Photodynamic inactivation of Candida tropicalis biofilms by parietin, a natural dihydroxyanthraquinone

J. MARIONI; LAURA MUGAS, M.; NÚÑEZ MONTOYA, SUSANA C.; BORSARELLI, CLAUDIO D.

Viña del Mar

Encuentro; XIV ENCUENTRO LATINOAMERICANO DE FOTOQUIMICA Y FOTOBIOLOGIA; 2019

USACH

The 1,8-dihydroxy-3-methoxy-6-methylanthraquinone (Parietin, PTN), a blue-light absorbing pigment present in several lichens of the genus Teloschistes spp., shows photosensitizing properties through both Type I (superoxide anion, O2?-) and Type II (singlet molecular oxygen, 1O2) mechanism, with antibacterial effects in vitro when it was photo-stimulated [1]. The aim of this work was to evaluate the in vitro antifungal activity of PTN, analyzing whether this effect could be increased by actinic irradiation, and establishing if the photoinactivation mechanism involves the production of Reactive Oxygen Species (ROS).PTN was isolated from the lichen Teoloschistes nodulifer (Nyl.) Hillman (Teloschistaceae) and it was purified by recrystallization from the acetone extract, and its purity was determined by HPLC. Minimum Inhibitory Concentration (MIC) of PTN was determined by following the protocols of the Clinical and Laboratory Standards Institute [2], testing twelve concentrations (0.24 to 500 μg/mL) in planktonic cultures of Candida tropicalis NCPF 3111 (103 cells/mL). PTN aqueous solution (ethanol as co-solvent