Superoxide anion radical (O2) generation by adriamycin and anthraquinone analogues.

The reduction of ferricytochrome c with adriamycin in phospate buffered saline (pH 7.4) and alkaline solution was obsereved spectrophotometrically. The reduction increased gradually with time of incubation, and decreased with the addition of superoxide dismutase. The semiquinone radical derived from adriamycin was detected by electron spin resonance spectrometer. Superoxide production by analogous compounds of adriamycin was examined. The cytotoxicity caused by anthraquinone antibiotics is discussed on the basis of molecular structure.