Aesculus hippocastanum

Life-forms

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Cladus: Rosids
Cladus: Eurosids II
Ordo: Sapindales

Familia: Sapindaceae
Subfamilia: Hippocastanoideae
Tribus: Hippocastaneae
Genus: Aesculus
Sectio: A. sect. Aesculus
Species: Aesculus hippocastanum
Name

Aesculus hippocastanum L.

Typus: LT: Herb. Clifford: 142, Aesculus No. 1 (BM)
Synonyms

Homotypic
Aesculus procera Salisb., Prodr. : 280. 1796, nom. illeg.
Aesculus septenata Stokes, Bot. Mat. Med., 2: 337. 1812, nom. illeg.
Esculus hipocastanea (L.) Raf., Fl. Med. vol. 2, 219. 1830.
Hippocastanum aesculus Cav., Descr. Pl. Lecc. Publ., 458. 1827.
Hippocastanum vulgare Gaertn., Fruct. sem. pl. vol. 2, 135, t. 3. 1791.
Pawia hippocastanum (L.) Kuntze, Revis. Gen. Pl., 1: 146. 1891.

Heterotypic
Aesculus asplenifolia Loud., Encyc. Trees, 124.
Aesculus castanea Gilib., Fl. Lit. Inch. vol. 2, 197. 1782.
Aesculus heterophylla hort. ex Handl. Trees Kew Pt. 1. (Polypet.) 83. 1894.
Aesculus ohiotensis Lindl., Bot. Reg. vol. 24, t. 51. 1838, non A. ohioensis Michx. (1810).
Aesculus hippocastanum f. beaumanii (C.K.Schneid.) Dole, Fl. Vermont (Dole), ed. 3 185. 1937.
Aesculus hippocastanum f. laciniata (Jacq.) Schelle
Aesculus hippocastanum f. pendula (Puvill.) Rehder, Bibl. Cult. Trees 430. 1949.
Aesculus hippocastanum f. pyramidalis Henry
Aesculus hippocastanum var. argenteovariegata Loudon, Arbor. Frutic. Brit. 1: 463. 1838.
Aesculus hippocastanum var. aureovariegata Loudon, Arbor. Frutic. Brit. 1: 463. 1838.
Aesculus hippocastanum var. asplenifolia hort.
Aesculus hippocastanum var. beaumanii Schneid.
Aesculus hippocastanum var. dissecta hort.
Aesculus hippocastanum var. flore-pleno Loudon, Arbor. Frutic. Brit. 1: 463. 1838.
Aesculus hippocastanum var. incisa Booth ex Loud., Encycl. Trees Shrubs 124. 1842.
Aesculus hippocastanum var. laciniata Jacq.
Aesculus hippocastanum var. pendula Puvill., Rev. Hort. n.s., 17: 281. 1921.
Aesculus hippocastanum var. pumila Dipp.
Aesculus hippocastanum var. umbraculifera Jaeg.
Aesculus hippocastanum var. variegata Loudon, Arbor. Frutic. Brit. 1: 463. 1838.
Aesculus incisa hort. ex Handl. Trees Kew Pt. 1. (Polypet.) 83. 1894.
Aesculus memmingeri C.Koch, Dendrologie 1: 506. 1869.
Aesculus procera Salisb., Prodr. Stirp. Chap. Allerton 280. 1796.
Aesculus septenata Stokes, Bot. Mat. Med. 2. 337. 1812.

Hybrids

Aesculus × carnea Hayne
Aesculus × hemiacantha Topa

References

Linnaeus, C. 1753. Species Plantarum. Tomus I: 344. Reference page.
Aesculus hippocastanum at the Euro+Med Plantbase Project
USDA, ARS, Germplasm Resources Information Network. Aesculus hippocastanum in the Germplasm Resources Information Network (GRIN), U.S. Department of Agriculture Agricultural Research Service.

