Synthesis, spectroscopy, electrochemistry and DNA interactive studies of meso-tetra(1-naphthyl)porphyrin and its metal complexes

Interaction with CT-DNA and in vitro cytotoxicity of two new copper(II)-based potential drugs derived from octanoic hydrazide ligands

Two copper(II) complexes [Cu(Hpmoh)(NO3)(NCS)] (1) and [Cu(peoh)(N3)]2 (2) were designed and synthesized by reaction of Cu(NO3)2·3H2O with hydrazone Schiff base ligands,abbreviated with Hpmoh and Hpeoh. Hpmoh and Hpeoh were prepared by condensation reaction of octanoic hydrazide with pyridine-2-carboxyaldehyde and 2-acetylpyridine, respectively. Complexes 1 and 2 were characterized using different analytical techniques such as FT-IR, UV-Vis, IR, EPR and single X-ray diffraction (XRD) analyses as well as computational methods (DFT). The XRD of 1 and 2 shows a mononuclear or a dinuclear structure with the copper(II) centre adopting a slightly distorted square pyramidal geometry. In water-containing solution and in DMSO, 1 and 2 undergo a partial transformation with formation of [Cu(Hpmoh)(NO3)(NCS)] (1) and [Cu(Hpmoh)(NO3)(H2O/DMSO)] (1a) in one system and [Cu(peoh)(N3)] (2a) in the other one, as supported by DFT calculations. Docking simulations confirmed that the intercalation is the preferred binding mode with DNA for 1, 1a and 2a, but suggested that the minor groove binding is also possible. A significant fluorescence quenching of the DNA-ethidium bromide conjugate was observed upon the addition of complexes 1 and 2 with a quenching constant around 104 M-1 s-1. Finally, both 1 and 2 were examined for anti-cancer activity using MDA-MB-231 (human breast adenocarcinoma) and A375 (malignant melanoma) cell lines through in vitro MTT assay which suggest comparable cancer cell killing efficacy, with the higher effectiveness of 2 due to the dissociation into two [Cu(peoh)(N3)] units.

Photophysical, photobiological, and mycobacteria photo-inactivation properties of new meso-tetra-cationic platinum(II) metalloderivatives at meta position

In this manuscript, we report the photo-inactivation evaluation of new tetra-cationic porphyrins with peripheral Pt(II) complexes ate meta N-pyridyl positions in the antimicrobial photodynamic therapy (aPDT) of rapidly growing mycobacterial strains (RGM). Four different metalloderivatives were synthetized and applied. aPDT experiments in the strains of Mycobacteroides abscessus subsp. Abscessus (ATCC 19977), Mycolicibacterium fortuitum (ATCC 6841), Mycobacteroides abscessus subsp. Massiliense (ATCC 48898), and Mycolicibacterium smegmatis (ATCC 700084) conducted with adequate concentration of photosensitizers (PS) under white-light conditions at 90 min (irradiance of 50 mW cm-2 and a total light dosage of 270 J cm-2) showed that the Zn(II) derivative is the most effective PS significantly reduced the concentration of viable mycobacteria. The effectiveness of the molecule as PS for PDI studies is also clear with mycobacteria, which is strongly related with the porphyrin peripheral charge and coordination platinum(II) compounds and consequently about the presence of metal center ion. This class of PS may be promising antimycobacterial aPDT agents with potential applications in medical clinical cases and bioremediation.

Main Strategies for the Synthesis of meso-Arylporphyrins

meso-Arylporphyrins as most accessible tetrapyrrole macroheterocycles have always been the focus of attention from researchers concerned with practically useful properties of these compounds. The first syn­theses of meso-arylporphyrins date back to about 90 years ago. Up to now, the yields of these compounds have been improved from 5 to 80%. The present review analyzes different ways and strategies for the synthesis of meso-aryl-substituted porphyrins. The most efficient methods that can be scaled up to an industrial level have been identified.

Interactions of porphyrins with DNA: A review focusing recent advances in chemical modifications on porphyrins as artificial nucleases

The advance of porphyrins as artificial nucleases along the years have developed a class of compounds having potential therapeutic applications. Being an extrovert of chemistry, a variety of chemical modifications have been done on porphyrin macrocycle in order to improve the spectroscopic properties and to adapt as artificial receptors that can recognize molecules. The last twenty years has witnessed broad research in the arena of porphyrin- DNA interactions and their evolution from simple to more complex entities. In this review, we summarize the recent advances in the porphyrin-based structural modifications, with a specific emphasis on various effects of porphyrin on DNA cleavage potency. We particularly detailed the nuclease activity of cationic and anionic porphyrins, porphyrin dimers and conjugates as well as heme proteins till the third generation porphyrins as artificial nucleases.

