Symphytum officinale

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Symphytum officinale
Symphytum officinale 01.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Boraginales
Family: Boraginaceae
Genus: Symphytum
Species:
S. officinale
Binomial name
Symphytum officinale
L.
Synonyms
  • Symphitum officinale(orth.var.)

Symphytum officinale is a perennial flowering plant in the family Boraginaceae. Along with thirty four other species of Symphytum, it is known as comfrey. To differentiate it from other members of the genus Symphytum, this species is known as common comfrey [1] or true comfrey. Other English names include boneset, knitbone, consound, and slippery-root. [2] It is native to Europe, growing in damp, grassy places. It is locally frequent throughout Ireland and Britain on river banks and ditches. It occurs elsewhere, including North America, as an introduced species and sometimes a weed. The flowers are mostly visited by bumblebees. [3] Internal or long-term topical use of comfrey is discouraged due to its strong potential to cause liver toxicity. [4]

Contents

History

Over centuries, comfrey was cultivated in Asia, Europe, and the United Kingdom as a vegetable and herbal medicine. [4] [5] [6] Its early common names, knitbone or boneset, reflect its historical use by poultices of leaves and roots to treat sprains, bruises or bone fractures. [4] [5] Also the roots could be mashed then packed around a broken limb, when dried they formed a hardened 'plaster cast'. [7]

Description and botany

Comfrey is found in moist grasslands or along riverbanks and ditches in western Asia, Europe, and North America. [6] It is a perennial herb that is cold hardy down to −35 °C (−31 °F) and drought-tolerant. The plant can grow 1–5 feet (0.3–1.5 m) tall [8] with branched, strongly winged stems. The root system has a pronounced, deep-reaching (up to 1.8 metres [9] ) taproot. The internally white roots are covered with black bark. Above ground the plant is covered in long, downward-pointing, tapering hairs that are bristly on the stems and softer on the leaves. Along the erect stems grow large simple, mostly stalked leaves in an alternate pattern. They are oval-lanceolate and 4 to 25 centimetres long. In the upper parts they are narrower, without stalks, and with margins that extend down the stems. The chromosome count is 2n = 24, 26, 36, 40, 48 or 54. [9]

Inflorescence and fruit

The plant flowers from May to June with forked cymes that are initially coiled and later open out. [7] They bear two rows of hermaphrodite flowers on nodding stalks that are 2 to 6 millimetres long. [10] The small flowers measure 8–20 millimetres in length and 12 to 18 millimetres across the corolla. The flowers are radially symmetrical with five equal petals that are fused into a tubular or narrowly bell-shaped corolla with pointed, recurved teeth that are 2 millimetres long. Petals come in mainly two colours – typically cream to yellow or pink to purplish. Inside are 5 stamens and 1 stigma. The calyx has a tubular segment of about 2 millimetres and narrow, pointed teeth of about 4 millimetres. The fruits are segmented into 4 egg-shaped, shiny black nutlets that are 5–6 millimetres long. The plant produces significant nectar when compared to other UK plants tested. [11] Although, it has a long tube, meaning only insects with long tongues can reach the nectar, some bees have been known to bite into the side of the flower to access the nectar – a foraging behaviour known as nectar robbing. [7]

Species differentiation

With S. × uplandicum, leaf bases are not decurrent, stem internodes are not winged, and the surfaces of the seeds are brown, dull, and finely granular instead of shiny black. [12] Additionally, Symphytum × uplandicum is generally more bristly, flowers later (between June and August), [7] and its flowers tend to be more blue or violet. [13]

Taxonomy

The latin name epithet officinale refers to its use for medicinal preparations. The official first formal scientific species description appeared in 1753 in Species Plantarum by Carl Linnaeus, Tomus I, page 136. [14]

Subspecies include subsp. uliginosum (A. Kern.) Nyman (syn. S. uliginosum auct. non Kern., S. tanaicense), subsp. officinale, and subsp. bohemicum (F. W. Schmidt) Čelak (syn. S. bohemicum).

