title: Nicotine demethylation in Nicotiana cell suspension cultures: N'-formylnornicotine is not involved.
abstract: Nicotine or nornicotine enriched with stable isotopes in either the N'-methyl group or the pyrrolidine-N were fed to Nicotiana plumbaginifolia suspension cell cultures that do not form endogenous nicotine. The metabolism of these compounds was investigated by analysing the incorporation of isotope into other alkaloids using gas chromatography-mass spectroscopy (GC-MS). Nicotine metabolism primarily resulted in the accumulation of nornicotine, the N'-demethylation product. In addition, six minor metabolites appeared during the course of nicotine metabolism, four of which were identified as cotinine, myosmine, N'-formylnornicotine and N'-carboethoxynornicotine. While cotinine was formed from [(13)C,(2)H(3)-methyl]nicotine without dilution of label, N'-formylnornicotine was labelled at only about 6% of the level of nicotine and N'-carboethoxynornicotine was unlabelled. Feeding with [1'-(15)N]nornicotine resulted in incorporation without dilution of label into both N'-formylnornicotine and N'-carboethoxynornicotine. This pattern strongly indicates that, while nornicotine and cotinine are derived directly from nicotine, N'-formylnornicotine and N'-carboethoxynornicotine are metabolites of nornicotine. Thus, it is directly demonstrated that N'-formylnornicotine is not an intermediate in nicotine demethylation.
authors.affiliation: Laboratoire de Phytotechnologie, EA 3900, Université de Picardie, Amiens, France.
authors.forename: Trixie Ann
authors.initials: TA
authors.lastname: Bartholomeusz
authors.forename: Ramneek K
authors.initials: RK
authors.lastname: Bhogal
authors.forename: Roland
authors.initials: R
authors.lastname: Molinié
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Felpin
authors.forename: Monique
authors.initials: M
authors.lastname: Mathé-Allainmat
authors.forename: Anna-Carolin
authors.initials: AC
authors.lastname: Meier
authors.forename: Birgit
authors.initials: B
authors.lastname: Dräger
authors.forename: Jacques
authors.initials: J
authors.lastname: Lebreton
authors.forename: Albrecht
authors.initials: A
authors.lastname: Roscher
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Robins
authors.forename: François
authors.initials: F
authors.lastname: Mesnard
mesh_terms: D000470:Alkaloids / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D003367:Cotinine / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D008745:Methylation; D009538:Nicotine / Q000031:analogs & derivatives* / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology* / Q000378:metabolism*
chemical_list: D000470:Alkaloids; D009587:Nitrogen Isotopes; C506430:N'-formylnornicotine; D009538:Nicotine; C005311:nornicotine; C002398:myosmine; D003367:Cotinine