It is very toxic even in small quantities. The poisoning is primarily manifested by gastrointestinal and neurological disorders. Symptoms include nausea, diarrhea, vomiting, stomach cramps, burning of the throat, heart arrhythmia, headache, and dizziness.
Most people can easily cope with the solanine in the average portion of potato and show no symptoms of poisoning because the body can break it down and rapidly and excrete the products in the urine.
Mechanism of action
Solanum glycoalkaloids have been shown to inhibit cholinesterase, disrupt cell membranes, and cause birth defects. One study suggests that the toxic mechanism of solanine is caused by the chemical's interaction with mitochondrial membranes.
Solanine is a toxic glycoalkaloid known to accumulate under certain conditions in potato plant, sprouts and tuber in levels which, if ingested, may cause poisoning in humans and farm animals.
Solanine is a type of alkaloid which is toxic in large amounts and can promote inflammation—but it's almost entirely found in the leaves and stems of these vegetables, not the parts we eat.
Sweet potatoes and yams do not contain solanine. Most yams that you see on grocers shelves are actually sweet potatoes. They have a moderately moist texture and orange flesh. The native sweet potato flesh is dry and pale yellow to whitish.
Solanine is a bitter-tasting steroidal alkaloid saponin that has been isolated from all nightshades, including tomatoes, capsicum, tobacco, and eggplant. However, the most widely ingested solanine is from the consumption of potatoes. Potato leaves, stems, and shoots are naturally high in this saponin.
The solanine, or tomatine, level dramatically decreases in fully ripe tomatoes, to levels less than 5 mg per 1 kg of fruit weight. These low levels pose no health problems to humans, but even in the ripened form the solanine remaining in a tomato is harmful to cats.
It is reported that they are poorly absorbed by the human body and rapidly excreted. Solanines are not destroyed by cooking, but both boiling and frying do reduce the amount of these compounds.
Solanine has been shown anticarcinogenic potential against various cancer cell lines, but the underlying mechanism involved in inhibition of tumor growth by solanine remains to be further elucidated.
A person with a nightshade allergy may develop breathing problems, a rash, or eczema shortly after eating certain vegetables. A nightshade intolerance or sensitivity means the foods are not digested properly, which can cause a range of symptoms, including digestive issues.
If your potatoes smell bitter, don't eat them, experts say.
Thankfully there are two common signs that a potato has developed dangerous levels of solanine: they can give off a bitter smell, and their skin may turn a shade of green.
New and fingerling potatoes offer the advantage that they contain fewer toxic chemicals. Such potatoes offer an excellent source of nutrition. Peeled, long-stored potatoes have less nutritional value, especially when fried, although they still have potassium and vitamin C.
Some people believe that you can eat green, unripe tomatoes if they are cooked, but that is not true. Tomatine and solanine are very resistant to heat and do not break down during preparation, whether that be boiling, baking or frying.
chlorophyll, which shows up as green areas on potatoes and causes eyes to sprout, giving visual clues to the presence of unusually high levels of solanine in potatoes. Green areas and eyes should be cut away before cooking. Garlic, on the other hand, does not contain solanine.
-Chaconine and -solanine occur naturally in potatoes (Solanum tuberosum) and other members of the Solanaceae family. Solanine is also present in apples, bell peppers, cherries, sugar beets, and tomatoes.
Myth: Nightshade vegetables contain a toxic alkaloid
Contrary to the rumours, however, eggplant, peppers and tomatoes — even the green ones — do not produce solanine and are perfectly safe to eat, he says.
Solanine is a glycoalkaloid to be found in potatoes. Glycoalkaloids are secondary plant in- gredients occurring in plants of the nightshade family as a defence mechanism against pests and germs. Potato tubers mainly contain the glycoalkaloids α-solanine and α-chaconine, mostly in the peel of the tubers.
Solanine is also found in eggplant, apples, bell peppers, cherries, sugar beets and tomatoes.
Nightshade vegetables include potatoes, tomatoes, and eggplant. These vegetables are rich in nutrients and often recommended as staples of a healthy diet. Nightshades contain the alkaloid solanine, which is toxic in high concentrations. Potatoes that have turned green are most likely to induce solanine toxicity.
CONSTITUTION: Solanin is removed from potatoes by dipping the potatoes in vinegar of 30-60 deg. C, containing 0.3-1.0 vol% of acetic acid, for 2-5 minutes.
Zucchini, cucumbers, and mushrooms are not nightshades, even though many people think they are.
Onions are not nightshades either.