Flavonoids from Polygonum hydropiper L.(Polygonaceae)

Five flavonoids along with -sitosterol were isolated from the leaves of Polygonum hydropiper L. (Polygonaceae). Four flavonoids were identified as quercetin, quercetin-3-O- -L- rhamnoside (quercitrin), quercetin-3-sulphate and (+)-catechin. Their structures were established on the basis of chemical evidence and spectroscopic techniques, including 2D NMR methods.