Premium
Isolation and identification of flavonoids, including flavone rotamers, from the herbal drug ‘crataegi folium cum flore’ (hawthorn)
Author(s) -
Rayyan S.,
Fossen T.,
Nateland H. Solheim,
Andersen Ø. M.
Publication year - 2005
Publication title -
phytochemical analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 72
eISSN - 1099-1565
pISSN - 0958-0344
DOI - 10.1002/pca.853
Subject(s) - chemistry , flavonols , flavanone , flavones , two dimensional nuclear magnetic resonance spectroscopy , stereochemistry , conformational isomerism , nuclear magnetic resonance spectroscopy , organic chemistry , quercetin , chromatography , flavonoid , molecule , antioxidant
Twelve flavonoids, including seven flavones, four flavonols and one flavanone, were isolated from methanolic extract of the herbal drug ‘Crataegi folium cum flore’ (hawthorn leaves and flowers) by a combination of CC (over Amberlite XAD‐7 and Sephadex LH‐20) and preparative HPLC. Their structures, including that of the novel flavonol 8‐methoxykaempferol 3‐ O ‐(6″‐malonyl‐ β ‐glucopyranoside), were elucidated by homo‐ and heteronuclear NMR and electrospray/MS. The 1 H‐ and 13 C‐NMR of all compounds, including rotameric pairs of five flavone C ‐glycosides, were assigned. The presence and relative proportion of each rotamer was shown by various NMR experiments, including two‐dimensional nuclear Overhauser and exchange spectroscopy, to depend on solvent, linkage position and structure of the C ‐glycosyl substituent. Copyright © 2005 John Wiley & Sons, Ltd.