Isolation and Characterization of an Unknown Flavonoid in Dry Extracts from<i>Passiflora incarnata</i>

Abstract

Abstract HPLC analyses of dry extracts obtained from Passiflora incarnata revealed the presence of ten known flavonoids whose structures were characterised by ionspray ioni-zation tandem mass spectrometry; in addition, three unidentified peaks, F1, F2, and F3 appeared in the flavonoid region of the chromatogram. Two components were detected in F3 by on-line HPLC-ISI-MS analysis, named F3a and F3b. F2 was demonstrated to be a structural isomer of schaftoside (1), and F3a of isoschaftoside (2), with apigenin as the common aglycone and molecular weight 564. Mass spectra and 2D-NMR experiments allowed us to assign the structure of 6-β-D-glucopyranosyl-8-β-D-ribopyranosyl apigenin to the new di-C-glycosylflavonoid F2.