Persin

Persin is a fungicidal toxin present in the avocado, isolated only recently. It is generally harmless to humans, but when consumed by domestic animals in large quantities it is dangerous. It has been suggested as a treatment for breast cancer.

The chemistry of persin is not yet understood, but it is similar to a fatty acid, carried in an oil, and it leaches into the body of the fruit from the pits. Negative effects in humans seem to be primarily in allergic individuals.

Pathology
Feeding avocados or guacamole to any non-human animal should be avoided completely. The symptoms include gastrointestinal irritation, vomiting, diarrhea, respiratory distress, congestion, fluid accumulation around the tissues of the heart and even death. Birds seem to be particularly sensitive to this toxic compound.

Pits may lodge in the intestinal tract of cats and dogs and require surgery for removal.


 * In birds, the symptoms are: increased heart rate, myocardial tissue damage, labored breathing, disordered plumage, unrest, weakness, and apathy. High doses cause acute respiratory syndrome (asphyxia), with death approximately 12 to 24 hours after consumption.
 * Lactating rabbits and mice: non-infectious mastitis and agalactia after consumption of leaves or bark.
 * Rabbits: cardial arrhythmia, submandibular edema and death after consumption of leaves.
 * Cows and goats: mastitis after consumption of leaves or bark.
 * Horses: mastitis after consumption of leaves or bark.
 * Hares, pigs, rats, sheep, ostriches, chickens, turkeys and fish: symptoms of intoxication similar those described above. The lethal dose is not known; the effect is different depending upon the animal species.

Medical uses
Persin has recently been discovered to kill breast cancer cells. It has also been shown to enhance the effect of the breast cancer fighting drug Tamoxifen. This could potentially reduce the necessary dosage of current cancer drugs. Persin is however highly insoluble, and more research will be needed to put it into a soluble tablet form. The result was announced by the Garvan Institute at the Australian Society for Medical Research meeting held at the Powerhouse Museum, Ultimo, on 4 June 2007.