Medical Attributes of Polygonum cuspidatum - Japanese knotweed  
Polygonum cuspidatum, known by the common name Japanese knotweed, is a tall, stout herbaceous perennial (Seiger, 2005) and is a member of the Polygonaceae (Seiger, 2005).  In China it is referred to as Hu Zhanz.  Japanese knotweed is also known under the scientific names Fallopia japonica and Reynoutria japonica.  The leaves are alternately arranged and are oval with pointed tips and a truncate base.  They measure approximately 15 cm long by 7.5-10 cm wide (Remaley, 2005).  Clusters of tiny white flowers are produced in the late summer, though reproduction is generally through rhizome rather than seed production (Weston et al, 2005). Knotweed is native of China, North and South Korea as well as Japan (Seiger, 2005). Outside of its point of origin, Japanese knotweed was introduced as an ornamental plant Remaley, 2005).  It is widely distributed across the United States and Canada and is found especially along rivers.  It has become established as an invasive species across Eastern Europe, Great Britain and parts of the United States (Seiger, in 1997) including Massachusetts, Connecticut, and California (USDA, 2009). Because of its presence in China, it has been mainly used primarily in Traditional Chinese Medicine as well as in Asian cultures. The rhizome has been used as an anti-inflammatory, anti-tussitive, diuretic, emmenagogue, emollient, febrifuge, stomachic (Duke & Ayensu, 1985; Usher, 1974). Extracts of the plant have shown antitumor activity within Traditional Chinese Medicine (Duke & Ayensu, 1985). Japanese knotweed contains compounds that are part of a group of organic chemicals called stilbenes, which are polyphenolic compounds attached by an ethylene (Vastano et al., 2000). The specific composition is dependent on the side chains.  One common stilbene found in Japanese knotweed is resveratrol, which is 3,5,4'-Trihydroxystilbene. Resveratrol has two isomers: cis and trans, with the latter being the most abundant.  Piceid, also known polydatin, is a glucoside form of resveratrol found in Japanese knotweed.  Emodin is an anthraquinone derivative that occurs in extracts of knotweed (Vastano et al., 2000) and other plant species. Resveratrol has been shown to have numerous effects, as assessed both in vitro and in vivo.  It decreases the viscosity of the blood and act as anticoagulant to thin blood.  Human blood was used for in vitro analysis, while rabbits were used for in vivo analysis.  This study showed that this property of resveratrol allows it to be effective in treating cardiovascular disease by reducing thrombosis and embolisms that can block arteries and lead to myocardial and cerebral infarctions (Wang et. al, 2002).  Resveratrol was successfully able to decrease platelet aggregation in patients that were resistant to aspirin.  This in vitro study showed that resveratrol could be used to help treat these high risk vascular patients (Gyorgyi, 2006).      Resveratrol can also provide inflammation relief when used in therapeutically effective amounts and combined with Devil's claw, grapeskin, and syzygium (Charters et al, 2003).  Research shows that extracts from P. cuspidatum inhibits inflammation in mouse ears in response to a topical application of 12-O- tetradecanoylphorbol-13-acetate (TPA) by inhibiting the development of edema and neutrophil infiltration, which is an essential part of the immune response.  The extract at the doses of 2.5, 1.25, and 0.3 milligrams was found to be as effective as indomethacin, a non-steroidal anti-inflammatory drug, at reducing edema (Bralley et. al, 2008).  Edema can lead to more serious complications such as congestive heart failure, so any alleviation is beneficial.   Resveratrol has been found to reduce the tumor volume, tumor weight, and lung metastasis at doses of 2.5 and 10 mg/kg in mice with highly metastatic lung carcinoma (LLC) tumors (Kimura, 2001). The inhibitory effects could not be explained b