Metabolism of N-alkyldiamines and N-alkylnortropinones by transformed root cultures of Nicotiana and Brugmansia

Abstract

A range of analogues of N-methylputrescine and tropinone were fed to transformed root cultures of Nicotiana rustica and/or a Brugmansia candida× aurea hybrid. These cultures were made by the transformation of the relevant plant species with Agrobacterium rhizogenes. A number of the metabolites, notably those showing a relatively modest alteration in the N-alkyl substituent, were metabolized in vivo to form homologues of the normal alkaloids biosynthesized by these roots. These products were identified by GC/MS and comparison with some synthetic reference materials. Analogues with major alterations in the size of the N-alkyl substituent were not metabolized at all. In the N. rustica cultures, the analogues fed at 1 mM significantly affected the profile of normal alkaloids, with up to a 4-fold diminution in nicotine being found in the presence of N- n-propylputrescine. The ratio between alkaloids of the pyrrolidine series and the piperideine series was also affected. In contrast, the presence of the analogues in the B. candida× aurea hybrid culture at 1 mM did not inhibit or substantially interfere with the accumulation of the normal spectrum of alkaloids. The potential for using these cultures to make complex novel products from simple precursors is discussed.