Chemical constitutents from flowers of Stellera chamaejasme and their antioxidant activity / 中草药

ABSTRACT

Objective: To investigate the flavonoids and lignans from the flowers of Stellera chamaejasme and their structure-activity relationship (SAR) of antioxidant activity. Methods: The compounds were isolated by column chromatography and HPLC packed with macroporous resin, silica gel, and Sephadex LH-20. Their structures were elucidated by spectroscopic analysis. Their anti-oxidant activities in vitro were evaluated by DPPH, ABTS, and FRAP assays. Results: Twelve compounds were isolated from the flowers of S. chamaejasme, and identified as artemisetin (1), quercetin (2), isoscutellarein-8-O-β-D-glucuronopyranoside (3), quercetin-3-O-β-D- glucopyranoside (4), astragalin (5), hypolaetin-8-O-β-D-glucuronopyranoside (6), kaempferol 3-O-β-D-glucopyranosyl-(1→2)-O-α- L-xylopyranoside (7), rel-(3R,3'S,4R,4'S)-3,3',4,4'-tetrahydro-6,6'-dimethoxy [3,3'-bi-2H-benzopyran]-4,4'-diol (8), matairesinol (9), uralenol (10), cycloastragenol (11), and (+)-pinoresinol (12). Conclusion: Compounds 1, 3, 5-7, and 10 are isolated from this plant for the first time, and compounds 2, 4, 5, and 10 showed significant antioxidant activity, and the SAR analysis suggested that the glycosylation at the C-8 or C-3 position of flavonoids could weaken their antioxidant activity.