Characterization of Stilbene Composition in Grape Berries from Wild Vitis Species in Year-To-Year Harvest.

Asian and American Vitis species possess a strong potential for crossbreeding programs, owing to their several resistance properties. Stilbenes are phenolic compounds present in grape berries and are well-known for their main role as phytoalexins and resistance to biotic stresses in plants. However, their identification and quantification in grape berries from wild Vitis remains unexplored. A mass spectrometry multiple reaction monitoring method combined with the analysis of pure standards allowed for the unambiguous characterization of 20 stilbenes in the grape berry skin extracts of nine native Vitis species and one cultivated Vitis vinifera species (cv. Cabernet Sauvignon). A main occurrence of monomeric (Z-piceid, E-piceid, E-isorhapontin, and E-astringin), dimeric (E-ε-viniferin, Z-ε-viniferin, and pallidol), and oligomeric (isohopeaphenol and r-viniferin) stilbenes was highlighted. Some stilbenes were clearly characterized for the first time in grape berries, such as the dimers ampelopsin A, E-vitisinol C, and parthenocissin A as well as the tetramers r2-viniferin and r-viniferin. Stilbene composition and content varied widely among several Vitis species and vintage years.