solanine

Solanine is a glycoalkaloid poison produced by plants in the nightshade family (Solanaceae). The term commonly refers to two closely related compounds found in potatoes, alpha-solanine and alpha-chaconine, which can occur together in the tubers. Related alkaloids, such as tomatine, are present in tomatoes and other nightshade species at lower levels.

Chemically, solanine is a steroidal alkaloid glycoside. The aglycone, solanidine, is bonded to sugar molecules, forming multiple glycoside forms. The potato plant and some other Solanum species synthesize these compounds as part of a natural defense against pests.

Occurrence in foods varies. Potatoes typically contain higher levels, especially in the skin, sprouts, or green portions exposed to light. Tomatoes contain tomatine rather than large amounts of solanine, and eggplants have only trace amounts of related alkaloids. Normal ripe potatoes and well-cooked vegetables generally present little risk, but greened or sprouted potatoes can accumulate higher concentrations.

Toxicity and effects. Ingestion of large amounts can produce gastrointestinal symptoms such as nausea, vomiting, and diarrhea, and may cause dizziness, headache, and neurological symptoms in severe cases. Solanine may disrupt cell membranes and, in some circumstances, inhibit acetylcholinesterase, affecting nervous system signaling. Toxic doses vary with body weight and individual sensitivity; young children are more susceptible.

Safety and handling. Cooking reduces but does not eliminate solanine; it is advised to avoid consuming green, sprouted, or badly damaged potatoes and to store potatoes in dark, cool, ventilated conditions. Removing the skin and sprouts and discarding green areas can lower exposure. There is no universal culinary limit, but prudent preparation practices help minimize risk.