Photodynamic inactivation of Penicillium chrysogenum conidia by cationic porphyrins.
ABSTRACT This work reports the photophysical and biological evaluation of five cationic porphyrins as photosensitizers (PS) for the photodynamic inactivation (PDI) of Penicillium chrysogenum conidia. Two different cationic porphyrin groups were synthesized from 5,10,15,20-tetrakis(4-pyridyl)porphyrin and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin. The photostability and singlet oxygen generation studies showed that these molecules are photostable and efficient singlet oxygen generators. PDI experiments of P. chrysogenum conidia conducted with 50 μmol L(-1) of photosensitiser under white light at a fluence rate of 200 mW cm(-2) over 20 min showed that the most effective PS caused a 4.1 log reduction in the concentration of viable conidia. The present results show that porphyrins 1a and 1b are more efficient PSs than porphyrin 2a while porphyrins 1c and 2b show no inactivation of P. chrysogenum. It is also clear that the effectiveness of the molecule as PS for antifungal PDI is strongly related with the porphyrin substituent groups, and consequently their solubility in physiological media. The average amount of PS adsorbed per viable conidium was a determining factor in the photoinactivation efficiency and varied between the different studied PSs. Cationic PSs 1a and 1b might be promising anti-fungal PDI agents with potential applications in phytosanitation, biofilm control, bioremediation, and wastewater treatment.
Full-textDOI: · Available from: Adelaide Almeida, Nov 05, 2014
SourceAvailable from: Mathias O. Senge[Show abstract] [Hide abstract]
ABSTRACT: This review presents an in-depth overview of the modification of porphyrins with bioconjugates and their applications in medicine today. Porphyrin bioconjugates ranging from nucleotides to steroids are under active scrutiny. However, carbohydrates have been at the forefront of such research in recent years and offer significant potential. This is attributed to their own selectivity to lectins on the surface of cancer cells and their influence on the amphiphilicity of the porphyrin macrocycle. These characteristics and the tendency of porphyrin photosensitizers to accumulate in tumor tissues make glycoporphyrins promising candidates for use as photosensitizers. Thus, a detailed overview of the synthesis and biological evaluation of glycoporphyrins is given with a particular focus on their applications in photodynamic therapy and their future prospects as drug candidates have been reported.Current Medicinal Chemistry 04/2015; DOI:10.2174/0929867322666150429113104 · 3.72 Impact Factor
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ABSTRACT: Oxidative stress induced by photodynamic treatment of microbial cells causes irreversible damages on vital cellular components such as proteins. Photodynamic inactivation (PDI) of bacteria, a promising therapeutic approach for the treatment of superficial and localized skin and oral infections, can be achieved by exciting a photosensitizing agent with visible light in an oxygenated environment. Although some studies have addressed the oxidative alterations of PDI in bacterial proteins, the present study is the first to compare the electrophoretic profile of proteins of Gram-positive and Gram-negative bacteria, with two structurally different porphyrins, which have different kinetics of photoinactivation. The cationic porphyrins 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide (Tri-Py+-Me-PF) and 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetra-iodide (Tetra-Py+-Me) were used to photosensitize Escherichia coli and Staphylococcus warneri upon white light irradiation at an irradiance of 4.0 mW cm-2. After different photosensitization periods, proteins were extracted from bacteria and analyzed by one-dimensional SDS-PAGE. Apparent molecular weights and band intensities were determined after an irradiation period corresponding to a reduction of 4 log10 in cell viability. After photodynamic treatment, there was a general loss of bacterial proteins, assigned to large scale protein degradation. Protein loss was more pronounced after PDI with Tri-Py+-Me-PF in both bacteria. There was also an increase in the concentration of some proteins as well as an increase in the molecular weight of other proteins. Most of the observed modifications are presumably associated with induction of responses to oxidative damage. Proteins of E. coli and S. warneri are important targets of PDI. Although there is an attempt of cellular response to the PDI-induced damage by overexpression of proteins or synthesis of new proteins, the damage is lethal. Our results show that changes occurring in the protein pattern during photodynamic treatment are different with the two photosensitizers, which help justifying the inactivation kinetics of the two bacteria. SDS-PAGE is a rational approach to assign the type of cellular response to stress that is being induced in the cells.Photochemical and Photobiological Sciences 04/2015; DOI:10.1039/C4PP00194J · 2.94 Impact Factor
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ABSTRACT: The molecular recognition of Human telomeric G-quadruplexes by a novel cationic π-extended NiII-porphyrin (NiII-TImidP4, Chart 1) is studied in aqueous solutions via (chir)optical spectroscopy, Fluorescence Resonance Energy Transfer (FRET) melting assay, and computational molecular modeling. The results are systematically compared to the recognition by a conventional meso-substituted NiII-porphyrin (NiII-TMPyP4, Chart 1), which allows us to pinpoint the differences in binding modes depending on the G-quadruplex topology. Importantly, FRET melting assays show the higher selectivity of NiII-TImidP4 towards human telomeric G4 than that of NiII-TMPyP4.Organic & Biomolecular Chemistry 12/2014; 13(8). DOI:10.1039/C4OB02097A · 3.49 Impact Factor