title: Biosynthesis of panaxynol and panaxydol in Panax ginseng.
abstract: The natural formation of the bioactive C17-polyacetylenes (-)-(R)-panaxynol and panaxydol was analyzed by 13C-labeling experiments. For this purpose, plants of Panax ginseng were supplied with 13CO2 under field conditions or, alternatively, sterile root cultures of P. ginseng were supplemented with [U-13C6]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 13C-labeled isotopologues and one single labeled isotopologue were observed in the C17-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 13C-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 13CO2 experiments under field conditions are useful to elucidate the biosynthetic pathways of metabolites, including those from roots.
authors.affiliation: Lehrstuhl für Biochemie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
authors.forename: Nihat
authors.initials: N
authors.lastname: Knispel
authors.forename: Elena
authors.initials: E
authors.lastname: Ostrozhenkova
authors.forename: Nicholas
authors.initials: N
authors.lastname: Schramek
authors.forename: Claudia
authors.initials: C
authors.lastname: Huber
authors.forename: Luis M
authors.initials: LM
authors.lastname: Peña-Rodríguez
authors.forename: Mercedes
authors.initials: M
authors.lastname: Bonfill
authors.forename: Javier
authors.initials: J
authors.lastname: Palazón
authors.forename: Gesine
authors.initials: G
authors.lastname: Wischmann
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Cusidó
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D053280:Diynes / Q000737:chemistry* / Q000378:metabolism; D005233:Fatty Alcohols / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D005894:Panax / Q000737:chemistry* / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism; D053279:Polyynes / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D053280:Diynes; D005233:Fatty Alcohols; C018541:falcarinol; D053279:Polyynes; C055778:panaxydol