Dietary supplementation of old mice with flavonoid dihydroquercetin causes recovery of the mitochondrial enzyme activities in skeletal muscles

The effect of a potent antioxidant, flavonoid dihydroquercetin on the activity of three mitochondrial enzymes in mouse skeletal muscles has been investigated. An ability of this substance to restore the activity of mitochondrial enzymes in old animals was demonstrated. The activities of citrate synthase, NADHcoenzymeQ1-oxidoreductase (complex 1) and cytochrom c -oxidase (complex 4) were assessed using spectro-photometric analysis in a quadriceps muscle homogenate. It was shown that the citrate synthase activity decreased moderately and the activities of complexes 1 and 4 in skeletal muscles dropped significantly in old mice. Supplementation of drink water with dihydroquercetin for a few weeks led to an increase of citrate synthase and complex 1 activity ( P < 0.1) in muscles of old animals. Activity of complex 4 returned to the level found in the tissue of young mice. Maximal activity of citrate synthase and complex 1 was found in muscles of young mice. Sensitivity of NADH-coenzymeQ1-oxidoreductase to a specific inhibitor rotenone differed in all three groups of mice. Young and old mice exhibited about 95% and 84% of the total sensitivity, respectively, while in old mice receiving dihydroquercetin the sensitivity of complex 1 to the inhibitor increased up to 98%. The biochemical alterations entailed an increase in animals’ mobility as well as an improvement of fur and skin condition. Fatty acid composition of homogenate in muscle tissue of all three groups was also investigated. A reliable decline of the amount of linoleic acid and an increase in stearic and docosanoic acid contents as well as an increase of total amount of fatty acids in muscles of old mice were found. Statistically significant changes in fatty acid composition in muscles of old mice in the control group and in old mice receiving antioxidant were not observed.