ON THE PHOTOINACTIVATION MECHANISM OF CANDIDA TROPICALIS BIOFILM BY NATURALLY- OCCURRING ANTHRAQUINONES

JULIANA MARIONI; ROGER BRESOLÍ-OBACH; MONTSERRAT AGUT; LAURA R. COMINI; JOSÉ L. CABRERA; MARÍA G. PARAJE; SANTI NONELL ; SUSANA C. NÚÑEZ MONTOYA

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2017 vol. 12

1932-6203

bstractThe photoprocesses involved in the photo-induced Candida tropicalis biofilm reduction bytwo natural anthraquinones (AQs), rubiadin (1) and rubiadin-1-methyl ether (2), were examined.Production of singlet oxygen (1O2) and of superoxide radical anion (O2·−) was studied.Although it was not possible to detect the triplet state absorption of any AQs in biofilms,observation of 1O2 phosphorescence incubated with deuterated Phosphate Buffer Solution,indicated that this species is actually formed in biofilms. 2 was accumulated in the biofilm toa greater extent than 1 and produced measurable amounts of O2·− after 3h incubation in biofilms.The effect of reactive oxygen species scavengers on the photo-induced biofilm reductionshowed that Tiron (a specific O2·− scavenger) is most effective than sodium azide (aspecific 1O2 quencher). This suggests that O2·− formed by electron transfer quenching ofthe AQs excited states, is the main photosensitizing mechanism involved