Methylene cyclopropyl acetic acid

Methylene cyclopropyl acetic acid

Names
IUPAC name 2-(2-methylidenecyclopropyl)acetic acid
Other names MCPA; Methylenecyclopropaneacetic acid
Identifiers
CAS Number	1073-00-3
ChEMBL	ChEMBL314481
ChemSpider	8389873
Jmol interactive 3D	Image
PubChem	10214381
InChI InChI=1S/C6H8O2/c1-4-2-5(4)3-6(7)8/h5H,1-3H2,(H,7,8) Key: QJBXAEKEXKLLLZ-UHFFFAOYSA-N
SMILES OC(=O)CC1CC1=C
Properties
Chemical formula	C6H8O2
Molar mass	112.13 g·mol^−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Methylene cyclopropyl acetic acid (MCPA) is found in lychee seeds and also a toxic metabolite in mammalian digestion after ingestion of hypoglycin.

Overview

Methylene cyclopropyl acetic acid (MCPA) is a compound found in lychee seeds.^[1] It is also a metabolite in mammalian digestion after ingestion of hypoglycin, a rare and potentially toxic amino acid, chemically related to the common amino acid lysine. (Hypoglycin is found in the unripe ackee fruit in Africa.)

Dihydrosterculic acid is the major carbocyclic fatty acid in the seed oils of Litchi chinensis. It is a cyclopropene fatty acid; these have been found in many plants of the order Malvales (Sterculiaceae, Malvaceae, Bombaceae and Tiliaceae), in up to 60% of seed oil content, depending on the species but also in leaves, roots and shoots.^[2] They are accompanied by small amounts of their cyclopropanoid analogues, i.e. cyclopropyl acetic acid.

Symptoms and signs of poisoning

The symptoms of poisoning are intolerance to prolonged fasting, vomiting, altered mental status with lethargy, progressing to unconsciousness, coma and death.^[3]

Mechanism of toxicity per animal studies

MCPA is a potent inhibitor of acyl CoA dehydrogenase, thus preventing the metabolism of fatty acids. The intolerance to prolonged fasting is due to inability to switch from glucose to fatty acid oxidation, impaired ketogenesis. There is increased urinary excretion of dicarboxylic acids, due to omega oxidation that occurs in the endoplasmic reticulum.^[4]

References

1. Gray DO, Fowden L. alpha-(methylenecyclopropyl)glycine from litchi seeds. Biochem J 1962;82:385–9.PMC 1243468
2. "Natural alicyclic fatty acids, section:Cyclopropane and Cyclopropene Fatty Acids from Plants". The AOCS Lipid Library. American Oil Chemists' Society. n.d. Retrieved 2 February 2015.
3. Melde K, Jackson S, Bartlett K, Sherratt HS, Ghisla S. Metabolic consequences of methylenecyclopropylglycine poisoning in rats. Biochem J 1991;274:395–400. PMID 2006907 PMC1150150
4. Melde K, Buettner H, Boschert W, Wolf HP, Ghisla S. Mechanism of hypoglycaemic action of methylenecyclopropylglycine. Biochem J 1989;259:921–4.PMC1138607