Photoinactivation of Candida albicans cultures sensitized by free-base and metallo chlorins

PAULA CORDERO; MARIA GABRIELA ALVAREZ; EDWIN J. GONZÁLEZ; DANIEL A. HEREDIA; EDGARDO N. DURANTINI

Conferencia; 8th International Electronic Conference on Medicinal Chemistry.; 2022

Candidemia is the most common form of invasive infections and affects with high mortality rates in older people and premature children. In particular, Candida albicans has several virulence factors that facilitate yeast colonization in humans. In this sense, photodynamic inactivation of microorganisms is a promising new alternative to eliminate fungal infections. Herein, the photodynamic effect of a free-base chlorin and its metal complexes with Zn(II) and Pd(II) were investigated in C. albicans under different culture conditions. A decrease in cell survival of more than 5 log was found in planktonic cells incubated with 5 microM chlorin upon 15 min of white light irradiation. Studies varying the effect of medium and in the presence of reactive oxygen species scavenges indicated that a type II photodynamic mechanism of action was predominant in yeast inactivation. These chlorins were also effective to photoinactivate C. albicans pseudohyphae suspended in PBS, producing a reduction of 6 log after 5 min of irradiation. Furthermore, the biofilms of C. albicans that incorporated the chlorins during the proliferation stage were completely photoinactivated. The results allow optimizing the best conditions to inactivate C. albicans under different culture conditions.