ELLAGITANNINS IN WOODS OF SESSILE OAK AND SWEET CHESTNUT DIMERIZATION AND HYDROLYSIS DURING WOOD AGEING

Article abstract of DOI:10.1016/S0031-9422(00)89647-8

Monomeric and dimeric C-glucosidic ellagitannins and phenolic acids were studied by reverse-phase HPLC and gel permeation chromatography in various sapwood and heartwood samples of sessile oak (Quercus petraea) and sweet chestnut (Castanea sativa).Sessile oak differs from sweet chestnut by the presence in heartwood of pentose-substituted ellagitannins.Analysis of ellagitannin concentrations and a model experiment show that vescalagin is a common precursor of all dimers which are likely formed by a non-enzymatic reaction.Ellagic acid and gallic acid in oak and chestnut woods result, respectively, from the hydrolysis of ellagitannins and some unknown galloyl esters.Both dimerization and hydrolysis occur at the sapwood-heartwood transition and in the dead heartwood.