Solanine, more precisely α-Solanine, is a slightly toxic chemical compound that is mainly found in nightshade plants such as potatoes and tomatoes. Chemically, solanine is the saponine of the steroid alkaloid solanidine with the trisaccharide solatriose, which consists of glucose, galactose and rhamnose. Solanine was first isolated from the berries of the black nightshade (Solanum nigrum) in 1820 by the French pharmacist Desfosses, after whom it was named. It is also incorrectly called “Tomatine”.

Solanine poisoning
Solanine poisoning used to be very common, especially in the form of a “heavy stomach” and nausea; Deaths have also been described. It has practically disappeared today due to the low concentrations in modern cultivated vegetables. The first symptoms of poisoning of the alkaloid, such as drowsiness, hypersensitivity to touch (hyperesthesia) and difficult breathing (dyspnoea), occur in adults after ingestion of approx. 200 mg; nausea and vomiting occur with continued solanine intake; these symptoms are also described as solanism.[4] Other symptoms include burning and scratchy throat, stomach problems, intestinal inflammation, kidney inflammation with bloody urine, body aches, fever, kidney irritation, diarrhea and in severe cases even the dissolution of red blood cells, cardiac arrhythmias, disorders of circulatory and respiratory activity and damage to the central nervous system ( cramps, paralysis). A dose of 400 mg is considered fatal.

Solanine does not break down during cooking, but rather passes into the water used for cooking because it is water-soluble at high temperatures. Therefore, the cooking water should not be used afterwards. Since solanine is heat-stable and fat-insoluble, it is not destroyed when deep-fried or roasted. The solanine content of potatoes can be reduced by cutting off green areas and sprouts. Since the green color comes from chlorophyll and its formation only occurs after the biosynthesis of solanine, even uncolored potatoes can have an increased solanine concentration.