A novel acylated flavonol glycoside isolated from Brunfelsia grandiflora ssp. grandiflora. Structure elucidation by gradient accelerated NMR spectroscopy at 14T

Kaempferol-3-O-[6Glc-O-feruloyl]-β-D-glucopyranosyl-(1→2)-O-[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside (1) was isolated from the aerial parts of Brunfelsia grandiflora ssp. grandiflora. The structure of this novel flavonol glycoside was established by fast atom bombardment-mass spectrometry and by means of NMR spectroscopy at 14T, using two-dimensional NMR experiments with pulsed-field gradients for coherence selection. The presence of the constituent aglycones and sugar units of 1 was confirmed independently by acid hydrolysis.