Biosynthesis of antidesmone in cell cultures of Antidesma membranaceum (Euphorbiaceae):: An unprecedented class of glycine-derived alkaloids

Antidesmone (3), known from several species of Antidesma and Hyeronima (Euphorbiaceae), is a quinoline alkaloid with an unusual substitution pattern. It carries a linear aliphatic side chain that indicates an at least partially acetogenic origin of the carbon skeleton. Feeding experiments with C-13 and N-15 labeled precursors administered to cell cultures of Antidesma membranaceum yielded antidesmone, which was investigated by NMR spectroscopy. Accordingly, antidesmone is built up from a linear C-16-polyketide chain and a C-2 unit derived directly from glycine. It is thus the first representative of a biosynthetically novel class of alkaloids.