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| Names | |
|---|---|
| IUPAC name 2-Carboxy-3-hydroxy-5-methoxy-L-phenylalanine | |
| Systematic IUPAC name 2-[(2S)-2-Amino-2-carboxyethyl]-6-hydroxy-4-methoxybenzoic acid | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
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PubChem CID | |
| UNII | |
CompTox Dashboard (EPA) | |
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| Properties | |
| C11H13NO6 | |
| Molar mass | 255.226 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Caramboxin (CBX) is a toxin found in star fruit (Averrhoa carambola) [1] [2] and the related bilimbi fruit ( Averrhoa bilimbi ). [3] Individuals with some types of kidney disease are susceptible to adverse neurological effects including intoxication, seizures and even death after eating star fruit [4] and bilimbi fruit. [3] In 2013, caramboxin was identified as the neurotoxin responsible for these effects. [2]
Caramboxin is a non-proteinogenic amino acid, with a chemical structure similar to the amino acid phenylalanine, but with extra hydroxyl, carboxyl and methoxy substituents, making it also a phenol, a benzoic acid, and a phenol ether. Caramboxin stimulates the glutamate receptors in neurons, being an agonist of both NMDA and AMPA glutamatergic ionotropic receptors with potent excitatory, convulsant, and neurodegenerative properties, [2] resulting in symptoms of central nervous system disorder, including mental confusion, seizures, and status epilepticus. [5]
A possible interaction between caramboxin and oxalic acid in starfruit can lead to both neurotoxic and nephrotoxic effects. [6] Consuming large amounts of starfruit or its juice on an empty stomach is not recommended, even for individuals with normal kidney function. [6] [7] As caramboxin is water soluble, intense hemodialysis has often been used to improve the outcome for patients. [6]
An enantioselective total synthesis of caramboxin was first published in 2024. It involves a catalytic phase-transfer alkylation of a glycine imine by ethyl acetoacetate. [8]