Parietin: an efficient photo-screening pigment in vivo with good photosensitizing and photodynamic antibacterial effects in vitro

LAURA COMINI, , , ; F. EDUARDO MORÁN VIEYRA; RICARDO A. MIGNONE; M. LAURA MUGAS; PAULINA PÁEZ, ; JOSÉ LUIS CABRERA; SUSANA NÚÑEZ MONTOYA ; CLAUDIO D. BORSARELLI

Photochemical and Photobiological Sciences

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2017 p. 201 - 201

1474-905X

he photophysical, photoinduced pro-oxidant and antibacterial properties in vitro of the natural occurringparietin (PTN; 1,8-dihydroxy-3-methoxy-6-methyl-9,10-anthraquinone) were evaluated. PTN wasextracted from the lichen identified as Teloschistes flavicans (Sw.) Norm. (Telochistaceae). Results indicatethat in chloroform solution, PTN presents spectroscopic features corresponding to an excited-state intramolecularproton-transfer (ESIPT) state with partial keto?enol tautomerization. In argon-saturated solutions,the singlet excited state is poorly fluorescent (ΦF = 0.03), decaying by efficient intersystem crossingto an excited triplet state 3PTN*, as detected by laser-flash photolysis experiments. In the presence oftriplet molecular oxygen, the 3PTN* was fully quenched producing singlet molecular oxygen (1O2) with aquantum yield of 0.69. In addition, in buffer solutions, PTN has the ability to also generate a superoxideradical anion (O2?−) in a human leukocyte model and its