Photophysical and photosensitizing characterization of 5-chloro-soranjidiol obtained from Heterophyllaea lycioides.

DIMMER JESICA; COMINI LAURA; MORAN VIEYRA EDUARDO; MIGNONE RICARDO; NUÑEZ MONTOYA SUSANA; REY VIRGINIA; MENDOZA CATHERINE SONIA; CABRERA JOSE LUIS; BORSARELLI CLAUDIO

Córdoba

Congreso; 16TH INTERNATIONAL CONGRESS ON PHOTOBIOLOGY; 2014

International Union on Photobiology

Heterophyllaea J.D. Hook. (Rubiaceaea) is a South American genus represented by only two species, Heterophyllaea pustulata Hook f. and Heterophyllaea lycioides (Rusby) Sandwith [1]. Our research group succeeded in the identification of nine AQs from the first species. We demonstrated that these AQs possess photosensitizing properties and these results led us to study them as anticancer and antimicrobial agents to be used in photodynamic therapy, obtaining satisfactory results [2]. Recently we have started with the phytochemical study of H. lycioide and we have identified five AQs at the moment: four previously isolated from H. pustulata and an additional new one, 5-Chloro-Soranjidiol, recently described for this family of compounds [3]. The aim of this work is to determine photophysical and photosensitizing properties of 5-Chloro-Soranjidiol compared with those of the parent compound (Soranjidiol, previously isolated from H. pustulata) using steady-state and time-resolved absorption and emission spectroscopies. The main results are summarized as follows. The results indicate that both compounds have similar photophysical properties, with a 3-exponential fluorescence decay component with a remarkable Stokes shift, probably by presence of several emitting states due to the formation of tautomeric species by intramolecular H-transfer, favoring non-radiative decay processes. However, the  for both compounds was similar and relatively efficient (0.25), confirming the potential photodynamic activity of the Soranjidiol derivatives.