title: Genotoxic effect of photodynamic therapy mediated by curcumin on Candida albicans.
abstract: Photodynamic therapy (PDT) is a promising method for localized and specific inactivation of fungi and bacteria. A nontoxic light-sensitive compound is taken up by cells, which are then exposed selectively to light, which activates toxicity of the compound. We investigated the potential of sublethal PDT using light-sensitive curcumin (CUR) in combination with blue (455 nm) light to promote reactive oxygen species (ROS) formation in the form of singlet oxygen and DNA damage of Candida albicans. Surprisingly, CUR-mediated PDT but also light alone caused significantly longer comet tails, an indication of DNA damage of C. albicans when compared with the negative control. The intracellular ROS production was also significantly higher for the group treated only with light. However, PDT compared to blue light alone significantly slowed DNA repair. Comet tails decreased during 30 min visualized as a 90% reduction in length in the absence of light for cells treated with light alone, while comet tails of cells treated with PDT only diminished in size about 45%. These results indicate that complex mechanisms may result in PDT in a way that should be considered when choosing the photosensitive compound and other aspects of the treatment design.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, São Paulo State University-UNESP-Rua Humaitá, nº 1680-CEP: 14801-903, Araraquara, SP, Brazil.
authors.forename: Juliana Cabrini
authors.initials: JC
authors.lastname: Carmello
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, São Paulo State University-UNESP-Rua Humaitá, nº 1680-CEP: 14801-903, Araraquara, SP, Brazil.
authors.forename: Ana Cláudia
authors.initials: AC
authors.lastname: Pavarina
authors.affiliation: Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Oliveira
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal bjorn_johansson@bio.uminho.pt.
authors.forename: Björn
authors.initials: B
authors.lastname: Johansson
mesh_terms: D002176:Candida albicans / Q000187:drug effects* / Q000528:radiation effects; D020552:Comet Assay; D003474:Curcumin / Q000494:pharmacology*; D004249:DNA Damage / Q000187:drug effects* / Q000528:radiation effects; D004271:DNA, Fungal / Q000187:drug effects* / Q000528:radiation effects; D008027:Light; D009153:Mutagens / Q000494:pharmacology*; D010778:Photochemotherapy / Q000379:methods; D017319:Photosensitizing Agents / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000032:analysis
chemical_list: D004271:DNA, Fungal; D009153:Mutagens; D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; D003474:Curcumin
keywords: fungi; genotoxicity; photoinactivation; photosensitizer agent