatum) 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, a small alcoholic drink.[8] Hypericum perforatum is the most potent species and it is today grown commercially for use in herbalism and medicine.[9]

De medicina

Two main compounds found in Hypericum species have been studied in more detail: hyperforin and hypericin. As psychiatric medication, it is usually taken in pill form, but may also be consumed as a tea. Standardised preparations are commercially available and research has mainly studied alcoholic extracts and isolated compounds. Research has found a noticeable effect in many cases of light and medium clinical depression,[10] but no significant improvement of severe depression and OCD.

The red, oily extract of H. perforatum may help heal wounds.[11][12] Both hypericin and hyperforin are reported to have antibiotic properties.[13] Justifying this view with the then-current doctrine of signatures, herbalist William Coles (1626–1662)[14] 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.[15]

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.[16]

Ornamental plants[edit]

Hypericum olympicum in Botanic garden Liberec

Some species are used as ornamental plants as many have large, showy flowers. Species found in cultivation include:[17]

Numerous hybrids and cultivars have been developed for use in horticulture, such as H. × moserianum[18] (H. calycinum × H. patulum), H. 'Hidcote'[19] and H. 'Rowallane'.[20] All of the above cultivars have gained the Royal Horticultural Society's Award of Garden Merit.[18][19][20][21]

Most species of Hypericum are prone to thrips, scale, anthracnose, rust, and leaf spots.[22] They are also eaten or infected by aphids, white flies, and spodoptera littoralis.[23]

Fossil record[edit]

Fossil seeds from the early Miocene of †Hypericum septestum have been found in the Czech part of the Zittau Basin.[24] Many fossil seeds of †Hypericum holyi have been described from middle Miocene strata of the Fasterholt area near Silkeborg in Central Jutland, Denmark.[25]

See also[edit]

References[edit]

  1. ^ a b Hypericum Online
  2. ^ Missouri Botanical Garden Retrieved November 23, 2015
  3. ^ a b c d e f g h Robson, Norman K. B.; Crocket, Sara L. (2011). "Taxonomy and chemotaxonomy of the genus Hypericum" (PDF). Medicinal and aromatic plant science and biotechnology. Europe PMC Funders. 5 (Special Issue 1): 1.
  4. ^ a b Gledhill, David (2008). The Names of Plants, 4th edition. Cambridge University Press. p. 208. ISBN 978-0-521-86645-3.
  5. ^ a b c Wilhelm, Gerould; Rericha, Laura (2017). Flora of the Chicago Region: A Floristic and Ecological Synthesis. Indiana Academy of Sciences.
  6. ^ "HOSTS-Search Results". HOSTS. Natural History Museum, London. Retrieved 18 February 2016.
  7. ^ "Ecology and Management of Common St. Johnswort | NRCS Montana". www.nrcs.usda.gov. Retrieved 2016-02-19.
  8. ^ Fine Gardening retrieved November 23, 2015
  9. ^ USDA.gov Retrieved November 23, 2015
  10. ^ Szegedi, A; Kohnen, R; Dienel, A; Kieser, M (2005). "Acute treatment of moderate to severe depression with hypericum extract WS 5570 (St John's wort): Randomised controlled double blind non-inferiority trial versus paroxetine". BMJ. 330 (7490): 503. doi:10.1136/bmj.38356.655266.82. PMC 552808. PMID 15708844.
  11. ^ Samadi, S; Khadivzadeh, T; Emami, A; Moosavi, NS; Tafaghodi, M; Behnam, HR (2010). "The effect of Hypericum perforatum on the wound healing and scar of cesarean". Journal of alternative and complementary medicine. 16 (1): 113–7. doi:10.1089/acm.2009.0317. PMID 20064022.
  12. ^ Süntar, Ipek Peşin; Akkol, Esra Küpeli; Yılmazer, Demet; Baykal, Turhan; Kırmızıbekmez, Hasan; Alper, Murat; Yeşilada, Erdem (2010). "Investigations on the in vivo wound healing potential of Hypericum perforatum L". Journal of Ethnopharmacology. 127 (2): 468–77. doi:10.1016/j.jep.2009.10.011. PMID 19833187.
  13. ^ Schempp, Christoph M; Pelz, Klaus; Wittmer, Annette; Schöpf, Erwin; Simon, Jan C (1999). "Antibacterial activity of hyperforin from St John's wort, against multiresistant Staphylococcus aureus and gram-positive bacteria". The Lancet. 353 (9170): 2129. doi:10.1016/S0140-6736(99)00214-7. PMID 10382704.
  14. ^ Coles, William (1657). Adam in Eden, or, Natures paradise. OCLC 217197164.[page needed]
  15. ^ Subhan, F; Khan, N; Sewell, RD (2009). "Adulterant profile of illicit street heroin and reduction of its precipitated physical dependence withdrawal syndrome by extracts of St John's wort (Hypericum perforatum)". Phytotherapy Research. 23 (4): 564–71. doi:10.1002/ptr.2692. PMID 19067385.
  16. ^ Caraci, F; Crupi, R; Drago, F; Spina, E (2011). "Metabolic drug interactions between antidepressants and anticancer drugs: Focus on selective serotonin reuptake inhibitors and hypericum extract". Current Drug Metabolism. 12 (6): 570–7. doi:10.2174/138920011795713706. PMID 21395523.
  17. ^ Brickell, Christopher, ed. (2008). The Royal Horticultural Society A-Z Encyclopedia of Garden Plants. United Kingdom: Dorling Kindersley. p. 302. ISBN 9781405332965.
  18. ^ a b "Hypericum × moserianum". Royal Horticultural Society. Retrieved 19 May 2013.
  19. ^ a b "Hypericum × hidcoteense 'Hidcote'". Royal Horticultural Society. Retrieved 19 May 2013.
  20. ^ a b "Hypericum 'Rowallane'". Royal Horticultural Society. Retrieved 19 May 2013.
  21. ^ "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 52. Retrieved 3 March 2018.
  22. ^ Fine Gardening Retrieved November 23, 2015.
  23. ^ Dan Ziger Corporation Retrieved November 30, 2015.
  24. ^ Acta Palaeobotanica - 43(1): 9-49, January 2003 - Early Miocene carpological material from the Czech part of the Zittau Basin - Vasilis Teodoridis
  25. ^ Angiosperm Fruits and Seeds from the Middle Miocene of Jutland (Denmark) by Else Marie Friis, The Royal Danish Academy of Sciences and Letters 24:3, 1985

External links[edit]