Chapter II Alkaloids in the Plant

Abstract

Publisher Summary The formation of the simpler nitrogen bases is universal, and at the present time, it is receiving ever-increasing attention as their importance in vitamins, hormones, and coenzymes becomes more apparent. Although the impetus has come primarily from their systemic action, a further study of the alkaloids while still in the plant is likely to make valuable contributions to the general study of the plant's nitrogen metabolism. Taking into account the extremely varied molecular structures that are included under the general heading of alkaloids, it is improbable that the behavior of all will be alike in the various species that produce them. A detailed treatment would necessitate breaking up the collection into a number of separate groups on physiological as well as chemical grounds. At present, adequate data for such a systematic treatment do not exist, and only a few groups have received serious attention. These must be taken as representing all we know of alkaloids in general. Among these limited groups, similarities and differences of physiological behavior are both evident. Among the similarities, following enable to consider alkaloid metabolism a reasonable unity: All alkaloids are associations of nitrogen with carbon and hydrogen, which places them in a rather definite category in metabolism. Heterocyclic and aromatic rings abound in their structures, indicating some degree of similarity in their formation, even though ring closure may take place at different stages and in different ways. Methylation must also be of frequent occurrence in the metabolism of different alkaloid groups, since many methylated and non-methylated forms exist side by side.