摘要 : The natural formation of the bioactive C_(17)-polyacetylenes (?)-(R)-panaxynol and panaxydol was analyzed by ~(13)C-labeling experiments. For this purpose, plants of Panax ginseng were supplied with ~(13)CO2 under field conditions... 展开 The natural formation of the bioactive C_(17)-polyacetylenes (?)-(R)-panaxynol and panaxydol was analyzed by ~(13)C-labeling experiments. For this purpose, plants of Panax ginseng were supplied with ~(13)CO2 under field conditions or, alternatively, sterile root cultures of P. ginseng were supplemented with [U-~(13)C6]glucose. The polyynes were isolated from the labeled roots or hairy root cultures, respectively, and analyzed by quantitative NMR spectroscopy. The same mixtures of eight doubly ~(13)C-labeled isotopologues and one single labeled isotopologue were observed in the C_(17)-polyacetylenes obtained from the two experiments. The polyketide-type labeling pattern is in line with the biosynthetic origin of the compounds via decarboxylation of fatty acids, probably of crepenynic acid. The ~(13)C-study now provides experimental evidence for the biosynthesis of panaxynol and related polyacetylenes in P. ginseng under in planta conditions as well as in root cultures. The data also show that ~(13)CO2 experiments under field conditions are useful to elucidate the biosynthetic pathways of metabolites, including those from roots. 收起