Free radicals induced peroxidations and isomerizations of unsaturated fatty acids

Tartaro Bujak, Ivana (2015) Free radicals induced peroxidations and isomerizations of unsaturated fatty acids. Doctoral thesis, Faculty of Science > Department of Chemistry.

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Abstract

The cause-effect relationship between free radicals in biological systems and the various pathological conditions enable us to use the radiation-chemical methods for preparation and determination these reactions under controlled conditions. In this paper we investigated polyunsaturated fatty acid radicals which are precursors for the two types of processes, peroxidation and, especially in the presence of biologically relevant thiol, cis, transisomerization of linoleic acid (LiH). A model micellar system was developed in which radical processes of LiH were selectively determined under conditions that, in contrast to the physiological, could be adapted to the experiments requirements. These two radical-induced processes were compared for the first time under biomimetic conditions demonstrating that hydroperoxides (LiOOH) and trans-lipids can be formed under oxidizing conditions. Biomimetic model was prepared with the addition of 2-mercaptoethanol as amphiphilic thiol, and radical processes initiation was performed by γ-radiation up to 400 Gy under different conditions. In air-equilibrated solutions, together with substantial amount of LiOOH (~10-5 mol dm−3), the cis, trans-isomerization process was also observed with a catalytic cycle of 370. In order to envisage the impact of self-organized supramolecular organization of LiH on the outcome of lipid peroxidation and cis, trans-isomerization processes, the influence of the micelle size and the presence of natural antioxidants were also studied.

Item Type: Thesis (Doctoral thesis)
Keywords: geometrical isomerization ; ferrous (II) ; free radicals ; γ-radiation ; lipid peroxidation ; lipid hydroperoxide ; oxidative stress ; unsaturated fatty acids
Supervisor: Mihaljević, Branka
Date: 2015
Subjects: NATURAL SCIENCES > Chemistry
Divisions: Faculty of Science > Department of Chemistry
Depositing User: mag. bibl. Ana Šafran
Date Deposited: 04 Feb 2015 13:49
Last Modified: 04 Feb 2015 13:49
URI: http://digre.pmf.unizg.hr/id/eprint/3644

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