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Giant knotweed is widely grown throughout Japan and is foraged as a wild edible vegetable. The root of Polygonum cuspidatum, were widely used in traditional Chinese and Japanese medicine. It is also known to be a rich source of resveratrol, which is a natural polyphenol. Emodin, physcion, citreorosein, rhein, fallacinol, questin, phenylpropanoides , polyphenols, and tannins are major active components present in this root.