Kinetics of Antioxidant Activity of α-Tocopherol and Some of Its Homologues: Part 1. Review: Theoretical Model

Resumo

The first part of the theoretical study devoted to the description of the kinetics and mechanism of the lipid peroxidation process involving the complexes of cytochrome c and cardiolipin with account for the effect of an antioxidant is presented. The main components of the ROS (reactive oxygen species) and AOD (antioxidant defense) systems and their properties are considered. The key features of the activity of these systems and various channels of the influence of their components on each other, both intrasystemic and intersystemic, important for the optimal interaction of these systems in the organism, are discussed. Special attention is paid in the review to the experimental works where the properties and structure of the cytochrome c and cardiolipin complexes of various types, along with their peroxidase activity, are studied. In addition to two known ways to control the peroxidase activity of these complexes discussed in the literature, it is proposed to consider another way, which is connected with a possibility to include the lipophilic antioxidant molecules into the composition of the complexes under study. The proposed way to regulate the peroxidase activity, increasing the effectiveness of the peroxidase process control, opens up new opportunities to regulate the process of the apoptosis of cells. Based on the analysis of experimental works on this problem, a theoretical kinetic model of the peroxidase process is formulated, which includes two reaction pathways: an enzymatic pathway involving the complexes of cytochrome c and cardiolipin and a non-enzymatic pathway involving free radicals. A system of differential equations that describes the kinetics of the lipid peroxidation process is constructed with account for the inhibiting effect of the antioxidant. The obtained model system of the kinetic equations will be used to study and compare the antioxidant activity of vitamin E (α-tocopherol) and some of its homologues with a shortened side chain, relying on the available theoretical and experimental data.