Generation of free radicals by photoexcitation of pheophorbide alpha, haematoporphyrin and protoporphyrin.

An investigation of the production of radical species by photoexcitation pheophorbide alpha, haematoporphyrin and protoporphyrin was performed. In an aqueous solution containing different amounts of ethanol, the superoxide radical was detected by the spin trapping technique. In addition, secondary radicals were observed. The generation of oxygen radicals was found to dominate in solutions with a low ethanol content.