BIOSYNTHESIS OF THE ISOPRENE UNITS OF CHAMOMILE SESQUITERPENES

Chamomile sesquiterpenes were labelled with C-13 by injection of an [1 -C-13]glucose solution into the anthodia of the plant. The sesquiterpe nes bisabololoxide A and chamazulene were isolated from the hydrodisti llate of the labelled flowers. Analysis of the labelling patterns and absolute C-13 abundances using quantitative C-13 NMR spectroscopy show ed that two of the isoprene building blocks were predominantly formed via the new triose/pyruvate pathway, whereas the third unit was of mix ed origin, being derived from both the mevalonic acid pathway and the triose/pyruvate pathway. (C) 1998 Elsevier Science Ltd. All rights res erved.