PTERIN ENHANCE LIPID PEROXIDATION OF SOYBEAN PHOSPHATIDYLCHOLINE LIPOSOMES UNDER UVA LIGHT

MARIANA VIGNONI; ANDRES H. THOMAS; ANGEL CATALA

Rosario

Congreso; Reunion Anual SAIB 2014; 2014

SAIB

Sonicated liposomes prepared with soybean phosphatidylcholine (SoyPC) were submitted to lipid peroxidation, under air atmosphere at RT, with pterin (Ptr) as initiator. Pterins are heterocyclic compounds widespread in nature and have been previously identified as good photosensitizers under UVA irradiation. In this work, we have investigated the ability of Ptr to photosensitize the oxidation of SoyPC in aqueous solutions under UVA irradiation. Conjugated dienes and trienes, determined by absorption at 234 and 270 nm respectively were measured as a function of time. Lipid peroxidation of SoyPC resulted in an increase in conjugated dienes production, reaching a maximum at around 50 min and then decreasing. In the absence of Ptr a significant smaller production of conjugated dienes, after a lag of 30 min, was observed. Mass spectrometry measurements were performed to identify peroxidation products. As a conclusion, steady UVA irradiation of solutions containing Ptr and SoyPC led to peroxidation of polyunsaturated fatty acids, whereas the Ptr concentration remained unchanged. Ptr showed a clearly enhanced effect on peroxidation rate and steady state concentration of oxidation products. This model constitutes a useful system to study formation of lipid peroxidation intermediaries and products in an aqueous environment to determine the effect of Ptr as photoinducers.