C_(13)-Norisoprenoid Aglycon Composition of Leaves and Grape Berries from Muscat of Alexandria and Shiraz Cultivars

摘要

C_(13)-norisoprenoid glycoconjugates from Muscat of Alexandria and Shiraz leaves and grape berries isolated through adsorption on Amberlite XAD-2 resin were subjected to enzymatic hydrolysis and the released aglycons were analyzed by GC-MS. C_(13)-norisoprenoids were more abundant in the leaves than in the berries. Differences were observed with regard to the C_(13)-norisoprenoid pattern between leaves and berries. 3-Hydroxy-β-damascone, a major aglycon of grape berry C_(13)-norisoprenoid glycosides, was not detected in the leaves. Compositional differences were also observed between Muscat and Shiraz leaves. 3-Oxo-α-ionol, and its retro derivatives were more abundant in Muscat than in Shiraz leaves. Conversely, Shiraz leaves were richer in 7,8-dihydroionone derivatives, such as megastigmane-3,9-diol and 3-oxo-7,8-dihydro-α-ionol.