Characterization of sulfated quercetin and epicatechin metabolites

Montserrat Dueñas, Susana González-Manzano, Felipe Surco-Laos, Ana González-Paramas, Celestino Santos-Buelga

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26 Scopus citations


Different monosulfates of quercetin and epicatechin with metabolic interest were obtained by hemisynthesis and characterized regarding their chromatographic behavior and absorption and mass spectra. Three of these compounds were further isolated, and their structures were elucidated by mass spectrometry and 1H and 13C nuclear magnetic resonance using one- and two-dimensional techniques (heteronuclear single-quantum coherence and heteronuclear multiple-bond correlation). The calculation of the proton and carbon shifts caused by sulfation allowed for the assignment of the position of the sulfate group in the flavonoids, so that the compounds were identified as quercetin-3′-O-sulfate, quercetin 4′-O-sulfate, and epicatechin 4′-O-sulfate. It was found that sulfation at position 3′ induced a large upfield shift in the carbon bearing the sulfate group and downfield displacements of the adjacent carbons, whereas no significant upfield or downfield shifts were observed with respect to the parent flavonoid when sulfation was produced at position 4′.

Original languageEnglish
Pages (from-to)3592-3598
Number of pages7
JournalJournal of Agricultural and Food Chemistry
Issue number14
StatePublished - 11 Apr 2012
Externally publishedYes


  • NMR
  • Quercetin
  • epicatechin
  • metabolites
  • sulfates


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