On the interaction between anthralin and mitochondria: a revision.

Anthralin is an inhibitor of oxidative phosphorylation at concentrations found in vivo. ADP-stimulated oxygen consumption is diminished. Consequently, the rate of ATP synthesis is reduced and mitochondrial ATP content declines. Neither the isolated ATPase (F1F0-ATPase), nor the mitochondrial membrane-bound ATPase are influenced by the drug. Respiration under resting conditions is not affected. The experimental data unequivocally indicate that anthralin is not an uncoupler of oxidative phosphorylation, as previously stated. Furthermore, the interpretation that respiratory deficiency induced in yeast strains by anthralin is a consequence of petite mutations has to be reconsidered. Under in vivo conditions, anthralin inhibits respiration per se. Our experiments, including the electron spin resonance spectroscopy, reveal that anthralin alters mitochondrial membrane structure and function simultaneously. A redox or free-radical mediated step may be involved. In consequence, inhibition of ATP production occurs which may become the limiting factor for increased cellular metabolism in psoriasis.