Structure elucidation of peonidin 3,7-o-β-diglucoside isolated from Garnacha Tintorera (Vitis vinifera L.) grapes

Red wines made from Garnacha Tintorera grapes (also known as Alicante Bouschet and one of the few so-called teinturier Vitis vinifera grape cultivars, because its berry flesh is also red-colored) are usually blended with other red wines as a natural way for enhancing the color intensity of red wines. The phenolic composition of Garnacha Tintorera grapes showed already described interesting features such as the occurrence of unusual anthocyanins (pelargonidin-based anthocyanins and a peonidin dihexoside) that had not been previously described in V. vinifera cultivars. The isolation and further structure elucidation (GC-MS analysis of sugar moieties, UV-vis, LC-MS(n), and (1)H and (13)C NMR spectroscopic data) have allowed the identification of the aforementioned peonidin dihexoside as peonidin 3,7-β-O-diglucoside. This peonidin derivative, in combination with the previously reported pelargonidin-type anthocyanins, can be suggested as a suitable chemical marker for this singular V. vinifera grape cultivar and the wines made totally or partially from this grape cultivar.