Novel monoterpene diols and diol glycosides in Vitis vinifera grapes

The beta -D-glucopyranoside and the 6-O- alpha arabinofuranosyl- beta -D-glucopyranoside of (E)-2,6-dimethylocta-2,7-diene-1,6-diol were isolated from Vitis vinifera cv. Riesling grape juice and their structures determined by spectral methods. Additionally, the diastereoisomeric 3,7-dimethylocta-1,6-diene-3,5-diols and (E,E)-2,6-dimethylocta-2,6-diene-1,8-diol were identified for the first time in grapes, and these three diols together with (E)- and (Z)-2,6-dimethylocta-2,7-diene-1,6-diol were quantified both as free monoterpenes and as glycosides in the juice of eight grape varieties.