tailieunhanh - 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. | Journal of Chemistry Vol. 42 4 P. 512 - 515 2004 FLAVONOIDS FROM POLYGONUM HYDROPIPER L. POLyGONACEAE Received NGUyEN VAN DAU vu NHUAN THANG Faculty of chemistry Hanoi University of Science VNU SUMMARy Five flavonoids along with f-sitosterol were isolated from the leaves of Polygonum hydropiper L. Polygonaceae . Four flavonoids were identified as quercetin quercetin-3-O-a-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. I - INTRODUCTION Many species of the genus Polygonum Polygonaceae are used in traditional medicine against kidney stones and as antidiabetic diuretic and antidiarrhoeal agents 1 . The genus Polygonum produces a wide range of secondary metabolites including flavonoids anthraquinones naphthoquinones sesquiterpen-oids lignans coumarins stilbene glycosides phenol carboxylic acids and so on 2 . Polygonum hydropiper L. is a small herb 30 - 60 cm in height which widely distributes in Europe and Asia. It grows wild in wet lowland areas along canals pools fields etc. There are few papers reported on Polygonum hydropiper L. showing the presence of sesquiterpenes dialdehydes polygodial and warburganal which exhibit antifeedant antimicrobial plant growth inhibitory cytotoxic and pesticidal activities together with several related drimane-type sesquiterpenes. In addition other kinds of metabolites are also found such as tri-p-coumaryl glucoside from the roots antioxidative sulphated flavonoids from the leaves etc 3 4 . In the course of a chemical examination of flavonoids in Polygonum hydropiper L. we now report the isolation and identification of four flavonoids quercetin quercetin-3-a-L-rhamnoside quercitrin quercetin-3-sulphate and -catechin from the leaves of Polygonum hydropiper L. II - EXPERIMENTAl 1. General experimental procedures UV spectra were determined in spectroscopic grade MeOH on a Shimadzu UV-VIS .