hypoglycin

Hypoglycin is the name given to a family of toxic amino acids, most notably hypoglycin A and hypoglycin B, that occur in certain seeds and fruits, especially the ackee tree (Blighia sapida). The toxin became known after outbreaks of Jamaican vomiting sickness linked to eating unripe ackee fruit or seeds; mature ripe arils are typically safe when properly prepared.

Hypoglycin is a pro-toxin that is metabolized to methylenecyclopropylacetyl-CoA (MCPA-CoA), which inhibits multiple acyl-CoA dehydrogenases in the mitochondrial beta-oxidation pathway. This blocks fatty acid oxidation, leading to hypoglycemia and energy deficiency, particularly in the liver and heart. Accumulation of fatty acids can cause hepatic steatosis.

Onset is typically within hours of ingestion and includes vomiting, abdominal pain, dehydration, weakness, hypoglycemia, tachycardia, seizures, and in severe cases coma. Diagnosis involves clinical history and detection of hypoglycin A/B in biological samples; treatment is supportive, focusing on correcting hypoglycemia, fluids, and avoiding fasting; there is no specific antidote. Recovery depends on prompt supportive care.

Ackee fruits should be consumed only when fully ripe and properly prepared; unripe fruit and seeds are highly toxic. Commercial processing, cooking, or canning reduces hypoglycin content, but ingestion of unripe fruit remains dangerous. Education and regulation exist in regions where ackee is eaten.