Vernacular names
العربية: كستناء الحصان
беларуская: Конскі каштан звычайны
bosanski: Divlji kesten
català: Castanyer d'Índia
čeština: Jírovec maďal
dansk: Almindelig Hestekastanje
Deutsch: Gewöhnliche Rosskastanie
English: Horse-chestnut
Esperanto: Hipokastano
español: Castaño de Indias
eesti: Harilik hobukastan
suomi: Balkaninhevoskastanja
Nordfriisk: Hingstkastanje
français: Marronier commun
galego: Castiñeiro de Indias
עברית: ערמונית הסוסים
hrvatski: Divlji kesten
hornjoserbsce: Běły jěrowc
magyar: Közönséges vadgesztenye, vadgesztenye
italiano: Ippocastano, Castagno d'India
lietuvių: Paprastasis kaštonas
latviešu: Parastā zirgkastaņa
македонски: Див костен
Nederlands: Witte paardenkastanje
norsk nynorsk: Hestekastanje
norsk: Hestekastanje
occitan: Marronièr d'Índia
polski: Kasztanowiec zwyczajny, Kasztanowiec biały
português: Castanheiro-da-índia
română: Castan sălbatic
русский: Конский каштан обыкновенный
sardu: Ippocastanu
slovenčina: Pagaštan konský
slovenščina: Navadni divji kostanj
српски / srpski: Дивљи кестен
svenska: Hästkastanj
українська: Гіркокаштан звичайний
中文: 歐洲七葉樹

Aesculus hippocastanum, the horse chestnut,[1][2][3] is a species of flowering plant in the soapberry and lychee family Sapindaceae. It is a large deciduous, synoecious (hermaphroditic-flowered) tree.[4] It is also called horse-chestnut,[5] European horsechestnut,[6] buckeye,[7] and conker tree.[8] It is sometimes called Spanish chestnut.[7][9][10] This name is typically used for Castanea sativa.[11][12]
Contents

1 Description
2 Etymology
3 Distribution and habitat
4 Uses
4.1 Medical uses
4.1.1 Safety
5 Other chemicals
6 Anne Frank tree
7 Symbol of Kyiv
8 Diseases
9 Gallery
10 References

Description

Aesculus hippocastanum is a large tree, growing to about 39 metres (128 ft) tall[13]: 371  with a domed crown of stout branches; on old trees the outer branches are often pendulous with curled-up tips. The leaves are opposite and palmately compound, with 5–7 leaflets; each leaflet is 13–30 cm (5–12 in) long, making the whole leaf up to 60 cm (24 in) across, with a 7–20 cm (3–8 in) petiole. The leaf scars left on twigs after the leaves have fallen have a distinctive horseshoe shape, complete with seven "nails". The flowers are usually white with a yellow to pink blotch at the base of the petals;[13] they are produced in spring in erect panicles 10–30 cm (4–12 in) tall with about 20–50 flowers on each panicle. Its pollens are not poisonous for honey bees.[14] Usually only 1–5 fruits develop on each panicle; the shell is a green, spiky capsule containing one (rarely two or three) nut-like seeds called conkers or horse-chestnuts. Each conker is 2–4 cm (3⁄4–1+1⁄2 in) in diameter, glossy nut-brown with a whitish scar at the base.[15]
Inflorescence
Floral diagram of A. hippocastanum. The light green structure denotes nectary. Floral formula: ↘ K5 C2:2 A5+2 G(3).
Etymology

The common name horse chestnut originates from the similarity of the leaves and fruits to sweet chestnuts, Castanea sativa (a tree in a different family, the Fagaceae), together with the alleged observation that the fruit or seeds could help panting or coughing horses.[16][17]

Although it is sometimes known as buckeye,[7] for the resemblance of the seed to a deer's eye, the term buckeye is more commonly used for New World members of the genus Aesculus.[18]
Distribution and habitat

Aesculus hippocastanum is native to a small area in the Pindus Mountains mixed forests and Balkan mixed forests of South East Europe.[19] However, it can be found in many parts of Europe as far north as Gästrikland in Sweden, as well as in many parks and cities in the northern United States and Canada.
Uses

It is widely cultivated in streets and parks throughout the temperate world, and has been particularly successful in places like Ireland, Great Britain and New Zealand, where they are commonly found in parks, streets and avenues. Cultivation for its spectacular spring flowers is successful in a wide range of temperate climatic conditions provided summers are not too hot, with trees being grown as far north as Edmonton, Alberta, Canada,[20] the Faroe Islands,[21] Reykjavík, Iceland and Harstad, Norway.

