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Updated: Sep 25, 2026

Biosynthesis of a Flavonol from a Flavanone by Establishing a One-pot Bienzymatic Cascade
Published on: August 14, 2019
Characterization of a colorless anthocyanin-flavan-3-ol dimer containing both carbon-carbon and ether interflavanoid
Sophie Remy-Tanneau1, Christine Le Guernevé, Emmanuelle Meudec
1INRA-UMR Sciences pour l'OEnologie, 2 Place Viala, 34060 Montpellier, France.
Abstract:
Direct addition of anthocyanins and flavan-3-ols was investigated in a model system by incubating malvidin 3-glucoside and (-)-epicatechin in ethanol. Analysis of reaction products by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC/ESI-MS) before and after thiolysis showed the formation of colorless dimers detected at m/z 781 in the negative ion mode, with retention times and spectroscopic characteristics identical to those of compounds detected in wine, which contain one malvidin 3-glucoside unit and one flavanol unit. On the basis of their resistance to thiolysis, these compounds were postulated to be bicyclic dimers linked with both carbon-carbon and ether bonds as observed in the case of A type proanthocyanidins. The major dimer analyzed by NMR experiments was identified as malvidin 3-glucoside(C2-O-C7,C4-C8)epicatechin, confirming this hypothesis. A similar assay was performed with (+)-catechin instead of (-)-epicatechin, and the formation of bicyclic dimers was also observed.
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