Resveratrol transformation in red wine after heat treatment.

Resveratrol is a well-known wine constituent. Its concentration can vary according to the cultivar choice and the winemaking process. Due to its phenolic structure, resveratrol could be transformed under high temperature or oxidative conditions, leading to the formation of various derivatives including oligomers. Hence, the goal of this study is to investigate the presence of these derivatives in wine. In the first stage, hemisynthesis of oligomeric stilbenes was achieved from resveratrol in ethanol by oxidative coupling using metals. Four de novo synthetized resveratrol derivatives were identified by MS and NMR spectroscopy including two new molecules, oxistilbenin F and oxistilbenin G. In the second stage, analysis of red wine after heat treatment by LC-MS confirmed the presence of some of these compounds in wine. Finally, the anti-inflammatory effects of the compounds were evaluated by studying their ability to prevent lipopolysaccharide (LPS)-induced upregulation of nitric oxide (NO) and reactive oxygen species (ROS) production in RAW 264.7 macrophage cell line.