Other Roles of Alkaloids

A favorite topic for discussion is the metabolic status of alkaloids. The most common notion is that alkaloids are waste products which play an 

Hydroxylation and epoxidation reactions, although they can represent catabolic modifications of alkaloids, have not been included here for two reasons. One is that these processes are traditionally included in the biosynthetic pathways of alkaloids that contain the corresponding groups the other is that only in some alkaloids, such as scopolamine and 6-hydroxyhyoscyamine, are such groups probably introduced by modification of a preformed alkaloid skeleton. In other alkaloids, the hydroxyl groups are already present in the precursors, e.g., phenolic groups in materials from which the isoquinoline esters (Jindra et al., 1964) have not been included. Since this review is mainly about the catabolism of the heterocyclic rings, these have been left out. 

Dawson and Osdene s (1972) report gives a speculative view of tobacco alkaloid metabolism and deals primarily with alkaloid biosynthesis. Sadykov, Aslanov, and Kushmuradov (1975) provide a limited view of alkaloid catabolism but cover the biosynthesis of the quinolizidines adequately. 

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