Antifungal effect by tetracationic phthalocyanines on Candida albicans

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

Congreso; 2da Reunion Conjunta Sociedades de Biologia; 2011

2da Reunion Conjunta Sociedades de Biologia

The resistance of C. albicans has been increasing even against traditional antifungal agents. The photodynamic inactivation (PDI) has been proposed for the elimination of microorganisms. In this treatment, the sensitizer is accumulated in microbial cells, which in the presence of light are inactivated by the formation of cytotoxic species. In this work were studied the spectroscopic, photodynamic properties and the PDI of C. albicans sensitized by Zn(II)2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]phthalocyanine (ZnPyPc4+) and Zn(II)2,9,16,23-tetrakis(N,N,N-trimethylamine) phthalocyanine (ZnAmPc4+). Both sensitizers presented a singlet molecular oxygen production of ~0.6. The cultures treated with 10 ìM of ZnPyPc4+ and ZnAmPc4+ for 30 min of incubation showed a binding of ~4.80 and ~0.17 nmol/106 cells, respectively. The amount of cell-bound sensitizer diminished with the number of washing steps. Cell survival after irradiation was dependent on the concentration used and the dose of light, producing a decrease of 5 log at 10 ìM ZnPyPc4+ and 30 min of illumination, while the inactivation was lower in cultures treated with ZnAmPc4+. Moreover, this activity of ZnPyPc4+ was also confirmed by the delay in the growth curve. Studies indicate that ZnPyPc4+ presents potential applications as phototherapeutic agent for the inactivation of yeast by PDI.