Food: Young shoots of Japanese knotweed are plump and juicy with reddish-colored sheath and triangular leaves and are delicious edible treat. Young plant tastes like sorrel, the shoots are high in antioxidant Resveratrol, which helps to lower bad cholesterol and prevent heart attacks. The plant is an excellent source of vitamin A, vitamin C, the antioxidant flavonoid Rutin, potassium, phosphorus, zinc, and manganese. (Brill) It’s close relative, Giant Knotweed, is a lager variety, and is also edible. No poisonous lookalikes has been reported.
Medicine: In traditional Chinese medicine, it is known as Huzhang or “tiger stick.” As a concentrated source of resveratrol, the plant has anticancer, anti-inflammatory, blood sugar-lowering and other beneficial cardiovascular effects. (Elliott P.J.) Resveratrol may delay the onset of Alzheimer’s disease or slow its progression. Also, it activates sirtuin genes, which increase cell longevity the same way a calorie-restricted diet does. (Brill)
The roots of Japanese knotweed are used in traditional Chinese and Japanese herbal medicines as a natural laxative. The active ingredient responsible for the laxative effect is emodin, effective in doses of 20 to 50 mg per day.
Sources: For current distribution map visit http://plants.usda.gov/java/profile?symbol=pocu6
“Micronutrient Information Center: Resveratrol”. Linus Pauling Institute at Oregon State University.