Identification of aromatic cytokinins in suspension cultured photoautotrophic cells of Chenopodium rubrum by capillary liquid chromatography/frit – fast atom bombardment mass spectrometry

Two previously unrecorded endogenous cytokinin metabolites,6-[2-(β-D-glucopyranosyloxy)benzylamino]purine and6-[2-(β-D-glucopyranosyloxy)benzylamino]-2-methylthiopurine, wereidentified, together with 6-benzylamino-9-β-D-glucopyranosylpurine(BAP9G),from Chenopodium rubrum cells, grown autotrophically insuspension culture. The new metabolites belong to the aromatic class ofcytokinins, in which an aromatic side chain is attached at theN6-position of the adenine species. The identification was performedby capillary-liquid chromatography/frit-fast atom bombardment - massspectrometry (LC/FAB MS) after pre-column derivatisation and the structuralelucidation was confirmed by organic synthesis. Cytokinin activity of thecompounds was tested in an Amaranthus bioassay. Theendogenous synthesis of the identified compounds was verified byin vivo deuterium labelling of the analysed cytokininspecies, thereby for the first time providing absolute evidence for theendogenous origin of these compounds.