ENHANCED ANTIRADICAL ACTIVITY OF GALLIC ACID INCLUDED IN LIPID INTERPHASES

ANDREA C. CUTRÓ; CECILIA L. SALCEDO; MARIANGELES FRIAS; MONICA NAZARENO; ANIBAL E. DISALVO

Carlos Paz

Congreso; XLII Reunion Anual de la Sociedad Argentina de Biofísica; 2013

SAB

Polyphenols are well known by its effects as antioxidant agents and by its effects on the hydration layers of lipid interphases. In this regard, it is known that gallic acid and its family are able to decrease the dipole potential and to act in water as a strong antioxidant. In this work we have studied both effects on lipid interphases in monolayers and bilayers of phosphatidylcholines. The results show that the antiradical activity of gallic acid adsorbed to DMPC membranes increases five-fold with respect to that found in water. In parallel, the gallic acid increases the negative surface charges of LUVs and decreases the dipole potential. As a result, the positively charged radical species such as ABTS+? are able to penetrate more easily the membrane, enhancing the antiradical activity. The role of interfacial water in the antiradical activity and the possible association of gallic acid with the phospholipid molecules were studied by means of surface pressure/area curves, dipole potential measures and FTIR spectroscopy. These results allow discussing the effect of interfacial water on the antioxidant reaction catalysed by lipids.