In Britain and Ireland, the seeds are used for the popular children's game conkers. During the First World War, there was a campaign to ask for everyone (including children) to collect the seeds and donate them to the government. The conkers were used as a source of starch for fermentation using the Clostridium acetobutylicum method devised by Chaim Weizmann to produce acetone for use as a solvent for the production of cordite, which was then used in military armaments. Weizmann's process could use any source of starch, but the government chose to ask for conkers to avoid causing starvation by depleting food sources. But conkers were found to be a poor source, and the factory only produced acetone for three months; however, they were collected again in the Second World War for the same reason.[22] In the US state of Ohio, the seeds of the related Aesculus glabra are called 'buckeyes' and give rise to one of the state's symbols and nicknames, the Buckeye State.[23]
A selection of fresh conkers

The seeds, especially those that are young and fresh, are slightly poisonous, containing alkaloid saponins and glucosides. Although not dangerous to touch, they cause sickness when eaten; consumed by horses, they can cause tremors and lack of coordination.[24]

The horse-chestnut is a favourite subject for bonsai.[25]

Though the seeds are said to repel spiders there is little evidence to support these claims. The presence of saponin may repel insects but it is not clear whether this is effective on spiders.[26]

Aesculus hippocastanum is affected by the leaf-mining moth Cameraria ohridella, whose larvae feed on horse chestnut leaves. The moth was described from North Macedonia where the species was discovered in 1984 but took 18 years to reach Britain.[27]

In Germany, they are commonly planted in beer gardens, particularly in Bavaria. Prior to the advent of mechanical refrigeration, brewers would dig cellars for lagering. To further protect the cellars from the summer heat, they would plant chestnut trees, which have spreading, dense canopies but shallow roots which would not intrude on the caverns. The practice of serving beer at these sites evolved into the modern beer garden.[28]
Medical uses
Aescin

The seed extract standardized to around 20 percent aescin (escin) is used for its venotonic effect, vascular protection, anti-inflammatory and free radical scavenging properties.[29][30] Primary indication is chronic venous insufficiency.[30][31] A Cochrane Review suggested that horse chestnut seed extract may be an efficacious and safe short-term treatment for chronic venous insufficiency, but definitive randomized controlled trials had not been conducted to confirm the efficacy.[32]
Safety
Remainders of horse chestnut flower spikes found on the ground below. The chestnuts themselves have separated with their burs from the small branches shown.
Remainders of two horse chestnut flower spikes - one 27 cm long - with two chestnuts found on the ground under the tree. The chestnuts themselves have separated with their burs from the small branches shown.

Two preparations are considered: whole horse chestnut extract (whole HCE) and purified β-aescin. Historically, whole HCE has been used both for oral and IV routes (as of 2001). The rate of adverse effects is low; in a large German study, 0.6%, consisting mainly of gastrointestinal symptoms.[medical citation needed] Dizziness, headache and itching have been reported. One serious safety issue is rare cases of acute anaphylactic reactions, presumably in a context of whole HCE.

Another is the risk of acute kidney injury, "when patients, who had undergone cardiac surgery were given high doses of horse chestnut extract i.v. for postoperative oedema. The phenomenon was dose dependent as no alteration in kidney function was recorded with 340 μg/kg, mild kidney function impairment developed with 360 μg/kg and acute kidney injury with 510 μg/kg".[33] This almost certainly took place in a context of whole HCE.

Three clinical trials were since performed to assess the effects of aescin on kidney function. A total of 83 subjects were studied; 18 healthy volunteers given 10 or 20 mg iv. for 6 days, 40 in-patients with normal kidney function given 10 mg iv. two times per day (except two children given 0.2 mg/kg), 12 patients with cerebral oedema and normal kidney function given a massive iv. dose on the day of surgery (49.2 ± 19.3 mg) and 15.4 ± 9.4 mg daily for the following 10 days and 13 patients with impaired kidney function due to glomerulonephritis or pyelonephritis, who were given 20–25 mg iv. daily for 6 days. "In all studies renal function was monitored daily resorting to the usual tests of renal function: blood urea nitrogen (BUN), serum creatinine, creatinine clearance, urinalysis. In a selected number of cases paraaminohippurate and labelled EDTA clearance were also measured. No signs of development of renal impairment in the patients with normal renal function or of worsening of renal function in the patients with renal impairment were recorded." It is concluded that aescin has excellent tolerability in a clinical setting.[34]

