Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

A new flavonol glycoside, namely 3-(alpha-rhamnopyranosyl-(1 -> 2)-[beta-xylopyranosyl-(1 -> 6)]-beta-glucopyranosyloxy) isorhamnetin was reported from methanol extracts of aerial parts of Suaeda fruticosa for the first time. In this work, liquid chromatography coupled to atmospheric pressure chemical ionisation mass spectrometry, high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy were used to identify this new compound. Structure was elucidated on the basis of extensive spectroscopic analysis, including HSQC, HMBC and H-1-H-1 COSY. Antioxidant potentialities of a pure compound were evaluated. The estimation of antioxidant capacities using oxygen radical absorbance capacity (ORAC method) and a cell based-assay (WS1) indicated that this new flavonol exhibited the highest antioxidant activities with an ORAC value of 5.0 +/- 0.3 mu mol Trolox/mu mol and inhibited the t BH-induced oxidation of 2',7'-dichlorofluorescin with an IC50 value of 4.9 +/- 0.6 mu M.