OXIDATIVE DAMAGE-INDUCED BY A NOVEL PORPHYRIN IN TUMOR MITOCHONDRIA AND OTHER MODEL SYSTEMS - POTENTIAL APPLICATIONS IN PHOTODYNAMIC THERAPY

With a view to locate new porphyrins for use in PDT, we have evaluated the ability of a novel water soluble porphyrin, o-tetrakis[4-(carboxy methyleneoxy)phenyl]porphyrin (T4CPP) to induce photodamage in membran es and nucleic acids using rat hepatic and tumour mitochondria and pla smid pBR322 DNA as model systems. T4CPP, when exposed to visible light , induced significant lipid peroxidation and enzyme inactivation in mi tochondria and single strand breaks in plasmid pBR322 DNA. Analysis of the products of peroxidation and selective inhibition by specific inh ibitors and effect of deuteration showed that the oxidative damage ind uced was mainly due to singlet oxygen (O-1(2)) and partly due to other reactive species. Copyright (C) 1997 Elsevier Science Ltd.