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Names | |
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IUPAC name
(S)-2-Amino-3-((S)-2-methylenecyclopropyl)propanoic acid
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Other names
Hypoglycin A; Hypoglycine; 2-Methylenecyclopropanylalanine
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Identifiers | |
3D model (JSmol)
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ChEMBL | |
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PubChem CID
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UNII | |
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Properties | |
C7H11NO2 | |
Molar mass | 141.170 g·mol−1 |
Melting point | 282 °C (540 °F; 555 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Hypoglycin, or most commonly hypoglycin A, is a toxic molecule, and a naturally occurring amino acid derivative found in the unripened fruit of the Ackee tree (Blighia sapida). Hypoglycin is toxic if ingested and is the causative agent of Jamaican vomiting sickness.[1] It competitively binds to enzymes used in the catabolism of lysine and is the reason why it and its metabolite methylene cyclopropyl acetic acid (MCPA) are toxic.
History
editThe Ackee tree, and thus its fruit, originated in Africa and made its way to the Caribbean sometime in the 18th century by Captain Bligh[2], though the exact date of transfer is unknown. Its primary consumption and the majority of deaths occur in Jamaica, where it is included in the national dish: Ackee with saltfish. The entirety of the unripe Ackee fruit is toxic and contains large amounts of hypoglycin. The fruit is safe to eat only when the fruit is allowed to fully open and expose the large black seeds while on the tree. The levels of the toxin decrease over time though from approximately 1000 ppm to around 0.1 ppm in the mature fruit.[3] The seeds also contain an alternate form of hypoglycin, Hypoglycin B, which can also cause Jamaican vomiting sickness. Due to the toxicity of the fruit, importation of it is banned in the United States.[2] Since 1980, 271 cases of Jamaican vomiting sickness have occurred in Jamaica alone, with occasional outbreaks happening in other parts of the world, such as Haiti where over 100 cases of illness were reported in late 2000.[3]
Symptoms and biological effects of hypoglycin poisoning
editSymptoms
editWhen the unripe fruit of the Ackee tree is ingested, the following symptoms arise:
In severe cases of poisoning, death can also occur, which on average occurs after 12 hours.[4] In addition to the above symptoms, hypoglycin intoxication can be determined by an excess of medium chain fatty acids in urine and acidosis.
Mechanism of action
editThe molecule responsible for the toxicity of hypoglycin is actually a metabolite of hypoglycin, methylenecyclopropane acetyl (MCPA). MCPA can then react with two important cofactors for fatty acid oxidation, carnitine and coenzyme A, which both has the effects of reducing the levels of these in tissue, and, in the case of coenzyme A, blocking some CoA dehydrogenase enzymes which are required for gluconeogenesis.[3] The reduction in gluconeogenesis and the reduction in fatty acid oxidation is thought to be the cause of most of the symptoms of Jamaican vomiting sickness. The blocking of fatty acid metabolism causes cells to start using glycogen for energy. Once glycogen is depleted, the body is unable to produce more, which leads to a severe case of hypoglycemia.
Treatment
editIf the poisoning is caught early enough, gastric lavage or a slurry of activated charcoal can be administered to prevent as much absorption of the toxin as possible. Glucose should be given via an IV, which has been shown to significantly quicken recovery, though is not proven to prevent death. After these measures, treatment of symptoms is the most effective way to treat the poisoning. Fluids can be administered depending on the amount of vomiting and administration of a benzodiazepine is suggested for seizures and hemodialisis in the case of renal failure.[4]
Synthesis
editIn 1958, John Carbon, William Martin, and Leo Swett were the first to synthesize hypoglycin, starting from 2-bromopentene and ethyl diazoacetate[5]
See also
editReferences
edit- ^ "Ackee Fruit Toxicity". Medscape.
- ^ a b "Plant toxins, Ackee poisoning". Institute of Tropical Medicine Antwerp.
- ^ a b c "THE ACKEE FRUIT (BLIGHIA SAPIDA) AND ITS ASSOCIATED TOXIC EFFECTS". University of British Columbia.
- ^ a b "Hypoglycin". National Institute of Health.
- ^ Carbon, J. A.;Martin, W. B.;Swett, L. R. (1958), "SYNTHESIS OF α-AMINO- METHYLENECYCLOPROPANEPROPIONIC ACID (HYPOGLYCIN A)", J. Am. Chem. Soc., 80 (4): 1002, doi:10.1021/ja01537a066
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