A common hybrid is formed between Symphytum officinale and S. asperum , Symphytum × uplandicum, also known as Blue Comfrey, [7] or Russian comfrey, which is widespread in the British Isles, interbreeds with S. officinale, and represents the economically most important kind of comfrey. [15]

Traditional medicine

In folklore, Symphytum officinale roots were used in traditional medicine internally (as a herbal tea or tincture) or externally (as ointment, compresses, or alcoholic extract) for treatment of various disorders. [4] [6] [16] John Gerard, an English herbalist (1545–1612), mentions "the slimie substance of the roote made in a possett of ale" would help back pains.[ citation needed ] Poultices may be used with the intent to heal broken bones, giving it the name "knitbone". [4]

A 2013 review of clinical studies assessing the possible effect of comfrey on osteoarthritis found the research quality was too low to allow conclusions about its efficacy and safety. [17] In Europe as of 2015, there were no comfrey products for oral use, and those for topical uses to treat bruises or joint pain were evaluated as having risk of liver toxicity. [5]

Toxicity and adverse effects

Comfrey is mildly toxic. Like most Boraginaceae, it contains pyrrolizidine alkaloids which are toxic compounds readily absorbed via the stomach or skin, and have potential to increase the risk of fatal liver toxicity. [4] [5] [18] In 2001, the US Food and Drug Administration and Federal Trade Commission banned the sale of comfrey products for internal use and use on open wounds due to its potential toxicities. [19] [20] A 2018 review on pyrrolizidine alkaloids present in comfrey indicated widespread potential toxicity to humans and livestock, and the opportunity for drug development from these compounds. [21]

Related Research Articles

<span class="mw-page-title-main">Herbal tea</span> Beverage made from infusing or decocting plant material in hot water

Herbal teas, also known as herbal infusions and less commonly called tisanes, are beverages made from the infusion or decoction of herbs, spices, or other plant material in hot water. Oftentimes herb tea, or the plain term tea, is used as a reference to all sorts of herbal teas. Many herbs used in teas/tisanes are also used in herbal medicine. Some herbal blends contain actual tea.

<i>Jacobaea vulgaris</i> Flowering plant, daisy family Asteraceae

Jacobaea vulgaris, syn. Senecio jacobaea, is a very common wild flower in the family Asteraceae that is native to northern Eurasia, usually in dry, open places, and has also been widely distributed as a weed elsewhere.

<i>Symphytum</i> Genus of flowering plants in the borage family Boraginaceae

Symphytum is a genus of flowering plants in the borage family, Boraginaceae, known by the common name comfrey. There are 59 recognized species. Some species and hybrids, particularly S. officinale, Symphytum grandiflorum, and S. × uplandicum, are used in gardening and herbal medicine. They are not to be confused with Andersonglossum virginianum, known as wild comfrey, another member of the borage family.

<span class="mw-page-title-main">Borage</span> Species of flowering plant in the family Boraginaceae

Borage, also known as starflower, is an annual herb in the flowering plant family Boraginaceae native to the Mediterranean region. Although the plant contains small amounts of pyrrolizidine alkaloids, some parts are edible and its seeds provide oil.

<i>Tussilago</i> Species of flowering plant in the daisy family Asteraceae

Tussilago farfara, commonly known as coltsfoot, is a plant in the tribe Senecioneae in the family Asteraceae, native to Europe and parts of western and central Asia. The name "tussilago" is derived from the Latin tussis, meaning cough, and ago, meaning to cast or to act on. It has had uses in traditional medicine, but the discovery of toxic pyrrolizidine alkaloids in the plant has resulted in liver health concerns.

<i>Petasites hybridus</i> Species of flowering plant in the daisy family Asteraceae

Petasites hybridus, also known as the butterbur, is a herbaceous perennial flowering plant in the family Asteraceae that is native to Europe and northern Asia.

<i>Iris pseudacorus</i> Species of flowering plant in the iris family Iridaceae

Iris pseudacorus, the yellow flag, yellow iris, or water flag, is a species of flowering plant in the family Iridaceae. It is native to Europe, western Asia and northwest Africa. Its specific epithet pseudacorus means "false acorus", referring to the similarity of its leaves to those of Acorus calamus, as they have a prominently veined mid-rib and sword-like shape. However, the two plants are not closely related. The flower is commonly attributed with the fleur-de-lis.

<i>Lithospermum officinale</i> Species of flowering plant in the borage family Boraginaceae

Lithospermum officinale, or common gromwell or European stoneseed, is a flowering plant species in the family Boraginaceae, native to Eurasia. It is the host plant for caterpillars of the monophagous moth Ethmia dodecea.

<i>Sambucus canadensis</i> Species of plant

Sambucus canadensis, the American black elderberry, Canada elderberry, or common elderberry, is a species of elderberry native to a large area of North America east of the Rocky Mountains, south to Bolivia. It grows in a variety of conditions including both wet and dry soils, primarily in sunny locations.

