The effect of flavonoids on rat heart mitochondrial function

In this study the effects of flavonoids (quercetin and its derivatives as rutin, hyperoside, quercitrin) on the oxidative phosphorylation in rat heart mitochondria were investigated. We found that all investigated flavonoids possessed uncoupling activity. Thus, quercetin, rutin, and quercitrin in dose-dependent manner induced a stimulation of the State 2 respiration rate by 10-110% with pyruvate + malate as substrate. The maximal stimulation of the State 2 respiration rate was obtained at 1.08 ng/ml of quercetin, 15.2 ng/ml of hyperoside and 44.4 ng/ml of rutin. Quercitrin had clearly lower effects. The State 3 respiration rate was also affected by flavonoids. Quercetin (from 1.08 ng/ml), hyperoside (from 10 ng/ml) and rutin (from 60 ng/ml) caused the decrease in State 3 respiration rate by 16-51%. We assume, that partial mitochondrial uncoupling (without affecting the State 3 respiration rate) induced by flavonoids could have a cardioprotective effect, and that mitochondria could be involved in the mechanism of this process.