Steroidal Alkaloids

STEROIDAL ALKALOIDS

They are formed by the addition of nitrogen on the similar point in the steroidal molecule, for example kurchi and veratrum. The active chemical principles of such drugs contain mainly steroidal (cyclopentenophenanthrene) entity, along with basic nitrogen. They belong to C₂₁ or C₂₇ group of steroids. Either they are used as medicines or as a pre-cursor for synthesis of various other steroids. Steroidal alkaloids contain a tetracyclic (4-ring) triterpene compound called the steroid nucleus or steroidal backbone. Because some steroidal alkaloids contain a sugar molecule, they are also referred to as alkaloidal glycosides (sugar + steroidal alkaloid). Species of nightshades (Solanum) in the tomato family (Solanaceae) contain a complex of toxic alkaloidal glycosides (glycoalkaloid). Solanine is an example of a gly-coalkaloid. Some of the important drugs under this class are Solanum species. Glycoalkaloids, principally solanine and chaconine, are present at variable concentrations in the vegetative organs of Solanum species. Glycoalkaloids are synthesized in the leaves and then translocated to the different plant organs. Although a number of factors, both abiotic—such as light, soil type and moisture, fertilization or pesticides and biotic—such as plant age, type of organ (berries, leaves, stems, sprouts and tubers) considered, tuber size, or tuber integrity (fracture damages, crushing, splits)—influence glycoalkaloid concentration; the synthesis of these molecules is also largely determined by the genetic constitution of the plant.

One of the most interesting and poisonous steroidal alkaloids is produced by Central and South American poison dart frogs of the genera Dendrobates and Phyllobates.