Inhibition by secalonic acid D of oxidative phosphorylation and Ca2+-induced swelling in mitochondria isolated from rat livers.

The in vitro biological activity of secalonic acid D, a mycotoxin from Aspergillus ochraceus, was studied to assess its cytotoxicity for isolated rat liver mitochondria. Secalonic acid D uncoupled the oxidative phosphorylation of mitochondria and caused a mild inhibition of state 3 respiration. Secalonic acid D weakly enhanced latent ATPase activity in mitochondria but suppressed 2,4-dinitrophenol-stimulated ATPase activity. Secalonic acid D did not induce pseudoenergized swelling of mitochondria and markedly inhibited the Ca2+-induced swelling of mitochondria in KCl isotonic solution.