The star fruit contains, up to now, an unknown neurotoxin, which is removed via the kidneys of healthy people. With people suffering from kidney disease the neurotoxin accumulates and could end up in the brain. A team from the university of Sao Paulo (Brazil) has been successful in identifying and isolating this neurotoxin.
The scientists achieved this by feeding the star fruit to animals with artificial kidney damage (in order to copy the digestion of patients with kidney disease) and by injecting extracts into the brains of healthy rats. In this way attacks were stimulated, which are typical of star fruit poisoning. The extracts were fractioned and the single fractions were tested. Active fractions were then chromatgraphically analised and tested again - until the discovery of one single substance responsible for causing the attacks, was found. The scientists gave this the name of caramboxin.