Extracellular hydrolytic enzymes production of susceptible and fluconazole-resistant Candida albicans after photodynamic therapy

Abstract

Curcumin (CUR) is a pigment extracted from Curcuma longa L. with great potential as a photosensitizer for photodynamic inactivation of oral biofilms. However its low solubility in aqueous solutions is a challenge. In order to indicate this therapy for clinical use with adequate efficacy and safety, the investigation of biocompatible vehicles able to solubilize the CUR retaining its photodynamic effect is required. In this context, the first step is to investigate the photodynamic behavior of new formulations. This study assessed the photodegradation of CUR at two concentrations (60 and 80 M) prepared in different vehicles (Oleic Acid, Chitosan and Emulgin). Aliquots of each formulation were transferred to 96 well plates and illuminated for 1, 2, 3, 4, 5,10, 15, 20, 25 and 30min with a blue LEDs system ( =440nm, I=0.022mW/cm2). After each illumination time, a measure of the absorbance spectra of the formulations was taken. Photobleaching rates were calculated and it was concluded that, for any formulation tested, the maximum illumination time should be of 15min because after that there will be noCURavailable to continuepromotingphotodynamic effect. Thus, the most stable formulation was the one prepared with chitosan (80 M).