Changes in model lipid membranes properties by presence of Caffeic Acid

GONZÁLEZ PAZ, AN; ROSA, A. SEBASTIAN; DISALVO, E. ANIBAL; FRIAS, MARÍA DE LOS A.; CEJAS, JIMENA DEL PILAR

Rosario

Congreso; L Reunión Anual de la Sociedad Argentina de Biofísica; 2022

Under pathological conditions, reactive oxygen species are produce in excess, damaging DNA, proteins, and membrane lipids. In this sense, the antioxidant activity of caffeic acid (CA) in biological membranes was reported, although the mechanisms of action and interactions are not defined. Therefore, there is great interest in the effect of antioxidants, such as phenolic acids, which prevent lipid peroxidation, on membrane properties. With this purpose, we studied the interaction of CA with dimyristoyl phosphatidylcholine (DMPC) model lipid membranes using different techniques.Surface pressure (π) and dipole potential (ψ) measurements were performed on lipid monolayers on a Langmuir balance with a vibrating plate electrode. Specific interactions between DMPC groups and CA were measured using infrared spectroscopy (FTIR-ATR). The results showed an increase in the area per molecule and a decrease in ψ in the DMPC monolayers with increasing CA concentrations. The presence of the antioxidant lowers the compressibility modulus, indicating a looser monolayer.The increase in π and ψ as a function of CA concentration can be fitted to an isotherm from which it can be inferred the existence of a positive cooperativity between CA and the monolayer residues. These specific interactions were corroborated by changes in the methylene, carbonyl, and phosphate groups bands by FTIR-ATR spectroscopy. These interactions produced a decrease in the lipid transition temperature.According to these results, it could be concluded that the mechanism of the antioxidant action of CA is related to changes in the biophysical properties of the membrane related to hydration sites of the lipid membrane.