INVESTIGADORES
THOMAS Andres Hector
congresos y reuniones científicas
Título:
Peroxidation of soybean phosphatidylcholine liposomes photoinduced by pterin
Autor/es:
MARIANA VIGNONI; ANGEL CATALA; ANDRÉS H. THOMAS
Lugar:
Córdoba
Reunión:
Congreso; 16th International Congress on Photobiology; 2014
Institución organizadora:
International Union of Photobiology
Resumen:
Lipid peroxidation process is thought to be involved
in many physiological and pathological events [1]. Many model membranes can be
used to learn more about issues that cannot be studied in biological membranes.
Sonicated liposomes prepared with soybean phosphatidylcholine (SoyPC) were
submitted to lipid peroxidation, under air atmosphere at room temperature, with
pterin (Ptr) as initiator. Pterins are heterocyclic compounds widespread in
nature and have been previously identified as good photosensitizers under UVA
irradiation [2,3].
In this work, we have investigated the ability of Ptr
(50-250μM), the parent compound of oxidized pterins, 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. Peroxidation of SoyPC (260 µM) resulted in
an increase in conjugated dienes production, reaching a maximum at around 50
min and then decreasing. When lipid peroxidation was performed in the absence
of Ptr a significant smaller production of conjugated dienes, after a lag of e.a. 30 min, was observed. Also, mass
spectrometry measurements were performed to identify peroxidation products.
As a conclusion, steady UVA irradiation of solutions
containing Ptr and SoyPC led to the lipid 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.
[1] A.
Catalá, Chemistry and Physics of Lipids,
2009, 157, 1.
[2]
G. Petroselli, M. L. Dántola, F. M. Cabrerizo, A. L. Capparelli, C. Lorente, E.
Oliveros, A. H. Thomas, J. Am. Chem.
Soc., 2008, 130, 3001.
[3] A.
H. Thomas, C. Lorente, K. Roitman, M. M. Morales,M. L. Dántola, J. Photochem. Photobiol. B, 2013, 120, 52.