Flavonoids were extracted from cranberry powder with acetone and ethyl acetate and subsequently fractionated with Sephadex LH-20 column chromatography. The fraction eluted with a 60% methanol solution was composed primarily of phenolic constituents with maximum absorbance at 340 nm. A high-performance liquid chromatography procedure was developed, which resolved 22 distinct peaks with UV/vis and mass spectra corresponding to flavonol glycoside conjugates. Six new constituents not previously reported in cranberry or in cranberry products were determined through NMR spectroscopy to be myricetin-3-β -xylopyranoside, quercetin-3-β-glucoside, quercetin-3-α -arabinopyranoside, 3′-methoxyquercetin-3-α-xylopyranoside, quercetin-3-O-(6″-p-coumaroyl)-β-galactoside, and quercetin-3-O-(6″-benzoyl)-β-galactoside. Quercetin-3-O-(6″ -p-coumaroyl)-β-galactoside and quercetin-3-O-(6″-benzoyl)-β -galactoside represent a new class of cranberry flavonol compounds with three conjugated components consisting of a flavonol, sugar, and carboxylic acid (benzoic or hydroxycinnamic acids). This is also the first report identifying quercetin-3-arabinoside in both furanose and pyranose forms in cranberry. Elucidation of specific flavonol glycosides in cranberry is significant since the specificity of the sugar moiety may play a role in the bioavailability of the flavonol glycosides in vivo.
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences(all)
- Acylated quercetin-3-glycosides
- Flavonol glycosides
- Vaccinium macrocarpon Ait.