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S. O. Alyaseva, N. Y. Lotosh, A. V. Kamaev, A. I. Kulebyakina, A. A. Selischeva
Antioxidant effect of α-lipoic acid on phosphatidylcholine oxidation caused by fenton
reaction
Abstract
By the method of mass spectrometry with the
negative electrospray ionization mode the presence of both
monomers and dimers and also trimers of LA was established in the aqueous
phase. At incubation of LA with ferrous ions (0.1 mM) in the positive electrospray ionization mode
the appearance of new mass-ions – 261, 467, 727 – was found; in the
negative electrospray ionization mode the mass-ion 671 was
detected. These ions are complexes of LA with ferrous ions formed by the coordination
bonds.
The presence of the complexes depended on the LA concentration: at 0.25–4 mM
the presence of all four complexes was observed. At 0.06 mM only 261 complex
was formed. By IR spectroscopy it was established that in Fenthon reaction one
or both sulfur atoms in the LA molecule are oxidized by the hydroxyl radical.
These results allow to consider two mechanisms of antioxidants properties of
LA: the oxidation by the hydroxyl radical and ferrous ions chelation.
Key words:α-lipoic acid, antioxidant, complexation, IR spectroscopy, lipid
peroxidation, iron chelation, ferrous ions.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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