Symphytum is a genus of flowering plants in the borage family, Boraginaceae, known by the common name comfrey (pronounced /ˈkʌmfri/, from the Latin confervere to 'heal' or literally to 'boil together', referring to uses in ancient traditional medicine).

Symphytum
Symphytum caucasicum
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Boraginales
Family: Boraginaceae
Subfamily: Boraginoideae
Genus: Symphytum
Tourn. ex L. (1753)
Type species
Symphytum officinale
L.
Species[1]

27; see text

Synonyms[1]
  • Consolida Riv. ex Ruppius (1745), not validly publ.
  • Procopiania Guşul. (1928)
  • × Procopiphytum Pawł. (1971)

Symphytum is native to northern temperate regions of Asia and North America, with a wide introduced distribution on both continents.[2] There are 59 recognized species.[2] Some species and hybrids, particularly S. officinale, Symphytum grandiflorum, and S. × uplandicum, are used in gardening and herbal medicine. Species in the genus Symphytum are different from Andersonglossum virginianum, known as wild comfrey, which is another member of the borage family.[3]

Species

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27 species are accepted.[1]

 
Russian comfrey (Symphytum × uplandicum)
 
Flowers of Russian comfrey

Cultivation

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The Russian comfrey 'Bocking 14' cultivar was developed during the 1950s by Lawrence D. Hills, the founder of the Henry Doubleday Research Association (the organic gardening organization itself named after Henry Doubleday, who first introduced Russian comfrey into Britain in the nineteenth century) following trials at Bocking, Essex.[citation needed]

Propagation

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Bocking 14 is sterile, and therefore will not set seed (one of its advantages over other cultivars as it will not spread out of control); thus, it is propagated from root cuttings. The gardener can produce "offsets" from mature, strongly growing plants by driving a spade horizontally through the leaf clumps about 7 cm (2.8 in) below the soil surface. This removes the crown, which can then be split into pieces. The original plant will quickly recover, and each piece can be replanted with the growing points just below the soil surface, and will quickly grow into new plants. Offsets can also be purchased by mail order from specialist nurseries in order to initially build up a stock of plants.[5]

Phytochemistry, folk medicine, and toxicity

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Folk medicine names for comfrey include knitbone, boneset, and the derivation of its Latin name Symphytum (from the Greek symphis, meaning growing together of bones, and phyton, a plant), referring to its ancient uses. Similarly, the common French name is consoude, meaning to weld together. The tradition in different cultures and languages suggest a common belief in its usefulness for mending bones.

Comfrey contains mixed phytochemicals in varying amounts, including allantoin, mucilage, saponins, tannins, pyrrolizidine alkaloids, and inulin, among others.[6] Pyrrolizidine alkaloids are responsible for comfrey's liver toxicity,[7] which is associated with consuming this plant or its extracts.[6] In modern herbalism, comfrey is most commonly used topically.[6][8][9]

In 2001, the United States Food and Drug Administration issued a ban of comfrey products marketed for internal use, and a warning label for those intended for external use.[10] Use of comfrey is particularly discouraged during pregnancy and lactation, in infants, and in people with liver, kidney, or vascular diseases.[6][11]

References

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  1. ^ a b c Symphytum Tourn. ex L. Plants of the World Online. Retrieved 31 July 2024.
  2. ^ a b "Symphytum L." The World Flora Online. 18 July 2023. Retrieved 15 June 2024.
  3. ^ NRCS. "Cynoglossum virginianum". PLANTS Database. United States Department of Agriculture (USDA). Retrieved 2018-11-20.
  4. ^ "Symphytum ibericum". rhs.org.uk. Retrieved 23 April 2017.
  5. ^ Teynor TM, Putnam DH, Doll JD, Kelling KA, Oelke EA, Undersander DJ, Oplinger ES (February 1992). "Comfrey". Alternative Field Crops Manual. University of Wisconsin, Extension, Cooperative-Extension. Retrieved 25 March 2014.
  6. ^ a b c d "Comfrey". Drugs.com. 17 July 2017. Retrieved 22 May 2018.
  7. ^ Mei, Nan; Guo, Lei; Fu, Peter P.; Fuscoe, James C.; Luan, Yang; Chen, Tao (October 2010). "Metabolism, genotoxicity, and carcinogenicity of Comfrey". Journal of Toxicology and Environmental Health Part B: Critical Reviews. 13 (7–8): 509–526. Bibcode:2010JTEHB..13..509M. doi:10.1080/10937404.2010.509013. PMC 5894094. PMID 21170807.
  8. ^ Grant, G; Nolan, M; Ellis, N (July 1990). "A reappraisal of the Malaise Inventory". Social Psychiatry and Psychiatric Epidemiology. 25 (4): 170–8. doi:10.1007/BF00782957. PMC 2399473. PMID 2399473.
  9. ^ Miller, Lucinda G. (9 November 1998). "Herbal Medicinals: Selected Clinical Considerations Focusing on Known or Potential Drug-Herb Interactions". Archives of Internal Medicine. 158 (20): 2200–2211. doi:10.1001/archinte.158.20.2200. PMID 9818800.
  10. ^ "FDA/CFSAN – FDA Advises Dietary Supplement Manufacturers to Remove Comfrey Products From the Market (archived copy)". Food and Drug Administration. Retrieved 2023-06-12.
  11. ^ Yeong, Mee Ling; Swinburn, Boyd; Kennedy, Mark; Nicholson, Gordon (March 1990). "Hepatic veno-occlusive disease associated with comfrey ingestion". Journal of Gastroenterology and Hepatology. 5 (2): 211–214. doi:10.1111/j.1440-1746.1990.tb01827.x. PMID 2103401. S2CID 42511497.