5, 6-Dihydropyranobenzopyrone: a previously undetermined antioxidant isolated from Polygonum amplexicaule / 中国天然药物

ABSTRACT

AIM@#To study the chemical constituents and their bioactivity of Polygonum amplexicaule.@*METHODS@#The isolation of compounds was achieved by chromatographic techniques and structure of the isolates was established by UV, IR, HRESI-MS and NMR including 1D and 2D experiments.@*RESULTS@#Bioassay-guided fractionation of an ethanolic extract of Polygonum amplexicaule led to the isolation of a hitherto unidentified compound, 5, 6-dihydropyranobenzopyrone (1) along with nine previously known compounds (2-10). Compounds 2-10 were identified as amplexicine (2), catechin (3), rutin (4), quercetin-3-O-β-D-galactopyranoside (5), chlorogenic acid (6), galloyl glucose (7), caffeic acid (8), gallic acid (9) and scopletin (10).@*CONCLUSION@#Compound 1 is new. Compounds 1-10 exhibited considerable antioxidant activity in a 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay.