Solanine distribution

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. 

The distribution of alkaloids among the various organs of V. lobelianum has been investigated. The isolation of y-solanine from V. lobelianum has been reported. ... 

The two most widely distributed glycoalkaloids, solanine and solason-ine, as well as the less-known solauricine and the alkaloid from Solanum panduraeforme Drege contain as sugar component a trisaccharide, L-rhamnosido-D-galactosido-D-glucose (I), for which the name solanose has been proposed (11, 12, 13, 14, 38, 60, 62). 

The distribution of glycoalkaloids differs in the various parts of plants. a-Solanine and a-chaconine occur in roughly equal amounts. The largest amount of solanine in potato is present in the flowers (5000mg/kg) and germ (1950-4360mg/kg). The highest concentrations in tubers are in the surface layers. Towards the... 

---