Fluorescence properties and singlet oxygen quantum yield of Parietin, an anthraquinone derivative isolated from Teleoschistes flavicans

L.R. COMINI, S.C. NÚÑEZ MONTOYA, MARIONI J, J.L. CABRERA; F.E. MORAN VIEYRA, R.A. MIGNONE, C.D. BORSARELLI.

Córdoba

Congreso; 16th INTERNATIONAL CONGRESS ON PHOTOBIOLOGY; 2014

IUPB, Facultad Ciencias Químicas, UNC

For several years, some anthraquinone (AQs) derivatives have been extensively studied in relation to their photosensitizing properties in photodynamic reactions [1,2]. Thus, some of them showed good antibacterial and antiviral effects in vitro, by means of a photosensitization mediated by reactive oxygen species (ROS) such as superoxide anion (O2.¯), hydroxyl radical (OH.) and singlet molecular oxygen (1O2), with the subsequent oxidative damage [3, 4]. This time we report the purification and identification of parietin (PTN), an AQ isolated from vegetal specie: Teleoschistes flavicans (SW) Norm. (Telochistaceae). In addition, the spectroscopic properties of the pigment in CHCl3 as solvent, indicate that PTN absorbs blue light and shows almost 3% of fluorescence efficient with a remarkable Stokes shift of 70 nm and non-exponential fluorescence decay, suggesting a possible excited-state tautomeric keto-enol or charge-transfer intramolecular equilibrium.