Inhibitory effects of several anthracyclines on mitochondrial respiration and coenzyme Q10 protection.

A set of three novel anthracyclines, active as antitumour agents, has been examined for their possible effects on rat heart mitochondrial respiration. The in vitro inhibiting effects of the compounds have been compared with that of the older doxorubicin. Aclacinomycin was generally more inhibitory than doxorubicin, 4'-epi-doxorubicin and 4'-epi-tetrahydropyranyl-adriamycin, with both succinate and NAD+-linked substrates. Attempts to prevent anthracycline from inhibiting the succinate oxidase activity by means of adding exogenous coenzyme Q10 gave encouraging results, the inhibiting effect being in fact reduced.