関: calabar bean、Physostigma

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African woody vines: calabar beans (同)genus Physostigma

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/12/23 13:48:30」(JST)

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Physostigma venenosum (the Calabar bean or ordeal bean) is the seed of a leguminous plant, a native of tropical Africa, poisonous to humans. It derives the first part of its scientific name from a curious beak-like appendage at the end of the stigma, in the centre of the flower; this appendage, though solid, was supposed to be hollow (hence the name from φῦσα, a bladder, and stigma).

Growth

The plant is a large, herbaceous, climbing perennial, with the stem woody at the base, up to 2 inches (5 cm) in diameter; it has a habit like the scarlet runner, and attains a height of about 50 feet (15 m). The flowers, resting on axillary peduncles, are large, about an inch long, grouped in pendulous, fascicled racemes pale-pink or purplish, and beautifully veined. The seed pods, which contain two or three seeds or beans, are 6 or 7 inches (15 or 18 cm) in length; and the beans are about the size of an ordinary horse bean but much thicker, with a deep chocolate-brown color.

Toxicology

Wikisource has the text of the 1911 Encyclopædia Britannica article Calabar Bean.

Calabar bean contains physostigmine, a reversible cholinesterase inhibitor alkaloid. The alkaloid physostigmine acts in effect like nerve gas,^[1] influencing communication between the nerves and muscles, and resulting in copious salivation, seizures, loss of control over the bladder and bowels, and eventually loss of control over the respiratory system, causing death by asphyxiation.^{[citation needed]}

The main antidote to Calabar bean poisoning is atropine,^{[medical citation needed]} which may often succeed; and the other measures are those usually employed to stimulate the circulation and respiration. Unfortunately, the antagonism between physostigmine and atropine is not perfect, and Sir Thomas Richard Fraser has shown that in such cases there comes a time when, if the action of the two drugs is summated, death results sooner than from either alone. Thus atropine will save life if three and a half times the fatal dose of physostigmine has been taken, but will hasten the end if four or more times the fatal dose has been ingested.^[2]^[3]

Historical uses

They constitute the E-ser-e or ordeal beans of the people of Old Calabar, being administered to persons accused of witchcraft or other crimes. In cases where the poisonous material did its deadly work, it was held at once to indicate and rightly to punish guilt; but when it was rejected by the stomach of the accused, innocence was held to be satisfactorily established. A form of dueling with the seeds is also known among the natives, in which the two opponents divide a bean, each eating one half; that quantity has been known to kill both adversaries. Although thus highly poisonous, the bean has nothing in external aspect, taste or smell to distinguish it from any harmless leguminous seed, and disastrous effects have resulted from its being incautiously left in the way of children. The beans were first introduced into Britain in the year 1840; but the plant was not accurately described until 1861, and its physiological effects were investigated in 1863 by Sir Thomas Richard Fraser. The bean usually contains a little more than 1% of alkaloids. Two of these have been identified, one called calabarine with atropine-like effects, and the other, the drug physostigmine, used in the treatment of anticholinergic syndrome, myasthenia gravis, glaucoma and delayed gastric emptying.^{[citation needed]}

References

This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.
"The killer bean of Calabar", Laura Spinney, Histories, New Scientist, 28 June 2003.
"A Modern Herbal", Maude Grieve (1931)

http://botanical.com/botanical/mgmh/c/calbea05.html

^ Colovic, MB; Krstic, Danijela Z.; Lazarevic-Pasti, Tamara D.; Bondzic, Aleksandra M.; Vasic, Vesna M. (2013). "Acetylcholinesterase Inhibitors: Pharmacology and Toxicology". Current Neuropharmacology 11 (3): 315–335. doi:10.2174/1570159X11311030006.
^ Fraser, T. R. (1867). "On the Physiological Action of the Calabar-bean (Physostigma venenosum Balf.)". Transactions of the Royal Society of Edinburgh XXIV.
^ Fraser, T. R. (1867). "On the Physiological Action of the Calabar Bean". Journal of Anatomy and Physiology 1 (2): 323–332. PMC 1318559. PMID 17230725.

English Journal

Ethnobotanical treatment strategies against Alzheimer's disease.

Howes MJ1, Houghton PJ.
Current Alzheimer research.Curr Alzheimer Res.2012 Jan;9(1):67-85.
Ethnobotany encompasses the cultural uses of plants by humans, including their uses as medicines (ethnopharmacology). The reputed medicinal properties of plants have been documented for centuries in different cultures, and there are many plant species that have been traditionally used for memory dis
PMID 22329652

The role of phytochemicals in the treatment and prevention of dementia.

Howes MJ1, Perry E.
Drugs & aging.Drugs Aging.2011 Jun 1;28(6):439-68. doi: 10.2165/11591310-000000000-00000.
Dementia pathologies such as Alzheimer's disease (AD) are reaching epidemic proportions, yet they are not successfully managed by effective symptomatic treatments. Only five drugs have been developed to alleviate cognitive symptoms, and more effective and safe treatments are needed for both the cogn
PMID 21639405

The early toxicology of physostigmine: a tale of beans, great men and egos.

Proudfoot A1.
Toxicological reviews.Toxicol Rev.2006;25(2):99-138.
Mid-19th century European visitors to Old Calabar, an eastern province of Nigeria, could not avoid becoming aware of native belief in the power of the seeds of a local plant to determine whether individuals were innocent or guilty of some serious misdemeanour. The seeds were those of a previously un
PMID 16958557

Japanese Journal

Biologically active components of Physostigma venenosum

ZHAO Bin,MOOCHHALA Shabbir M.,THAM Su-yin
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 812(1), 183-192, 2004-12-05
NAID 10016559323

ENANTIOSELECTIVE SYNTHESIS OF (-)-PHYSOSTIGMINE

高野誠一,後藤恵美子,平間道康,小笠原国郎
Chemical & pharmaceutical bulletin 30(7), 2641-2643, 1982-07-25
… The first enantioselective synthesis of (-)-physostigmine (1), a potent cholinesterase-inhibiting alkaloid from Physostigma venenosum Balf., has been accomplished using (S)-(-)-benzyl 2,3-epoxypropyl ether (5) as a chiral synthon. …
NAID 110003634656

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★リンクテーブル★

リンク元	「カラバルマメ」「calabar bean」
関連記事	「Physostigma」

「カラバルマメ」

Calabar bean
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Fabales
Family:	Fabaceae
Subfamily:	Faboideae
Genus:	Physostigma
Species:	P. venenosum
Binomial name
	Physostigma venenosum; Balf.