Halogenated Gallium Corroles:DNA Interaction and Photodynamic Antitumor Activity

A series of halogenated gallium corroles were synthesized and characterized by UV-vis, HRMS, NMR, and FT-IR. The interaction between these gallium corroles and calf thymus DNA had been investigated by spectroscopic methods. These gallium corroles would interact with CT-DNA via an outside binding mode. The photodynamic antitumor activity in vitro of these gallium corroles toward different cell lines had also been tested. 3-Ga displayed low cytotoxicity to normal cells under both light and dark conditions but high phototoxicity to liver cancer cells HepG2. The vitro experiment results showed that 3-Ga could be efficiently absorbed by tumor cells. After light illumination, it may induce reactive oxygen species (ROS) and cause destruction of the mitochondrial membrane potential, which may finally trigger tumor cell apoptosis. Flow cytometry results showed that HepG2 cells were mainly distributed in the sub-G0 phase, which corresponds to cells with highly fragmented DNA or dead cells generally. This suggests that 3-Ga could lead to tumor cell apoptosis after light illumination.

Fluorescent pyrene moiety in fluorinated C6F5-corroles increases the interaction with HSA and CT-DNA

Two fluorinated meso-C6F5-corroles (5,15-bis(pentafluorophenyl)-10-(phenyl)corrole and 5,15-bis(pentafluorophenyl)-10-(1-pyrenyl)corrole) were biologically evaluated in terms of binding affinity to human serum albumin (HSA) and calf-thymus DNA (CT-DNA) via multiple spectroscopic techniques under physiological conditions combined with molecular docking calculations. The HSA:corrole interaction is spontaneous and moderate via static binding, disturbing both secondary and tertiary albumin structures at high fluorinated corrole concentrations. The competitive binding studies indicated positive cooperativity or allosteric activation, while molecular docking calculations suggested that both fluorinated corroles bind preferentially inside subdomains IIA and IB (sites I and III, respectively). The experimental CT-DNA binding assays indicated that fluorinated corroles interact spontaneously by non-classical modes in the minor groove of the CT-DNA strands via static fluorescence quenching mechanism. Molecular docking results also showed the minor groove as the main binding site for CT-DNA. Overall, the pyrene moiety increased the interaction with HSA and CT-DNA, which is probably due to the planarity and volume that favors the pyrene unit to be buried inside the biomacromolecule pockets.

Modified pyrazole platinum(II) complex can circumvent albumin and glutathione: Synthesis, structure and cytotoxic activity

The synthesis and structural characterization of novel platinum complexes ([Pt^II(Pz)₂Cl₂] - C1, C2 and C3) featuring diphenyl-pyrazole derived ligands: para-fluorophenyl and para-substituted phenyl (CH₃, F and Cl for L1, L2 and L3, respectively) were reported and it was also evaluated their potential antitumor activity. The elemental, molar conductivity and thermogravimetric analysis combined with FTIR, UV-vis, NMR and mass spectrometry are in agreement with the chemical structure indicated by single-crystal X-ray diffraction. The antiproliferative activities were assessed against tumor (B16F10 and 4T1) and non-tumor (BHK21) cell lines, and the cytotoxicity of the compounds was strongly increased after metal complexation displaying promising activity. It was also assessed the ability of extracellular bovine serum albumin (BSA) and glutathione (GSH) to decrease the cytotoxicity of the complexes against B16F10. It was highlighted that only the C3 activity was not disturbed in those conditions, being confirmed by flow cytometry using Anexin-V/PI to evaluate interferences in the apoptosis process, even it was not predicted by molecular docking simulations. The interaction of the synthesized compounds with calf-thymus DNA (ctDNA) and bovine serum albumin (BSA) was also investigated through spectrophotometric assays and molecular docking simulations, indicating that C1 and C2 presented better interaction with the biomacromolecules than the corresponding ligands. In addition, agarose gel electrophoresis with plasmid DNA revealed that C1-C3 are capable of interaction with DNA and modify its electrophoretic mobility.

