Stilbene from Polygonum cuspidatum

Two glycosides of stilbene dimer, 33 and 34 were isolated from Polygonum cuspidatum. Pharmacological studies showed that 34 which has a special skeleton showed moderate inhibition (inhibition rate 36%) in the formation of MDA at a concentration of 2 pM [21]. 

Xiao K, Xuan LJ, Xu YM, Bai DL, Zhong DX, Wu HM, Wang ZH, Zhang NX (2002) Dimaic stilbene glycosides from Polygonum cuspidatum. European J Oig Chem 3 564—568... 

Some simple stilbenes isolated from the roots of Polygonum cuspidatum (Polygonaceae) showed moderate inhibitory activity of the bovine thymus P56 " tyrosine kinase activity, when angiotensin 1 was used as a substrate. The most potent were resveratrol (26) and its cis form obtained by photochemical isomerisation. Both compounds showed similar potency against rat brain PKC, whereas resveratrol monoglucosides were less active [81]. 

Maximol A (528) which had earlier been synthesized from the roots of Rheum maximowiczii, has now been confirmed as a natural product [241 and references therein]. Two dimeric stilbene glucosides (531, 532) have been isolated from the root of Polygonum cuspidatum. Compound 532... 

Recently, two glycosides of stilbene dimer named compound 1 (33) and compound 2 (34) were obtained from an aqueous extract of the roots of Polygonum cuspidatum. Among them, 34 was a new type of resveratrol dimer possessing a four-membered ring [21]. 

Jayasuriya et al. [11] and Jayatilak et al. [60] isolated several stilbene compounds from the methanol fraction of Polygonum cuspidatum roots. The isolated compounds included /rans-resveratrol (15), /rans-piceid (16), /nm -resveratrol-04-p-glucoside (17), cw-resveratrol (18), cw-piceid (19) and c/s-resveratrol-04-p-glucoside (20). Yan et al. also isolated 2,3,4 -5-tetrahydroxystilbene-2-O-P-D-glucoside (21) from P. panjutinii species [37]. 

Protein tyrosine kinases are enzymes that catalyze the transfer of phosphate from adenosine triphosphate (ATP) to the hydroxyl group of the amino acid tyrosine on many essential proteins. These proteins play an essential role in cell signalling, regulation of cell growth and transformation of the cells [10]. The identification of specific inhibitors of protein tyrosine kinase may uncover potential anticancer agents [10]. Jayatilak et al. [60] investigated the kinase inhibitor activity of stilbene compounds, 15-20, that were extracted from the polar methanol fraction of Polygonum cuspidatum roots. The compounds were evaluated in protein... 

Extracts from the roots of Polygonum cuspidatum were analyzed for stilbenes (piceatannol glucoside, resveratroloside, piceid, resveratrol). These compounds were well resolved on at C,8 column (k = 254 nm) using a 15/85/0.15/0.85 acetonitrile/ water/triethylamine/formic acid mobile phase [1257], Elution was complete in 21 min and detected levels of 1-6 mg/g were reported. 

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