Biosynthesis of the morphinandienone alkaloid, sebiferine

Abstract

The incorporation of (±)-nor-reticuline, (±)-reticuline, (±)-nor-orientaline, and (±)-laudanosine into sebiferine (O-methylflavinantine) in Cocculus laurifolius DC has been studied and the specific utilization of reticuline demonstrated. A double-labelling experiment involving the 4′-O-methyl group of (±)-nor-reticuline showed that the methoxy-function is retained in the bioconversion of the precursor into sebiferine and there was considerable loss of tritium at C-1. Parallel experiments with (+)- and (–)-reticulines showed that the stereospecificity is not maintained in the biosynthesis of sebiferine from 1-benzylisoquinoline precursors. Feeding experiments also demonstrated that the plants can also efficiently convert flavinantine into sebiferine.