title: Phthalocyanine thio-pyridinium derivatives as antibacterial photosensitizers.
abstract: This study describes the synthesis of three new tetra- and octa-thio-pyridinium phthalocyanine derivatives. PSs 3a and 4a were prepared from the tetramerization of phthalonitriles 1 and 2, respectively, whereas PS 5 was prepared from the nucleophilic substitution of the 8 beta fluor atoms of hexadecafluorophthalocyaninatozinc(II) by mercaptopyridine, followed by cationization. The recombinant bioluminescent Escherichia coli strain was used to assess, in real time, the photoinactivation efficiency of these cationic phthalocyanines, under white and red light. The cellular localization and uptake were also determined to assess the potential of the new phthalocyanines as antibacterial agents. Derivative 3a was the most effective PS, causing a 5 logs reduction in bioluminescence after 30 min of irradiation under white or red lights. The photoinactivation efficiency of the phthalocyanine 4a was similar (5 logs reduction in bioluminescence) to that of 3a when irradiated with white light, but the efficiency of inactivation was reduced (2.1 logs reduction in bioluminescence) under red light. The tetra-substituted phthalocyanine 3a also generates high amounts of singlet oxygen, does not aggregate in PBS and is highly fluorescent, which makes it an effective PS and a promising fluorescent labeling.
authors.affiliation: Department of Chemistry and QOPNA, University of Aveiro, Aveiro, Portugal.
authors.forename: Joana B
authors.initials: JB
authors.lastname: Pereira
authors.forename: Eliana F A
authors.initials: EF
authors.lastname: Carvalho
authors.forename: Maria A F
authors.initials: MA
authors.lastname: Faustino
authors.forename: Rosa
authors.initials: R
authors.lastname: Fernandes
authors.forename: Maria G P M S
authors.initials: MG
authors.lastname: Neves
authors.forename: José A S
authors.initials: JA
authors.lastname: Cavaleiro
authors.forename: Newton C M
authors.initials: NC
authors.lastname: Gomes
authors.forename: Angela
authors.initials: A
authors.lastname: Cunha
authors.forename: Adelaide
authors.initials: A
authors.lastname: Almeida
authors.forename: João P C
authors.initials: JP
authors.lastname: Tomé
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects; D007211:Indoles / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D054833:Isoindoles; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D017319:Photosensitizing Agents / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D011726:Pyridinium Compounds / Q000737:chemistry / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000900:Anti-Bacterial Agents; D007211:Indoles; D054833:Isoindoles; D017319:Photosensitizing Agents; D011726:Pyridinium Compounds; C013647:phthalocyanine