<i>Veratrum</i> Genus of plants

Veratrum is a genus of flowering plants in the family Melanthiaceae. It occurs in damp habitats across much of temperate and subarctic Europe, Asia, and North America.

<i>Eupatorium cannabinum</i> Species of plant

Eupatorium cannabinum, commonly known as hemp-agrimony, or holy rope, is a herbaceous plant in the family Asteraceae. It is a robust perennial native to Europe, NW. Africa, Turkey, Syria, Iran, Iraq, Jordan, the Caucasus and Central Asia. It is cultivated as an ornamental and occasionally found as a garden escape in scattered locations in China, the United States and Canada. It is extremely attractive to butterflies, much like buddleia.

<span class="mw-page-title-main">Pyrrolizidine alkaloid</span> Class of chemical compounds

Pyrrolizidine alkaloids (PAs), sometimes referred to as necine bases, are a group of naturally occurring alkaloids based on the structure of pyrrolizidine. Pyrrolizidine alkaloids are produced by plants as a defense mechanism against insect herbivores. More than 660 PAs and PA N-oxides have been identified in over 6,000 plants, and about half of them exhibit hepatotoxicity. They are found frequently in plants in the Boraginaceae, Asteraceae, Orchidaceae and Fabaceae families; less frequently in the Convolvulaceae and Poaceae, and in at least one species in the Lamiaceae. It has been estimated that 3% of the world’s flowering plants contain pyrrolizidine alkaloids. Honey can contain pyrrolizidine alkaloids, as can grains, milk, offal and eggs. To date (2011), there is no international regulation of PAs in food, unlike those for herbs and medicines.

<i>Ageratum conyzoides</i> Species of plant

Ageratum conyzoides is native to Tropical America, especially Brazil, and is an invasive weed in many other regions. It is an herb that is 0.5–1 m. high, with ovate leaves 2–6 cm long, and flowers are white to mauve.

<i>Cynoglossum officinale</i> Species of flowering plant

Cynoglossum officinale is a herbaceous plant of the family Boraginaceae.

<i>Symphytum tuberosum</i> Species of plant

Symphytum tuberosum, the tuberous comfrey, is a species of Symphytum in the family Boraginaceae.

<span class="mw-page-title-main">Senecionine</span> Chemical compound

Senecionine is a toxic pyrrolizidine alkaloid isolated from various botanical sources. It takes its name from the Senecio genus and is produced by many different plants in that genus, including Jacobaea vulgaris. It has also been isolated from several other plants, including Brachyglottis repanda, Emilia, Erechtites hieraciifolius, Petasites, Syneilesis, Crotalaria, Caltha leptosepala, and Castilleja.

<i>Symphytum <span style="font-style:normal;">×</span> uplandicum</i>

Russian comfrey or Quaker comfrey is a common hybrid between Symphytum officinale and S. asperum. It represents the economically most important kind of comfrey.

<span class="mw-page-title-main">Riddelliine</span> Chemical compound

Riddelliine is a chemical compound classified as a pyrrolizidine alkaloid. It was first isolated from Senecio riddellii and is also found in a variety of plants including Jacobaea vulgaris, Senecio vulgaris, and others plants in the genus Senecio.

<i>Andersonglossum virginianum</i> Species of flowering plant

Andersonglossum virginianum, known as southern wild comfrey, is a flowering plant in the borage family native to North America. It is also sometimes called blue houndstongue.

<i>Symphytum grandiflorum</i> Species of plant in the family Boraginaceae

Symphytum grandiflorum, the creeping comfrey, or running comfrey is a species of flowering plant in the family Boraginaceae. It is native to the Caucasus region, and introduced to various locales in Europe as a garden escapee. A deer-tolerant perennial, it is hardy in USDA zones 5 through 8, and is recommended for borders and shady situations. The unimproved species and a number of cultivars are commercially available. Also, it has been crossed with Russian comfrey to produce the multi-cross hybrid Hidcote comfrey, of which a range of ornamental cultivars are available.

