Sonochemistry of antitumor quinones in argon-saturated aqueous solutions: enhanced ferricytochrome c reduction

Sonolysis of argon-saturated aqueous antitumor quinone solutions resulted in an enhancement in ferricytochrome c (Cyt c) reduction. Partial inhibition of these reduction enhancements by addition of superoxide dismutase evidences the production of superoxide ions. No correlation between quinone hydrophobicity or redox potential is observed in the extent of Cyt c reduction. The semiquinone of the parent quinone as well as other quinone-derived reductants are proposed as the electron shuttle intermediates which reduce Cyt c.