Caramboxin (CBX) is a toxin found in star fruit (Averrhoa carambola). Individuals with some types of kidney disease are susceptible to adverse neurological effects including intoxication, seizures and even death after eating star fruit. Caramboxin has been identified as the neurotoxin responsible for these effects. Caramboxin is a non-proteinogenic amino acid that stimulates the glutamate receptors in neurons. Its chemical structure is similar to the amino acid phenylalanine. Caramboxin is an agonist of both NMDA and AMPA glutamatergic ionotropic receptors with potent excitatory, convulsant, and neurodegenerative properties.
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3D model (JSmol)
|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).
Due to a possible interaction between caraboxin and oxalic acid in starfruit leading to both neurotoxic and nephrotoxic effects, eating starfruit or drinking its juice on an empty stomach is not recommended, even for individuals with normal kidney function.
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