Calabar Bean
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Calabar Bean ( Physostigma venenosum ) |
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The calabar bean , also known as God's judgment bean ( Physostigma venenosum ), is a species of plant in the subfamily of the butterflies (Faboideae). It is native to West Africa and is primarily known for its toxicity.
Description and ecology
Calabar beans are perennial climbing plants with a woody trunk ( lianas ) that can reach a length of up to 15 meters. The trunk diameter is up to 5 centimeters.
The leaves are unpaired, pinnate in three parts. The leaf blades are ovate and pointed.
The lateral, stalked, drooping racemose inflorescences are up to 2.5 inches long. The inflorescence rhachis is covered with nodular nodes. The bracts fall off at an early stage of the anthesis .
The typical butterfly flowers are rolled up like a snail. The cap and wings of the flowers are dark purple in color. The flag is folded, bent back and lighter in color. The shuttle and wings are almost completely covered by the flag. The tip of the shuttle is twisted in a spiral.
The pistil has a stalked ovary with a slender stylus that is curved with the shuttle. It has a beard-like hair on the inside. The only carpel is stalked. The stylus has a widened, triangular, wing-like extension behind the scar .
The thick, brown legumes are up to 15 centimeters long. Each fruit contains two or three seeds . The deep chocolate brown seeds are about 2.5 centimeters long and slightly kidney-shaped with rounded ends. The surface is rough but at least partially shiny. A scar remains where the seed had attached to the placenta .
The fruits float and the spread of the diaspores takes place so hydrochor .
Occurrence
It is in a small area on the Gulf of Guinea and in the delta of the Calabar River , in the state of Cross River in Nigeria , endemic . For example, it is a neophyte in India and Brazil .
The calabar grows on river banks, often even in shallow water, in the tropical rainforest , where it grows on trees.
Ingredients of the seeds
The seeds of the calabar bean are very poisonous. The toxins are found exclusively in the seeds and there almost exclusively in the cotyledons . All other parts of the plant are non-toxic.
The main active ingredients of the seeds are: 0.3–0.5% alkaloids with 0.15% physostigmine , geneserin , as main and minor alkaloids eseramin , and physovenin .
The component previously called calaborin is a mixture of cleavage products. An identity with isophysostigmine could not be confirmed, but the two secondary alkaloids calabatin and calabacin were identified.
Symptoms of poisoning: The effect of the calabar beans is based on their alkaloids content. Physostigmine and Physovenin inhibit acetylcholinesterase , while Geneserin and Eseramin are ineffective.
After an excessive dose of physostigmine was injected into the conjunctival sac, severe malaise, sweating, trembling of the limbs and accelerated heart activity occurred. The next day the symptoms had subsided, but further consequences were inflammation and catarrh of the entire airways, membranes on the conjunctiva of both eyes and on the larynx, and corresponding hoarseness appeared.
Poisoning with physostigmine is seldom known, but poisoning by injection with physostigmine sulfate has been described. A few minutes after the injection was given, there were cramps in the arms and legs and muscle twitches in the face. In the course of a few more minutes the patient turned blue, breathing became weaker and weaker, and half an hour after the injection, breathing and heart activity ceased completely.
The seeds of the calabar bean contain starch (48 percent), mucilage , proteins (23 percent), fats (2.3 percent) and salts (mainly potash ).
The seeds contain a little more than 1 percent of alkaloids . The indole alkaloid physostigmine, which Julius Jobst and Oswald Hesse isolated from a calabar bean in 1864, is important. A year later in 1865, Amedee Vee and Manuel Leven isolated the substance independently and named it Eserin .
Erich Harnack and Ludwig Witkowski discovered a second alkaloid in the calabar bean in 1876 and named it calabrin . Calabrin is not unlike strychnine . These two poisons are found exclusively in the seeds of the plant and there almost exclusively in the cotyledons .
use
Calabar bean extracts have been used in ophthalmology as a miotic to constrict pupils. In European medicine it was first mentioned as a miotic in 1855. Physostigmine is also an effective antidote for atropine poisoning.
Calabar beans have also been used as a cholinergic ( parasympathomimetic ) because physostigmine acts as an acetylcholinesterase inhibitor.
