Chantal Castagnino

Preparative isolation of polyphenolic compounds from Vitis vinifera by centrifugal partition chromatography

This study deals with a centrifugal partition chromatography developed for the separation of phenolic compounds from Vitis vinifera. EtOAc grape seed extracts were separated using the solvent system hexane-ethyl acetate-ethanol-water (1:8:2:7; v/v) in two fractions: one containing about 75% of flavanol monomers (catechin and epicatechin) corresponding to 18% of crude extract and another fraction B-type dimers (22% of crude extract). From the stalk extracts, we could separate stilbenoid compounds (resveratrol and its oligomers; 12% of crude extract) which were eluted in less than 30 min from flavanols (which required a few hours of additional elution). Using the same solvent system but in different ratios (4:5:3:3; v/v), we isolated the trans-resveratrol (7@1000; 90% purity).

Castavinol, a New Series of Polyphenols from Bordeaux Red Wines

A series of polyphenols with a new skeleton, named castavinol, has been isolated from Bordeaux red wines. The structural elucidation of these three natural products was achieved by UV, MS, IR, NMR 1H and 13C spectroscopies. The most probable pathway for their biogenesis and chemical properties related to the colour modification upon ageing of wines are given.