References

  1. ↑ USDA, NRCS (n.d.). "Symphytum officinale". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 7 December 2015.
  2. ↑ "Symphytum officinale". Germplasm Resources Information Network . Agricultural Research Service, United States Department of Agriculture . Retrieved 1 January 2018.
  3. ↑ Van Der Kooi, Casper J.; Pen, I.; Staal, M.; Stavenga, D. G.; Elzenga, J. T. M. (2015). "Competition for pollinators and intra-communal spectral dissimilarity of flowers". Plant Biology. 18 (1): 56–62. doi:10.1111/plb.12328. PMID   25754608.
  4. 1 2 3 4 5 6 "Comfrey". Drugs.com. 2018. Retrieved 16 January 2019.
  5. 1 2 3 4 "Assessment report on Symphytum officinale L., radix" (PDF). European Medicines Agency. 5 May 2015. Retrieved 16 January 2019.
  6. 1 2 3 "Symphytum officinale". Plant Finder, Missouri Botanical Garden. Retrieved 16 January 2019.
  7. 1 2 3 4 5 Reader's Digest Field Guide to the Wild Flowers of Britain. Reader's Digest. 1981. p. 242. ISBN   9780276002175.
  8. ↑ Poland, John; Clement, E. J. (2009). The Vegetative Key to the British Flora. Young Writers. p. 161. ISBN   978-0-9560144-0-5.
  9. 1 2 Erich Oberdorfer (2001). Pflanzensoziologische Exkursionsflora für Deutschland und angrenzende Gebiete (in German) (8 ed.). pp. 787–788. ISBN   3800131315.
  10. ↑ Symphytum officinale L. s. l., Arznei-Beinwell. In: FloraWeb.de.
  11. ↑ "Which flowers are the best source of nectar?". Conservation Grade. 2014-10-15. Retrieved 2017-10-18.
  12. ↑ https://ucjeps.berkeley.edu/eflora/eflora_keys.php?key=8767
  13. ↑ Stace, Clive (2010). New Flora of the British Isles (3rd ed.). Cambridge, UK: Cambridge University Press. p. 557. ISBN   978-0-521-70772-5.
  14. ↑ "Symphytum officinale". Tropicos . Missouri Botanical Garden. 4000088.
  15. ↑ Hills, Lawrence D. (2011-10-20). Comfrey: Past, Present and Future. Faber & Faber. ISBN   978-0-571-28091-9.
  16. ↑ Vogl, Sylvia; Picker, Paolo; Mihaly-Bison, Judit; Fakhrudin, Nanang; Atanasov, Atanas G.; Heiss, Elke H.; Wawrosch, Christoph; Reznicek, Gottfried; Dirsch, Verena M.; Saukel, Johannes; Kopp, Brigitte (2013). "Ethnopharmacological in vitro studies on Austria's folk medicine—An unexplored lore in vitro anti-inflammatory activities of 71 Austrian traditional herbal drugs". Journal of Ethnopharmacology. 149 (3): 750–71. doi:10.1016/j.jep.2013.06.007. PMC   3791396 . PMID   23770053.
  17. ↑ Cameron, M.; Chrubasik, S. (31 May 2013). "Topical herbal therapies for treating osteoarthritis". The Cochrane Database of Systematic Reviews. 5 (5): CD010538. doi:10.1002/14651858.CD010538. PMC   4105203 . PMID   23728701.
  18. ↑ Oberlies, Nicholas H.; Kim, Nam-Cheol; Brine, Dolores R.; Collins, Bradley J; Handy, Robert W.; Sparacino, Charles M.; Wani, Mansukh C.; Wall, Monroe E. (2007). "Analysis of herbal teas made from the leaves of comfrey (Symphytum officinale): Reduction of N-oxides results in order of magnitude increases in the measurable concentration of pyrrolizidine alkaloids". Public Health Nutrition. 7 (7): 919–24. doi: 10.1079/phn2004624 . PMID   15482618.
  19. ↑ "FDA Advises Dietary Supplement Manufacturers to Remove Comfrey Products From the Market". US Food and Drug Administration. 6 July 2001. Archived from the original on 14 November 2017. Retrieved 16 January 2019.
  20. ↑ "FTC Announces a Second Case Focusing on Safety Risks of Comfrey Products Promoted via Internet". US Federal Trade Commission. 13 July 2001. Retrieved 16 January 2019.
  21. ↑ Moreira, Rute; Pereira, David; Valentão, Patrícia; Andrade, Paula (5 June 2018). "Pyrrolizidine Alkaloids: Chemistry, Pharmacology, Toxicology and Food Safety". International Journal of Molecular Sciences. 19 (6): 1668. doi: 10.3390/ijms19061668 . ISSN   1422-0067. PMC   6032134 . PMID   29874826.
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