LC-MSMS profiling of flavonoid conjugates in wild Mexican lupine, Lupinus reflexus

Profiles of flavonoid conjugates present in the root and leaf tissues of the Mexican wild lupine, Lupinus reflexus, were established using two LC-MSMS systems in the positive and negative ion modes. The ion trap mass spectrometer and quadrupole time-of flight instrument provided sequential MS(n) spectra and MSMS spectra with accurate m/z values of [M + H](+) and [M - H] (-) ions, respectively. Sixty-two flavone and isoflavone glycoconjugates were found and tentatively identified. Numerous isomeric or isobaric compounds with the same molecular mass could be differentiated. Isomeric di- and mono glucosides of biochanin A, genistein, 2'-hydroxygenistein, luteone, and 2,3-didehydrokievitone were distinguished on the basis of relative abundances of product ions. The studied flavonoid glycoconjugates were acylated with dicarboxylic aliphatic acids and their methyl esters at either the aglycone or glycosidic moiety.