Figure 2.

Biflavonoids inhibit low-density lipoprotein (LDL) oxidation. Oxygen radical absorbance capacity (ORAC) values of the biflavonoids Mo, Vo, and Fu (10 µM) were determined and expressed as micromole equivalents of Trolox per mol of biflavonoid to be compared with that of the monoflavonoid quercetin (Qu; 10 µM) (A). ORAC value was also determined for the BF (5.5 µg/mL) and expressed as micromole equivalents of Trolox per gram to be compared with pure biflavonoids (B). The effect of biflavonoids (10 µM for Mo, Vo, and Fu and 5.5 µg/mL for BF) on the Cu²⁺-induced formation of the lipid peroxidation product malondialdehyde in the LDL particle was assessed by TBARS assay (C). Given the protective activity of biflavonoid preparations on LDL lipid peroxidation, a titration experiment of biflavonoids at the indicated concentrations (μM for Mo, Vo, and Fu; μg/mL for BF) on the electronegativity of the apolipoprotein fraction in the LDL was also determined by the REM assay in agarose gels (D). Also, a comparison of the protective effect of low concentration (1.5 µM for Mo, Vo, and Fu, and 0.83 µg/mL for BF) biflavonoids on REM was performed with samples run in the same agarose gel (E). Note that the biflavonoid Mo alone does not have prooxidant effect [last line in (D)] under the experimental conditions used. Results are representative of at least three independent experiments.