A Fragmentation Study of Kaempferide 3,7-Di-O-glycosides by Electrospray Ionization Tandem Mass Spectrometry

A serious of new methoxylated flavonol including kaempferide mono-O-glycosides and kaempferide 3,7-di-O-glycosides from Actinidia kolomikta were studied by using electrospray ionization tandem mass spectrometry. The results indicated kaempferide mono-O and di-O have substantial difference in their fragmentation behaviors. Kaempferide mono-O-glycosides yielded abundant aglycone ion ([Y-0](-)) by loss of glycan residues, however, 3,7-di-O-glycosides mostly generated [Y-0(3)](-) and [Y-0(7)](-) ions through removal of glycan residues substituted in C-7 and C-7 respectively, but little aglycone ion from loss of all substituted glycans. Furthermore, the glycosylation site could be easily determined because the [Y-0(3)](-) and [Y-0(7)](-) ions shown different fragmentation pathways.