The interaction of flavonoids with membranes: potential determinant of flavonoid antioxidant effects

ERLEJMAN A.G.; FRAGA C. G.; OTEIZA P.I.

Ciudad de Buenos Aires, Argentina.

Congreso; XII Biennial Meeting of the International Society for Free Radical Research; 2004

International Society for Free Radical Research

Twenty four flavonoids and related substances including flavanones, flavanols and procyanidins, flavonols, isoflavones, phenolic acids and phenylpropanones were investigated by their effects on lipid oxidation, membrane fluidity, and membrane integrity. Flavanols, their related procyanidins, and flavonols were the most active preventing lipid oxidation initiated by the lipid-soluble 2,2’-azobis (2,4-dimethylvaleronitrile) (AMVN). A positive and significant correlation was observed between the capacity of the flavonoids to inhibit AMVN-initiated TBARS formation and both, to prevent Triton X-100-induced membrane disruption (r: 0.74, p < 0.003) and to change lipid ordering at the level of the membrane polar head groups (r: 0.50, p < 0.01). However, the mentioned parameters did not correlate when the initiator of the oxidation was the water-soluble 2,2’-azo-bis (2-amidinopropane) (AAPH). Results indicate that, from the tested compounds, the more hydrophilic flavonoids (flavanols, procyanidins and flavonols) have the highest interaction with the polar head groups of phospholipids at the lipid-water interface of membranes providing protection against lipid oxidation. The capacity of flavonoids to interact with the membrane surface should be considered among the factors contributing to their antioxidant properties in hydrophobic domains. This work was supported by grants from the University of Buenos Aires (BO54 and B052); CONICET (PIP 0738/98 and 02120); and ANPCyT (PICT 01-08951), Argentina.