Indole alkaloids strictosidine group

Strictosidine synthase has a wide distribution among plants, although it is functionally expressed in a small group of taxa producing monoterpene indole alkaloids (see arrow in Fig. 7.17b). Related genes occur in animals and... 

L-Tryptophan was shown to be incorporated with high efficiency into 5a-carboxystrictosidine (33a) in Rhazya orientalis, from where it was originally isolated. It joins the small group of indole alkaloids which retain the carboxyl of precursor tryptophan. The di-acid (33c) and the acid (33b), corresponding to strictosidine, were also isolated in this study. 

The terpenoid indole alkaloids are a group of plant bases derived by multiple variation on the strictosidine [(79) p. 20] skeleton. Arguably the most important work in the past five years has been done on these alkaloids with enzyme preparations from plant tissue cultures, and the research is of great potential significance for other studies in alkaloid biosynthesis. The results have allowed close definition of the early stages of biosynthesis (this Report, p. 19). Use of crude enzyme preparations in this way has been extended to the study of benzylisoquinoline biosynthesis, with enzyme-catalysed formation of norlaudanosoline-1-carboxylic acid [(57) p. 16] this compound had earlier been identified as the first of the benzylisoquinolines (this Report, p. 15). It seems that amino-acids of this general formula (6) are key intermediates in the biosynthesis of all isoquinoline alkaloids. Lophocereine (7) is exceptional in that two routes (from leucine and mevalonate) may lead to it, only one of which potentially involves an acid like (6). ... 

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