Further lipophilic flavonols in Vellozia graminifolia (Velloziaceae) by high temperature gas chromatography: quick detection of new compounds

Further lipophilic flavonols present in Vellozia graminifolia have been determined by high temperature high resolution gas chromatography (HTHRGC) and by HTHRGC coupled to mass spectrometry (MS). These methods resulted in the detection, isolation and characterisation of a monoisoprenylated flavonol 3,5,4′‐trimethoxy‐3′‐hydroxy‐6,7‐(2″‐isopropenyldihydrofurano)flavone from the ethyl acetate extract of the whole plant. The structural elucidation was accomplished using spectral data, including two‐dimensional NMR, and on chemical transformations. Both HTHRGC and HTHRGC‐MS were shown to be alternative and extremely valuable methods for the quick screening of flavonoid aglycones and other chemical metabolites of the Velloziaceae. Copyright © 2001 John Wiley & Sons, Ltd.