Applications of pulse radiolysis and flash photolysis to some problems related to chemistry of cancer therapy

The semireduced form of the anti-tumour agent adriamycin is implicated in cardiotoxis side effects. The drug used in photodynamic therapy was measured by observations of the phosphorescence emission at 1270 nm. The measurements suggest that the most active component, dihaematoporphyrin ether or ester, is comparatively ineffective in itself photodynamically, but may serve as a pool for the more effective haematoporphyrin and hydroxyethylvinylporphyrin to act inside the cancer cell. One-electron oxidation of dopa, or photoionization leads to the melanin precursor dopachrome via dopasemiquinone and dopaquinone. The latter reacts with cysteine to form cysteinyldopa, a marker for malignant melanoma metastasis. (author)