[Study on the chemical constituents of the active fraction of Polygonum capitatum].

OBJECTIVE: To investigate the chemical constituents of the active fraction of Polygonum capitatum. METHODS: Various preparative chromatographic techniques were used for the isolation and purification of the compounds in the flavonoid-enriched fraction and their structures were determined by comparison of their physicochemical and chromatographic data with those of the authentic samples and spectral analysis. RESULTS: Fourteen compounds were obtained and identified as 1-O-P-D-(6'-O-galloyl)-glucopyranosyl-3-methoxy-5-hydroxybenzene (1) ,5,7-dihydroxy-4H-chromen-4-one (2), ellagic acid (3), myricetrin (4), hirsutine (5), rutin (6), quercetin-3-O-(2"-O-galloyl)-beta-D-glucopyranoside (7) , quercetin-3-O-( 3"-O-galloyl) -/3-D-glucopyranoside (8), quercitrin (9) , kaempferol-3-O-alpha-L-rhamnopyranoside (10), quercetin-3-O-(2"-O-galloyl) -alpha-L-rhamnopyranoside (11), quercetin-3-O-(3"-O-galloyl) -alpha-L-rhamnopyranoside (12), quercetin (13), kaempferol (14). CONCLUSION: The flavonoid-enriched fraction contains flavonols and their glycosides as its major components,which might be responsible for the biological effects of Polygonum capitatum. Compounds 1, 8 and 12 are isolated from the genus Polygonum for the first time; Compound 3 is isolated from Polygonum capitatum for the first time.