Raw horse chestnut seed, leaf, bark and flower are toxic due to the presence of esculin and should not be ingested. Horse chestnut seed is classified by the FDA as an unsafe herb.[30] The glycoside and saponin constituents are considered toxic.[30]
Other chemicals

Quercetin 3,4'-diglucoside, a flavonol glycoside can also be found in horse chestnut seeds.[35] Leucocyanidin, leucodelphinidin and procyanidin A2 can also be found in horse chestnut.
Anne Frank tree

A fine specimen of the horse-chestnut was the Anne Frank tree in the centre of Amsterdam, which she mentioned in her diary and which survived until August 2010, when a heavy wind blew it over.[36][37] Eleven young specimens, sprouted from seeds from this tree, were transported to the United States. After a long quarantine in Indianapolis, each tree was shipped off to a new home at a notable museum or institution in the United States, such as the 9/11 Memorial Park, Central H.S. in Little Rock, and two Holocaust Centers. One of them was planted outdoors in March 2013 in front of the Children's Museum of Indianapolis, where they were originally quarantined.[38]
Symbol of Kyiv

The horse chestnut tree is one of the symbols of Kyiv, the capital of Ukraine.[39]
Diseases
Horse-chestnut leaf miner (Cameraria ohridella) tree damage in Parma, Italy

Bleeding canker. Half of all horse-chestnuts in Great Britain are now showing symptoms to some degree of this potentially lethal bacterial infection.[40][41]
Guignardia leaf blotch, caused by the fungus Guignardia aesculi
Wood rotting fungi, e.g. such as Armillaria and Ganoderma
Horse chestnut scale, caused by the insect Pulvinaria regalis
Horse-chestnut leaf miner, Cameraria ohridella, a leaf mining moth.[42] Also affecting large numbers of UK trees.[41]
Phytophthora bleeding canker, a fungal infection.[43]

