title: Influence of charge and metal coordination of meso-substituted porphyrins on bacterial photoinactivation.
abstract: The photodynamic effect of meso-substituted porphyrins with different charges and metal ions: meso-tetraphenylporphyrin tetrasulfonate 1, its nickel 2 and zinc complexes 3; meso-tetranaphthylporphyrin tetrasulfonate 4, and its zinc complex Zn 5; and tetra piridyl ethylacetate porphirins 6 and their nickel 7 and zinc 8 complexes, were synthesized and studied their antimicrobial activity against Escherichia coli. Fluorescence quantum yields (ΦF) were measured in water using reference TPPS4, obtaining higher values for complexes 3 and 4. The singlet oxygen ΦΔ were measured using histidine as trapping singlet oxygen and Rose Bengal as a reference standard. Complexes 1, 2 and 6 have the highest quantum yields of singlet oxygen formation, showing no relation with the peripheral charges and efficiency as Type II photosensitizers. Meanwhile complexes 3, 8 and 4 were the most efficient in producing radical species, determined with their reaction with NADH. The photoinduced antibacterial activity of complex was investigated at different concentrations of the photosensitizers with an irradiation time of 30 min. The higher antibacterial activities were obtained for the complexes 1-3 that are those with greater production of ROS and minor structural deformations. Complexes 7 and 8 had moderate activity, while 4-6 a low activity. Thus, in this work demonstrates that the production of ROS and structural deformations due to peripheral substituents and metal coordination, influence the activity of the complexes studied. Therefore, is important to perform comprehensive study physics and structurally when predicting or explain such activity.
authors.affiliation: Laboratorio de Fotoquímica, Centro de Química, Instituto Venezolano de Investigaciones Científicas I.V.I.C., Apartado 20632, Caracas 1020-A, Venezuela. Electronic address: tzoltan@ivic.gob.ve.
authors.forename: Tamara
authors.initials: T
authors.lastname: Zoltan
authors.affiliation: Laboratorio de Fotoquímica, Centro de Química, Instituto Venezolano de Investigaciones Científicas I.V.I.C., Apartado 20632, Caracas 1020-A, Venezuela.
authors.forename: Franklin
authors.initials: F
authors.lastname: Vargas
authors.affiliation: Laboratorio de Fotoquímica, Centro de Química, Instituto Venezolano de Investigaciones Científicas I.V.I.C., Apartado 20632, Caracas 1020-A, Venezuela.
authors.forename: Verónica
authors.initials: V
authors.lastname: López
authors.affiliation: Laboratorio de Bioquímica Celular, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas I.V.I.C., Apartado 20632, Caracas 1020-A, Venezuela.
authors.forename: Valery
authors.initials: V
authors.lastname: Chávez
authors.affiliation: Laboratorio de Fotoquímica, Centro de Química, Instituto Venezolano de Investigaciones Científicas I.V.I.C., Apartado 20632, Caracas 1020-A, Venezuela.
authors.forename: Carlos
authors.initials: C
authors.lastname: Rivas
authors.affiliation: Laboratorio de Biología de virus, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas I.V.I.C., Apartado 20632, Caracas 1020-A, Venezuela.
authors.forename: Álvaro H
authors.initials: ÁH
authors.lastname: Ramírez
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D004583:Electrons; D004926:Escherichia coli / Q000187:drug effects* / Q000528:radiation effects; D008027:Light; D008163:Luminescent Measurements; D008670:Metals / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects* / Q000528:radiation effects*; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D026082:Singlet Oxygen / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D008670:Metals; D011166:Porphyrins; C409084:tetraphenylporphyrin; D026082:Singlet Oxygen; D000255:Adenosine Triphosphate
keywords: Escherichia coli; Metal and charge effect; Photoinactivation; Reactive oxygen species; Water-soluble metallic porphyrins