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Nadezhda
V. Zhdanova, Natalya Yu. Lotosh, Evgeny A. Kulikov, Svetlana V. Lukashevich, Sergey N. Malakhov, Yuriy A. Koksharov, Alla A. Selishcheva
Interaction of astaxanthin with iron salts Fe2+
and Fe3+ in organic solvents
Abstract
Abstract. The carotenoid astaxanthin
has a variety of biological activities and antioxidant properties. Due to its
lipophilic nature, astaxanthin can be used to protect against lipid
peroxidation, in which iron ions play an important role. The effect of Fe2+
ions on the oxidative degradation of astaxanthin in phospholipid liposomes was
previously studied. In this work, we studied the interaction of astaxanthin
with Fe3+ and Fe2+ in organic solvents of various
polarities in the absence of lipids. It has been shown that in the presence of
Fe3+, astaxanthin oxidation and degradation occurs in methanol and
dichloromethane. The formation of an intermediate product with an absorption
maximum at 876 nm was recorded spectrophotometrically. Electron paramagnetic
resonance (EPR) proved the radical nature of the intermediate product, the
signal intensity of which decreased over time, with the signal remaining for up
to three days. Based on the obtained results, it can be assumed that the
radical product formed during the reaction with Fe3+ is the radical
cation of astaxanthin. At the same time, no changes were detected when astaxanthin
was incubated with Fe2+: the absorption spectrum did not change and
no radical product was formed.
Key words: astaxanthin, ferric,
ferrous, HPLC, oxidative degradation, radicals, EPR
Copyright (C) Chemistry Dept., Moscow State University, 2002
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