Biosynthesis of Erythrina alkaloids in Erythrina crista-galli.
A precursor application system was developed to allow the study of Erythrina alkaloid formation in Erythrina crista-galli. Fruit wall tissue of this species was recognized as the major site of alkaloid biosynthesis. The application of radioactively and 13C-labelled potential precursors showed that the hitherto assumed precursor (S)-norprotosinomenine was not incorporated into the Erythrina alkaloids. In contrast, (S)-coclaurine as well as (S)-norreticuline were metabolized to erythraline and erythrinine, respectively, suggesting that a coclaurine-norreticuline pathway is operative in Erythrina alkaloid formation. Feeding of [1-13C]-labelled (S)-norreticuline with subsequent NMR spectroscopy demonstrated that the resulting erythraline was exclusively labelled at position C-10. Therefore, the participation of a symmetrical intermediate of the diphenoquinone type in Erythrina alkaloid biosynthesis can be excluded.
Maier
U H
UH
Institut für Pharmazeutische Biologie, Ludwig-Maximilians-Universität München, Germany.
Rödl
W
W
Deus-Neumann
B
B
Zenk
M H
MH
D000470:Alkaloids / Q000096:biosynthesis* / Q000737:chemistry; D001345:Autoradiography; D002855:Chromatography, Thin Layer; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010946:Plants, Medicinal / Q000378:metabolism*
D000470:Alkaloids