Effect of (+)-catechin on rat heart mitocondria

IGLESIAS DE; BOMBICINO SS; BOVERIS A; VALDEZ LB

Buenos Aires

Congreso; VI International Conference on Polyphenols and Health; 2013

Flavonoids are low molecular weight phenolic compounds with a quinonoid-like chemical structure. They have been shown to attenuate the progression of diseases associated with oxidative stress and mitochondrial dysfunction. Mitochondria are the main sources of intracellular reactive oxygen and nitrogen species. The aim of this work was to study the effect of (+)-catechin, a flavan-3-ol, on mitochondrial bioenergetics. Isolated mitochondria from rat heart were incubated in the absence or in the presence of (+)-catechin (3 nM to 100 uM). (+)-Catechin, in uM range (10 µM; ~50 nmol catechin/mg protein), reduced (25%) state 3 O2 consumption sustained by malate and glutamate, but not the state 4 respiration rate. (+)-Catechin concentrations lower than 1 uM did not modify mitochondrial O2 uptake. However, (+)-catechin in nM range (10 nM; ~150 pmol catechin/mg protein) inhibited NO (50%) and H2O2 (45%) production rates. Moreover, the flavonoid diminished the state 4 mitochondrial membrane potential by about 10 mV, when malate-glutamate were used as substrates. These results show that nM concentration of (+)-catechin reduces mitochondrial membrane potential leading to a decline in mtNOS activity and H2O2 production rate, according to the inhibitory effect of flavonoids on complex I activity (Lagoa et al., 2011).