Meso-tetra(4-carboxyphenyl)porphine-Enhanced DNA Methylation Sensing Interface on a Light-Addressable Potentiometric Sensor

DNA methylation (DNAm) sensors are an emerging branch in the discipline of sensors. It is believed to be able to promote the next generation of epigenetics-based diagnostic technology. Differing from the traditional biochemical sensors that aimed at individual molecules, the challenge in DNAm sensors is how to determine the amount of 5-methylcytosine (5mC) in a continuous nucleotide sequence. Here, we report a comparative study about meso-tetra(4-carboxyphenyl)porphine (TCPP)-based DNAm sensing interfaces on a light-addressable potentiometric sensor (LAPS), depending on TCPP's postures that are flat in the π-conjugated TCPP layer on reduced-graphene-oxide-decorated LAPS (#1) and stand-up in the covalently anchored TCPP on glutaraldehyde (GA)-treated LAPS (#2), along with the blank one (only GA-treated LAPS, #3). These DNAm sensing interfaces are also distinct from the traditional biosensing interface on LAPS, that is: it is not functionalized by the sensing indicator (5mC antibody, in this case) but by the target nucleotide sequence. The surface characterization techniques such as Raman spectra, scanning electron microscopy, and X-ray photoelectron spectroscopy are conducted to prove the decorations, as well as the anchored nucleotides. It is found that, though all of them can detect as low as one 5mC in the target sequence, the enhanced DNAm sensitivity is obtained by #2, which is evidenced by the higher output-voltage changing ratio for the 5mC site of #2 than those of #1 and #3. Furthermore, the underlying causes for the improved sensitivity in #2 are proposed, according to the conformational and electronic properties of TCPP molecules. Conclusively, TCPP's synergetic function, including the molecular configuration and the activate (carboxyl) groups on its peripheral substituents, to improve the DNAm sensing interface on LAPS is investigated and demonstrated. This can shed light on a new approach for DNA methylation detection, with the merits of low cost, independence on bisulfite conversion, and polymerase chain reaction.

DNA interaction and photodynamic antitumor activity of transition metal mono-hydroxyl corrole

A series of iron(III), manganese(III) and copper(III) mono-hydroxyl corrole complexes had been prepared and well characterized by UV-vis, ¹H NMR, ¹⁹F NMR and HR-MS. These metallocorroles may bind to CT-DNA through external binding mode. Metallocorrole Fe-2c exhibited significant phototoxicity and low toxicity toward A549 tumor cells. While manganese (III) and copper (III) corroles showed hypotoxicity to A549, MCF-7 and HepG-2 tumor cells, whether under dark or illumination conditions. All tested metallocorroles exhibited non-toxicity to human normal cells (GES-1) with or without irradiation at 625 nm. Cell cycle analysis indicated that metallocorrole Fe-2c arrested the cell cycle at G2/M phase and increased the Sub-G1 phase in A549 cell lines. It was mainly localized at mitochondria and could significantly reduce mitochondrial membrane potential after photodynamic treatment, which would further induce tumor cell apoptosis.

Voltage Stimulated Anion Binding of Metalloporphyrin-induced Crystalline 2D Nanoflakes

Voltage-stimulated redox-active materials have received significant attention in the field of organic electronics and sensor technology. Such stimuli-responsive materials trigger the formation of crystalline nanostructures and facilitate the design of efficient smart devices hitherto unknown. Herein, we report that free-base and metallo-tetratolylporphyrin-linked ferrocene derivatives (H₂ TTP-Fc and ZnTTP-Fc) undergo distinct proton/anion binding mechanism in CHCl₃ during bulk electrolysis at applied voltage of 1.4 V to give [H₄ TTP-Fc]⁺ Cl^- and H⁺ [(Cl)ZnTTP-Fc]^- followed by nanospheres and crystalline 2D nanoflakes formation, confirmed by SEM and TEM images, by methanol vapor diffusion (MVD) approach. Moreover, X-ray diffraction analysis suggest that protonated H₂ TTP-Fc aggregates exhibit amorphous nature, whereas H⁺ [(Cl)ZnTTP-Fc]^- depict crystalline nature from layer-by-layer arrangement of nanoflakes assisted by π-π stacking and ion-dipole interactions.