Cultural history
The first European to get hold of calabar beans was William Freeman Daniell in 1846 . Previously, the beans were kept as a secret by the natives and not given to whites. The respective king or tribal leader had the monopoly on the beans. Wild specimens were uprooted and the beans were very expensive.
The beans were mainly used by the Efik , but apparently also traded, as there are reports of similar rituals with calabar beans from northern Nigeria. The bean was given to suspected criminals to bring about a divine judgment . About half of the people died very quickly from the semen, which was taken as evidence of the person's guilt. However, if the delinquent vomited, choked out the semen and survived, he was considered innocent. If he did not vomit, only got diarrhea and survived, he was considered guilty and was sold as a slave .
The mere threat of this form of divine judgment was so deterring that the accused often, even if they were innocent, preferred to confess and make amends.
Similar rituals are known from Madagascar , where the poisonous nut fruit of Tanghinia venenata was used. There was also a comparable rite in Sierra Leone . A poisonous tea made from the bark of Erythrophlaeum guineense was used here.
Another use of the calabars was in a form of duel . A seed was cut in half and eaten by both participants. Not infrequently, however, both opponents died.
Systematics
Physostigma venenosum was first described by John Hutton Balfour in 1860 . It is the type species of the genus Physostigma .
etymology
The scientific name of the species venenosum comes from the Latin and means poisonous. The generic name Physostigma is composed of the ancient Greek φυσα ( phýsa ) = bladder and στιγμα ( stígma ) = scar, which is due to the wing-like extension behind the scar , which is pronounced like a bubble in some species of the genus.
The common name calabar bean takes its name from its location on the Calabar River . This type is also called God's judgment bean, which is based on the cultural and historical rituals.
swell
Unless otherwise stated, the information in the Description chapter is taken from the sources: Lloyd 1897 and Felter & Lloyd 1898. For the chapter Ingredients of the seeds, Felter & Lloyd 1898 was the main source, unless otherwise stated. For the chapter on cultural history, Lloyd 1897 was again used, unless otherwise stated.
literature
- John Uri Lloyd: Physostigma venenosum (Calabar) . In: The Western Druggist . Chicago June 1897 (English, pdf ).
- Harvey Wickes Felter, John Uri Lloyd: Physostigma . In: King's American Dispensatory . 18th edition. Ohio Valley Co., Cincinnati 1898 (English, html ).
Individual evidence
- ↑ a b M. Grieve: Calabar Bean. In: botanical.com. Retrieved August 18, 2011 .
- ↑ Lloyd 1897, p. 2.
- ↑ a b c d e Lutz Roth, Max Daunderer, Kurt Kormann: Toxic Plants - Plant Poisons. Occurrence, effect, therapy, allergic and phototoxic reactions. With a special section about poisonous animals. 6th, revised edition, special edition. Nikol, Hamburg 2012, ISBN 978-3-86820-009-6 .
- ↑ John Uri Lloyd: Physostigma venenosum (Calabar) . In: The Western Druggist . Chicago June 1897 (English, pdf ).
- ↑ Calabar Bean . In: Encyclopædia Britannica . 11th edition. London 1911 (English, wikisource ).
- ↑ Grete Ronge: Hesse, Oswald. In: New German Biography (NDB). Volume 9, Duncker & Humblot, Berlin 1972, ISBN 3-428-00190-7 , p. 20 f. ( Digitized version ).
- ^ Gerhard Madaus : Calabar. Physostigma venenosum, calabar bean. Leguminosae . In: Textbook of Biological Remedies . 1938 ( html ).
- ↑ Alex Proudfoot: The early toxicology of physostigmine: a tale of beans, great men and egos . In: Toxicological Reviews . tape 25 , no. 2 , 2006, p. 99-138 (English, abstract ).
- ^ Rosalind IJ Hackett: Religion in Calabar: the religious life and history of a Nigerian town . Walter de Gruyter & Co, 1989, ISBN 3-11-011481-X , p. 38 ff . (English, online in the Google book search).
- ↑ AHM Kirk-Greene: On Swearing. An Account of Some Judicial Oaths in Northern Nigeria . In: Africa: Journal of the International African Institute . tape 25 , no. 1 , January 1955, p. 43-53 , JSTOR : 1156895 (English).
