Solanine, alkaloid

Many human populations have only encountered some mixtures of NPs relatively recently— the first Europeans to encounter chilli peppers, many beans, pineapples, bananas, tobacco and so forth did so only a few hundred years ago. The solanine alkaloids (and other NPs) in potato or tomato were unknown to Asians, Africans and Europeans until very recently, yet these populations seemed untroubled by these novel chemicals. Tomato fruits were initially considered to be poisonous when introduced to Europe and it was only in the nineteenth century that they became widely adopted as a food plant. 

We are now aware of just how complex is the mixture of chemicals present in food. For example, for the common potato (Solanum tuberosum), besides many substances of known nutritional value, about 120 additional substances have been detected, including solanine alkaloids, oxalic acid, arsenic, etc. An additional 228 chemicals have been identified in potatoes roasted in their skins. Naturally occurring chemicals in food have been associated not only with acute toxicity, but also with cancer and other chronic diseases (11). 

Among the well-known Solanum species that have been chemically examined are S. nigrum, S. tuberosum (potato) and S. lycopersicum (tomato). From these and other species an alkaloidal glucoside, which was first prepared by Desfosses, has been obtained. This substance has been named solan ine, but it is not certain that all the plants recorded as containing solanine contain the same solanine or that the alkaloid has been obtained in a pure state in each case. 

Firbas stated that at least two of these alkaloidal glucosides occur in young potato shoots, solanine and solaneine, and that these may be accompanied by solanidine, a basic decomposition product of solanine. Solaneine was later shown to be a mixture of solanine and solanidine. 

The name solanine should be sufficient to indicate that the substance referred to is the glucosidal alkaloid first isolated from potatoes. The use of such forms as T-solanine, solanine-t and solanine tuberosum is confusing, as is also the proposed substitution of solatubine for solanine. 

The fruit of a number of solanaceous plants, including tomato Lycopersicon esculentum), potato Solanum tuberosum) and eggplant Solarium melongena esculentum), have cholinesterase-inhibiting effects (Krasowski et al. 1997). They contain solanaceous glycoalkaloids o-solanine and o-chaconine, which are triglycosides of solanidine, a steroidal alkaloid derived from cholesterol. They are the only plant chemicals known to inhibit both acetlycholinesterase and butyrylcholinesterase, both in vitro and in vivo. 

The structural features of the solanum alkaloids are based on two primary skeletal configurations solanidane, with or without glycoside functionalities, as featured by the toxic and teratogenic steroidal alkaloids a-chaconine and a-solanine with the indolizidine type E-F ring (Figure 2.7a) and the spirosolane... 

Lift and leave exposed to dry for a few hours. Store in thick paper sacks, tied or folded loosely at the neck. Potatoes must be stored in the dark to prevent them from turning green and developing high levels of solanine, a toxic alkaloid. Frost protection is essential. Ideal storage temperature is 41-50°F (5-10°C). 

Alkaloids are active bioagents in animal tissues. There is clear scientific evidence of this. Crawford and Kocan" " have tested the toxicity of steroidal alkaloids from the potato Solanum tuberosum), such as a-chaconine, a-solanine, solanidine and solasodine, and Veratrum alkaloid, jervine on fish. The results of Crawford and Kocan s research proved that rainbow trout exhibited a toxic response to chaconine, solasidine and solanine, while medaka only did so to chaconine and solanine. Embryo mortality was observed as an effect of toxicity in both species. Many other alkaloids are known to disturb or cause disorder in animal reproductive systems. For example, gossypol from cotton-seed oil is known as a clear reducer of spermatogenesis and premature abortion of the embryo. 

Steroidal alkaloids These alkaloids have a core steroidal skeleton as part of the molecule, e.g. solanine. There are a number of structural varieties that exist in steroidal alkaloids. Following discussion is just on a few selected steroidal alkaloids. 

Solanine is a poisonous steroidal alkaloid, also known as glycoafkaloid, found in the nightshades family (Solanaceae). It is extremely toxic even in small quantities. Solanine has both fungicidal and pesticidal properties, and it is one of the plant s natural defences. 

Solanum indicum L. Niu Zi Qie (Indian nightshade) (root, leaf, fruit) Diosgenin, solanidine, solanine, solasodine, alkaloids, carbohydrases, maltase, saccharase, melibiase.50 Antidote for poison, for urinary disease. 

The Solanaceae family includes not only deadly nightshade (Atropa belladonna—hence atropine) plants but also potatoes and tomatoes. Parts of these plants also contain toxic alkaloids for example, you should not eat green potatoes because they contain the toxic alkaloid solanine. 

Returning to the question in the title of this section, capsaicin does not fall into any of the three classic types of nitrogen-bearing plant natural products, being neither a true alkaloid, a protoalkaloid, or a pseudoalkaloid. Capsaicin is oflimited distribution in Nature and shows pharmacological activity, but is non-basic, structurally unsophisticated, and not directly derived from an amino acidic precursor. On the other hand, the lack of attributes such as basicity, complexity, and an amino acidic pedigree can also be found in compounds commonly perceived as alkaloids. Thus, colchicine is neutral, ephedrine is structurally unsophisticated, and the nitrogen atom of the potato alkaloid solanine is not derived from an amino acid, but rather incorporated into as non-amino acidic framework by a transamination reaction. For the sake of clarity and consistency, it seems therefore convenient to adopt the modern definition of alkaloids, and consider capsaicin, as well as alkylamides such as piperine (18) and pellitorine (19), as such. 

These complex systems are also targets of many natural products (Table IV). Disturbance of membrane stability is achieved by 9-methoxyelliptic-ine, ellipticine, berbamine, cepharanthine, tetrandrine, steroidal alkaloids, irehdiamine, and malouetine. Steroidal alkaloids, such as solanine and tomatine, which are present in many members of the Solanaceae, can complex with cholesterol and other lipids of biomembranes cells are thus rendered leaky. 

An alkaloid present in various species of Solanum. (Solanaceae). It is the aglycone of solanine. 

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