Mechanism of photodynamic action induced by a cationic phthalocyanine on Candida albicans cells

M. ALBANA DI PALMA, A. LAURA OCHOA, M. GABRIELA ÁLVAREZ, M. ELISA MILANESIO, EDGARDO N DURANTINI

Encuentro; XI Encuentro Latinoamericano de Fotoquímica y Fotobiología; 2012

Fungal diseases represent a critical problem to health and they are one of the main causes of morbidity and mortality worldwide. Candida albicans is the most common species associated with candidiasis and is the most frequently recovered species from hospitalized patients. The search for new therapeutic approaches is stimulated by the fact that standard drug treatments are prolonged and the appearance of drug resistant strains is more frequent in high risk groups. The photodynamic inactivation (PDI) has been proposed for the elimination of microorganisms. In this treatment, the photosensitizer is accumulated in microbial cells, which in the presence of light are inactivated by the formation of cytotoxic species. Basically, the photosensitizer excited state can react with molecules from its direct environment by electron or hydrogen transfer, leading to the production of radicals, or the photosensitizer can transfer its energy to oxygen, generating the highly reactive singlet molecular oxygen, O2(1Dg). In this work, the photodynamic mechanism of action induced by zinc(II) 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]phthalocyanine (ZnPPc+4) was studied in C. albicans.