The unripened or inedible portions of the fruit contain the
toxin hypoglycin A and
hypoglycin B, known as "soapberry toxins".
[4][15] Hypoglycin A is found in both the seeds and the arils, while hypoglycin B is found only in the seeds.
[6] Minimal quantities of the toxin are found in the ripe arils.
[16] In the unripe fruit, depending on the season and exposure to the sun, the concentrations may be up to 10 - 100 times greater.
[16]
These two molecules are converted in the body to
methylenecyclopropylacetic acid (MCPA), and are toxic with potential
lethality.
[4] MCPA and hypoglycin A inhibit several
enzymes involved in the breakdown of
acyl CoA compounds, often binding irreversibly to
coenzyme A,
carnitine and
carnitine acyltransferases I and II,
[17] reducing their bioavailability and consequently inhibiting
beta oxidation of
fatty acids. Glucose stores are consequently depleted leading to
hypoglycemia[18] and a condition called
Jamaican vomiting sickness.
[1][15] These effects occur only when the unripe fruit is consumed.
[1][15][19]
Though ackee is used widely in traditional dishes, research on its potential hypoglycin toxicity has been sparse and preliminary, requiring evaluation in well-designed
clinical research to better understand its
pharmacology, food uses, and methods for detoxification.
[20]
