RESVERATROL SHOWS BENEFICIAL EFFECTS IN ULCERATIVE COLITIS: Resveratrol is a plant compound similar to flavonoids. It is found in the low levels of the skin of red grapes, red wine, cocoa powder, baking chocolate, dark chocolate, peanuts and mulberry skin. Red wine is perhaps the most recognized source of resveratrol, however, red wine contains only one milligram per glass. Most resveratrol supplements use Japanese knotweed (Polygonum cuspidatum) as the source.