92739-63-4Relevant academic research and scientific papers
Insight into ultrasound-mediated reactive oxygen species generation by various metal-porphyrin complexes
Giuntini, Francesca,Foglietta, Federica,Marucco, Arianna M.,Troia, Adriano,Dezhkunov, Nikolai V.,Pozzoli, Alessandro,Durando, Gianni,Fenoglio, Ivana,Serpe, Loredana,Canaparo, Roberto
, p. 190 - 201 (2018)
Ultrasound is used to trigger the cytotoxicity of chemical compounds, known as sonosensitisers, in an approach called sonodynamic therapy (SDT), which is under investigation herein. The generation of reactive oxygen species (ROS) has been proposed as the main biological occurrence that leads to the cytotoxic effects, which are achieved via the synergistic action of two components: the energy-absorbing sonosensitiser and ultrasound (US), which are both harmless per se. Despite some promising results, a lack of investigation into the mechanisms behind US sonosensitiser-mediated ROS generation has prevented SDT from reaching its full potential. The aim of this work is to investigate the US-responsiveness of a variety of metal-porphyrin complexes, free-base porphyrin and Fe(III), Zn(II) and Pd(II) porphyrin, by analyzing their ROS generation under US exposure and related bio-effects. All experiments were also carried out under light exposure and the results were used as references. Our results show that porphyrin ultrasound-responsiveness depends on the metal ion present, with Zn(II) and Pd(II) porphyrin being the most efficient in generating singlet oxygen and hydroxyl radicals. ROS production efficiency is lower after ultrasound exposure than after light exposure, because of the various physico-chemical mechanisms involved in sensitiser activation. US and porphyrin-mediated ROS generation is oxygen-dependent and the activation of porphyrin by US appears to be more compatible with sonoluminescence-based photo-activation rather than a radical path process that occurs via the homolytic bond rupture of water. Notably, the cytotoxicity results reported herein, which are mirrored by ex-cellulo data, confirm that the type of ROS generation achieved by the US activation of intracellular porphyrins is pivotal to the effectiveness of cancer cell killing.
New porphyrin-nucleobase hybrid compounds and their interaction with nucleosides and nucleic acids
Malinovski, Vladimir,Tumir, Lydia,Piantanida, Ivo,Zinic, Mladen,Schneider, Hans-Joerg
, p. 3785 - 3795 (2002)
Four new porphyrin derivatives are described: one (1) with a methoxyphenyl group and three pyridinium units (for comparison only), and three others with either adenine (2, 3) or thymine (4) bases. The synthetic strategies vary from known literature procedures in that the methylation of pyridinium subunits takes place before the formation of the hybrid molecule, beginning with simultaneous condensation of pyridinealdehyde and 3-(propionyloxy)benzaldehyde, with subsequent chromatography under improved conditions. The thymine derivative 4 is obtained from trimethylated tetrapyridylporphyrin T4PyP by treatment with a suitable thyminealkyl bromide. Dilution experiments in water show the absence of intermolecular porphyrin associations under the experimental conditions used. UV and NMR spectroscopic data indicate strong intramolecular self-stacking between the porphyrin moiety and the covalently attached nucleobases. This results in smaller affinities of porphyrin-nucleobase conjugates towards added nucleosides than observed with the reference compounds tris- or tetrakis-pyridinium porphyrin (1 and TMPyP, respectively). Compounds 2-4 displayed no significant discrimination between A and T based on complementarity of nucleobases, which is explained by the strong competition from bulk water with Watson-Crick hydrogen bonds. Interactions of ligands 1-4 with ct DNA and ss-RNA polynucleotides were studied by fluorimetric and UV/Vis titration. In most cases the fluorescence of 1-4 was first quenched by addition of polynucleotide at porphyrin/ polynucleotide ratios (r) close to saturation of intercalation binding sites, and then enhanced at ratios r 0.1 were attributed to intermolecular association of porphyrins along the polynucleotide groove, while the changes observed at large excess of intercalation binding sites (r 0.1) indicate intercalation of porphyrin into the polynucleotide. Scatchard analyses at r 0.1 are in most cases in line with the formation of only 1:1 complexes. With poly U the non-complementary compounds 1 and 4 showed only increased fluorescence, while the complementary compounds 2 and 3 showed decreases as well as increases. Addition of poly U to 2 and 3 induced strong bathochromic shifts of the Soret bands, characteristic of intercalation. Although no affinity difference between complementary and non-complementary complexes of 2-4 and ss-polynucleotides was observed, significant differences in emission changes in poly U titrations suggest specific interactions of the adenine conjugates 2 and 3. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
CATALYTIC CARBONYLATION CATALYSTS AND METHODS
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Page/Page column 99, (2012/12/13)
In one aspect, the present invention provides catalysts for the carbonylation of heterocycles. The inventive catalysts feature metal-ligand complexes having cationic functional groups tethered to the ligand, wherein the tethered cationic groups are associated with anionic metal carbonyl species. The invention also provides methods of using the inventive catalysts to affect the ring opening carbonylation of epoxides.
Cyclodextrin carriers of positively charged porphyrin sensitizers
Mosinger, Jii,Slavtinska, Lenka,Lang, Kamil,Coufal, Pavel,Kubat, Pavel
experimental part, p. 3797 - 3804 (2009/10/23)
The cationic sensitizer 5,10,15,20-tetrakis(N-methylpyridinium-4-yl) porphyrin (TMPyP) forms supramolecular complexes with native, per-methylated, sulfonated and dimethyl-sulfonated cyclodextrins (CDs). Binding interactions were proved by NMR, mass spectra, capillary zone electrophoresis, UV-Vis and fluorescence spectroscopy. The 2D-NMR experiments on native CDs indicate that the interaction of TMPyP with the external CD surface is the dominant binding mode. The high binding affinity of TMPyP towards sulfonated CDs is due to electrostatic interactions. Binding is accompanied by an increase of the TMPyP basicity. Whereas βCD does not affect the lifetime of the TMPyP triplet states, binding with sulfonated CDs causes the protonation of the TMPyP triplet states even in neutral solution. The diprotonated anionic sensitizer 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPSH22+) forms host-guest complexes with native βCD and γCD, similarly as in its non-protonated state. The positive charge of pyrrole nitrogen atoms does not significantly influence the mode of the interaction. In contrast to TMPyP, the lifetimes of the triplet states of bound TPPSH22+ to native CDs increase.
Luminescence Properties of Water-Soluble Cationic Platinum(II) and Palladium(II) Porphyrins
Blinova, I. A.,Vasil'ev, V. V.
, p. 995 - 999 (2007/10/02)
The luminescence properties Pt(II) and PD(II) complexes with meso-tetrakis(N-methylpyridyl)porphyrin (H2TMPyP4+) are studied.It is shown that metalloporphyrins in sodium dodecylsulfate micelles are monomeric.In dilute aqueous solutions, no monomer-dimer equilibrium is observed, but the addition of chloride ions gives rise to metalloporphyrin aggregation.The rate constants calculated for radiative (krad) and nonradiative (knon) deactivation of the electronically excited triplet state increase in passing from PdTMPyP4+ to PtTMPyP4+, which is explained by the heavy-atom effect.It is also shown that, during dimerization and aggregation, the value of the krad constant remains constant (for PtTMPyP4+ and PdTMPyP4+, its values are 1325 and 60 s-1, respectively), whereas the value of the knon constant increases.
