[Antioxidant activity of natural and synthetic quinones].

Antioxidation activity (AOA) of ubiquinone (Q10), phylloquinone (vitamin K1), menadione as well as of the newly synthesized analogues of vitamin K1--N-derivatives of 2-methyl-3-aminomethyl 1.4-naphthoquinone, producing autocomplexes with intramolecular transfer of electrons, was studied in the model system of the methyl oleate initiated oxidation. The menadione AOA was shown to be 2-fold higher as compared with the inhibitory activity of natural quinones. Activity of AK-40 and AK-49, artificial analogues of vitamin K1, was higher 2.6-fold than that of ubiquinone and phylloquinone and 1.4-fold higher than menadione activity. At the same time, AOA of ubiquinone and phylloquinone was 1.5-fold lower than the tocopherol activity, while naphthoquinones AK-40 and AK-49 were 2-fold more active as compared with tocopherol but their activity was 2-fold lower than ionol. Mechanism of natural and synthetic quinones action as well as properties of their long chain analogues are discussed.