Resumen:
Since several years anthraquinone (AQs) derivatives have been thoroughly studied in relation to their
photosensitizing properties in photodynamic reactions [1,2]. On the basis of this, some of them showed
good antibacterial and antiviral effects, by photosensitization of reactive oxygen species (ROS) such as
superoxide anion (O2
.¯), hydroxyl radical (OH.) and singlet molecular oxygen (1O2), with 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 efficiency 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. The main results are summarized as follows.
Additionally, we performed time-resolved detection of singlet oxygen luminescence at 1270 nm by 355
nm laser pulsed excitation (7 ns fwhm) and by using phenalen-1-one as reference compound the singlet
molecular oxygen quantum yield. F 0.8 was determined, indicating that this AQs derivative shows
good photosensitizing properties, which can be associated with its potential photodynamic activity .
References
[1] I. Gutiérrez, S.G. Bertolotti, M.A. Biasutti, A.T. Soltermann, N.A. García. Can. J. Chem. 1997, 75,
423.
[2] K. Gollnick, S. Held, D.O. Mártire, S.E. Braslavsky. J. Photochem. Photobiol. A: Chem. 1992, 69,
155.
[3] K. Zerdin, M.A. Horsham, R. Durham, P. Wormell, A.D. Scully. Reac.Funct.Polymers.2009, 69, 821.
[4] Z. Luksiené. Food Technol. Biotechnol.2005, 43, 411.