Characterization of the interaction of polyphenols with model membranes. Effects upon viscosity and protection against oxidative agents

DE ATHAYDE MONCORVO, A; MORERO, R; MINAHK, C

Villa Carlos Paz, Cordoba

Congreso; XLII Reunión Anual Sociedad Argentina de Biofisica; 2013

Polyphenols are secondary metabolites commonly found in a wide variety of plants and vegetable-origin aliments, characterized by the presence of two or more phenolic groups. These substances are subject of great interest in the last years, due to their potential multiple bio-active features, including their well-known antioxidant capacity. Importantly, a widely accepted characteristic about polyphenols is their ability to interact with biological membranes. For the present study, four polyphenols from different chemical families (resveratrol, naringenin, epigallocatechin gallate and enterodiol) were tested for their effect on membrane viscosity by fluorescence techniques. For that purpose, liposomes of dipalmitoyl phosphatidylcholine (DPPC) alone or in combination with 40% cholesterol were prepared by extrusion and labeled with either laurdan, DPH or TMA-DPH. Anisotropy was measured at different temperatures. On the other hand, protection against oxidative agents such as hydrogen peroxide and Cu II was spectrophotometrically studied following the increase of conjugated dienes. Fluorescence studies showed that the presence of polyphenols induced a marked increase in the viscosity with a concomitant alteration in the order of the phospholipids, which was polyphenol-dependent. On the other hand, all compounds tested were able to decreased the oxidation levels induced by the Fenton reaction. However, little correlation was found with the membrane interaction inferred from anisotropy measurements. Results presented in this work indicate that polyphenols are able to closely interact with biological membranes. Therefore, further studies in this area would result in a better understanding of the potential uses beyond their anti-oxidant properties.