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Phenolics from grapes and wines can play a role against oxidation and development of atherosclerosis. Stilbenes have been shown to have cancer chemopreventive activity and to protect lipoproteins from oxidative damage. A method for the direct determination of stilbene oligomers (viniferin and pallidol) as well as astilbin in different types of wine using high-performance liquid chromatography with UV detection is described. In a survey of 21 commercial wines from the south of France, levels of pallidol and viniferin are reported for the first time in different types of wines. Viniferin was found to be present only in red and botrytized sweet white wines with levels between 0.1 and 1.63 mg/L; pallidol was not found in dry and sweet white wines but only in wines made by maceration with stems, with levels between 0.38 and 2.22 mg/L. Highest levels of astilbin were found in Egiodola (15.13 mg/L), Merlot (11.61 mg/L), and Cabernet Sauvignon (8.24 mg/L) for red wines and in Sauvignon (5.04 mg/L) for white varietal wines. Astilbin levels are highest for recent vintages, but pallidol is not found in older vintages. During noble rot development in Sauvignon or Sémillon grapes from the Sauternes area, levels of trans-astringin, trans-resveratrol, trans-piceid, and pallidol are quite low (<0.5 mg/kg of grapes). Viniferin and astilbin levels become optimum at 2 and 30 mg/kg, respectively, during spot grape and speckle grape stages.

Vitis vinifera cells grown in vitro respond to methyl jasmonate (MeJa) with enhancement of phytoalexin accumulation. MeJa added during the first half of the exponential growth phase increased the intracellular accumulation of stilbenes, mainly (Z)- and (E)-piceid (3,5,4‘-trihydroxystilbene-3-O-β-glucoside), in strains grown in either maintenance medium or polyphenol inductive medium. Plant cell cultures were used to produce isotopically (13C) labeled stilbenes by addition of 13C phenylalanine at different time intervals and in various concentrations. Incorporation of 13C phenylalanine into stilbenes was measured by EA-IRMS, and three successive 2-mM phenylalanine additions provided the best result (66%). This allowed production of 13C labeled Vitis vinifera phenolic compounds for investigation of their absorption in humans.

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