References

Allen, D.J.; Khela, S. (2017). "Horse Chestnut, Aesculus hippocastanum" [errata version published in 2018]. IUCN Red List of Threatened Species. IUCN. 2017: e.T202914A122961065. Retrieved 27 September 2019.
USDA, NRCS (n.d.). "Aesculus hippocastanum". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 26 September 2020.
Brouillet L, Desmet P, Coursol F, Meades SJ, Favreau M, Anions M, Bélisle P, Gendreau C, Shorthouse D, et al. "Aesculus hippocastanum Linnaeus". data.canadensys.net. Database of Vascular Plants of Canada (VASCAN). Retrieved 26 September 2020.
"Aesculus hippocastanum: Reproduction". Archived from the original on 2015-01-30.
BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
"Aesculus hippocastanum (Common Horsechestnut, European Horsechestnut, Horsechestnut) | North Carolina Extension Gardener Plant Toolbox". plants.ces.ncsu.edu. Retrieved 24 March 2021.
NCCIH.nih.gov Horse Chestnut page
Coles, Jeremy. "Why we love conkers and horse chestnut trees". BBC Earth. Retrieved 23 March 2021.
Leach, M. 2001. Aesculus hippocastanum. Australian Journal of Medical Herbalism, 13(4).
"Horse Chestnut | Winchester Hospital". www.winchesterhospital.org. Retrieved 24 March 2021.
Chisholm, Hugh, ed. (1911). "Chestnut" . Encyclopædia Britannica (11th ed.). Cambridge University Press.
"Castanea sativa (European chestnut, Spanish Chestnut, Sweet chestnut) | North Carolina Extension Gardener Plant Toolbox". plants.ces.ncsu.edu. Retrieved 24 March 2021.
Stace, C. A. (2010). New Flora of the British Isles (Third ed.). Cambridge, U.K.: Cambridge University Press. ISBN 9780521707725.
Bee trees – Horse chestnut (Aesculus hippocastanum)
Rushforth, K. (1999). Trees of Britain and Europe. Collins ISBN 0-00-220013-9.
Lack, H. Walter. "The Discovery and Rediscovery of the Horse Chestnut" (PDF). Arnoldia. 61 (4).
Little, Elbert L. (1994) [1980]. The Audubon Society Field Guide to North American Trees: Western Region (Chanticleer Press ed.). Knopf. p. 541. ISBN 0394507614.
Wott, John A. "The Many Faces of Aesculus" (PDF). Washington Park Arboretum Bulletin.
"Aesculus hippocastanum". Euro+Med Plantbase Project. Archived from the original on September 28, 2007.
Edmonton
Højgaard, A., Jóhansen, J., & Ødum, S. (1989). A century of tree planting on the Faroe Islands. Ann. Soc. Sci. Faeroensis Supplementum 14.
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"Ohio State Nickname | The Buckeye State". statesymbolsusa.org. Retrieved 2021-09-08.
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D'Cruz, Mark. "Ma-Ke Bonsai Care Guide for Aesculus hippocastanum". Ma-Ke Bonsai. Archived from the original on 2012-03-15. Retrieved 2011-07-05.
Edwards, Jon (2010). "Spiders vs conkers: the definitive guide". Royal Society of Chemistry. Archived from the original on 2013-09-06. Retrieved 2013-09-09.
Lees, D.C.; Lopez-Vaamonde, C.; Augustin, S. 2009. Taxon page for Cameraria ohridella Deschka & Dimic 1986. In: EOLspecies, http://www.eol.org/pages/306084. First Created: 2009-06-22T13:47:37Z. Last Updated: 2009-08-10T12:57:23Z.
Schäffer, Albert (2012-05-21). "120 Minuten sind nicht genug" [120 minutes aren't enough]. Frankfurter Allgemeine Zeitung (in German). Retrieved 2016-10-11.
Diehm, C.; Trampisch, H. J.; Lange, S.; Schmidt, C. (1996). "Comparison of leg compression stocking and oral horse-chestnut seed extract therapy in patients with chronic venous insufficiency". Lancet. 347 (8997): 292–4. doi:10.1016/s0140-6736(96)90467-5. PMID 8569363. S2CID 20408233.
Horse Chestnut, Memorial Sloan-Kettering Cancer Center
"Horse Chestnut". National Center for Complementary and Integrative Health. May 2006. Retrieved October 24, 2019.
Pittler MH, Ernst E. (2012). "Horse chestnut seed extract for chronic venous insufficiency". Cochrane Database Syst Rev. 11: CD003230. doi:10.1002/14651858.CD003230.pub4. PMC 7144685. PMID 23152216.
Parfitt, Kathleen (1999). Martindale: The complete drug reference.: Das komplette Arzneimittelverzeichnis. pp. 1543–4. ISBN 085369429X.
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Wagner, J. (1961). "Quercetin-3,4?-diglukosid, ein Flavonolglykosid des Roßkastaniensamens". Die Naturwissenschaften. 48 (2): 54. Bibcode:1961NW.....48Q..54W. doi:10.1007/BF00603428. S2CID 29060667.
Sterling, Toby (24 August 2010). "Anne Frank's 'beautiful' tree felled by Amsterdam storm". The Scotsman. Retrieved 24 August 2010.
Gray-Block, Aaron (23 August 2010). "Anne Frank tree falls over in heavy wind, rain". Reuters. Archived from the original on 24 August 2010. Retrieved 24 August 2010.
Pamela Engel (24 March 2013). "Saplings from Anne Frank's tree take root in US". Retrieved 26 July 2018 – via Yahoo News.
"Thujoy Khreshchatyk". Why Kyivans miss chestnuts and how they became a symbol of the capital, Ukrayinska Pravda (29 May 2019) (in Ukrainian)
"Extent of the bleeding canker of horse chestnut problem". UK Forestry Commission. Archived from the original on 2009-12-09. Retrieved 2010-01-09.
"Archived copy". www.suffolkcoastal.gov.uk. Archived from the original on 23 September 2011. Retrieved 15 January 2022.
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