JAPANESE KNOTWEED
Polygonum cuspidatum

Location
South of the Preclinical Science Building.  Large stands can be seen from the platform outside of Basic Science Building and the Dahlgren Medical Library.

Description
Japanese knotweed is a large, bushy plant, about four to ten feet high, with leaves that are broad, with shortpoints at the tip.  The greenish-white flowers grow in branching spikes. Flowers usually grow from leaf axils, and can be seen from summer to fall (Newcomb 1977).

History
Japanese knotweed was introduced into the New World from Eurasia (Kiple 2000).

The immature stems of Japanese knotweed are used in salads or as a cooked green (Kiple 2000).  Older stalks, peeled, can be used like rhubarb. (Elias 1982)

Current Medicinal Uses
The dried root and stem of Polygonum cuspidatum, also called Hu chang, are used in traditional Chinese medicine to treat high cholesterol and other conditions (Huang 1999). It is also used as a laxative (Lewis 1977).

Polygonum root contains resveratrol (Kimura 2001), the same beneficial phytochemical found in red wine. An aqueous extract of Polygonum cuspidatum showed anti-angiogenesis activity in vitro (Wang 2004).

Adverse Effects
Contact with Japanese knotweed can cause a light-dependent rash in some people (Elias 1982).

References
Elias TS, Dykeman PA. Field Guide to North American Edible Wild Plants. Outdoor Life Books, New York, 1982.

Huang KC. The pharmacology of Chinese herbs, 2^nd ed. CRC Press, Boca Raton, 1999: 126.

Wang S, Zheng Z, Weng Y, Yu Y, Zhang D, Fan W, Dai R, Hu Z. Angiogenesis and anti-angiogenesis activity of Chinese medicinal herbal extracts.  Life Sci.  2004 Apr 2;74(20):2467-78. 

Kimura Y, Okuda H. Resveratrol isolated from Polygonum cuspidatum root prevents tumor growth and metastasis to lung and tumor-induced neovascularization in Lewis lung carcinoma-bearing mice. J Nutr.  2001 Jun;131(6):1844-9. 

Kiple KF, Ornelas KC, ed. The Cambridge World History of Food. Cambridge University Press, Cambridge, 2000. (p. 1797)

Lewis WH, Elvin-Lewis MPF. Medical Botany: Plants Affecting Man’s Health. John Wiley & Sons, Inc., New York, 1977. (p. 284)

Newcomb L. Newcomb’s Wildflower Guide. Little, Brown and Company, Boston, 1977. (p. 190)