Polyphenols of Quercus robus L. : II. Preparative isolation by low-pressure and high-pressure liquid chromatography of heartwood ellagitannins

Heartwood of Quercus robur L. contains about 10% (w/w), of hexahydroxydiphenoyl esters (ellagitannins). Five of the most abundant hexahydroxydiphenoyl esters were purified by a combination of chromatography on Sephadex LH-20 and high-performance reversed-phase liquid chromatography. Two of them were identified as castalagin and vescalagin.