The uncoupling action of skyrin and the involvement of 6, 6'-hydroxyl groups in the uncoupling action on mitochondrial respiration

Abstract

Effects of anthraquinone pigments, skyrin and emodin, on mitochondrial reactions have been compared. Both pigments exhibited the uncoupling effects on oxidative phosphorylation of isolated rat liver mitochondria, accompaning a weak inhibition on state 3 respiration. Emodin exhibited much stronger uncoupling effect than that of skyrin. O-methylated derivatives of skyrin and emodin at 6, 6'-and 6-hydroxyl group, respectively, did not uncouple mitochondrial respiration, indicating the involvement of these phenolic hydroxyl groups in the uncoupling actions on the oxidative phosphorylation of mitochondria. Skyrin induced mitochondrial swelling in KCl isotonic solution. Whereas emodin die not induce. These results indicate that biological properties of skyrin, which has dimer structure of emodin, and emodin are of some differences from each oter.