Flavonoid glycoside compounds from roots of Arctium lappa and structure-activity relationship of anti-oxidantion / 中草药

ABSTRACT

Objective: To investigate the flavonoid glycoside compounds from the roots of Arctium lappa and their structure-activity relationship (SAR) of anti-oxidantion. Methods: The compounds were isolated by column chromatography over silica gel, RP-C18, Sephadex LH-20, and PHPLC. Their structures were elucidated by spectroscopic analysis and their anti-oxidant activities were evaluated by DPPH, ABTS, and FRAP assays. Results: Eight flavonoid glycoside compounds were isolated from 55% ethanol extract in the roots of A. lappa, which were identified as nairutin (1), hesperidin (2), icariin (3), ononin (4), isoononin (5), neoliquiritin (6), neoisoliquiritin (7), and liquiritin (8). The anti-oxidant activities of these compounds were tested by three different methods (DPPH, ABTS, and FPAR), and their SAR were further analyzed. Conclusion: Compound 3 is isolated from the roots of A. lappa for the first time, all others were from the plants of Arctium L. for the first time; Compounds 1 and 8 have shown the strongest anti-oxidant activity; The -OH on C-3' and -OCH3 on C-4' in the B ring in regard to the anti-oxidant activity of these compounds by participating in electron delocalization and hydrogen bonding.