EN
Modified ABTS cation radical decolorization assay and EPR technique were applied to screen the antioxidant activity of three flavonoids with different polarity: 7-O-β-[2-O-feruloyl-β-glucuronopyranosyl (1→2) glucuronopyranoside] (tricine), 4'-methoxy-5,7-dihydroxyflavone 6-C-β-glucopyranoside (isocytisoside) and I 3' II 8 biapigenine (amentoflavone), with nonpolar all-trans β-carotene used as standard carotenoid molecule. The ABTS [2,2'- azino-bis(3-ethylbenzthiazoline-6-sulphonic acid] cation radical decolorization assay was modified as follows: (1) measurements extended up to 8 days after preparation, (2) method adapted for flavonoids with different polarity and β-carotene, (3) concentrations in the 0.01-10 μM range of both trolox and antioxidants in order to use the same experimental conditions for both this technique and EPR measurement.