Guaranteed Potency. Japanese Knotweed. Green Screened. Triple Strength Resveratrol is intended to provide nutritive support for cardiovascular health. Resveratrol is one of a group of compounds that are produced in plants during times of environmental stress. Resveratrol a compound most commonly associated with red grape skins is also found in the roots of Japanese knotweed. It is intended to provide nutritive support as an antioxidant.