Coumarin-3-Carboxylic Acid

Radiation Chemical Yield of Hydroxyl Radicals for Accelerator-based Boron Neutron Capture Therapy: Dose Assessment of (10)B(n,alpha)(7)Li Reaction Using Coumarin-3-Carboxilic Solution.[Pubmed:30896280]

Radiat Res. 2019 Mar 21.

Evaluation of the characteristics of accelerator-based thermal neutron fields is recognized as an important issue when discussing the effectiveness of boron neutron capture therapy (BNCT). In this study, we propose that the radiation chemical yield (G value) of hydroxyl radicals (GOH*) can be considered a universal parameter for the description of the accelerator-based thermal neutron field. The GOH* of the (10)B(n,alpha)(7)Li reaction was quantitatively evaluated using an aqueous Coumarin-3-Carboxylic Acid (3CCA) solution, and was discriminated from that of contaminations (i.e., gamma rays and fast neutrons). The GOH* of the (10)B(n,alpha)(7)Li reaction was 0.107 +/- 0.004 OH(*)/100 eV, which is almost equivalent to that exposed to alpha particles with an energy of 6.0 MeV. Since the GOH* of gamma rays from a (60)Co source is 2.03 +/- 0.05 OH(*)/100 eV, this lower value suggests that indirect action by the (10)B(n,alpha)(7)Li reaction is not dominant in BNCT. However, our results indicate that one can assess the (60)Co equivalent dose of the (10)B(n,alpha)(7)Li reaction in water from the GOH* derived using aqueous 3CCA solution in the accelerator-based thermal neutron field.

Tagging synthetic polymers with coumarin group for study nucleic acid interaction with gene delivery agents.[Pubmed:30766801]

MethodsX. 2019 Jan 24;6:212-218.

Polymeric amines and complex amine containing system are actively studied and applied as gene delivery agents in gene therapy and genetic engineering. Optimizing polymer - nucleic acid ratio is the key stage in elaboration of procedures in this area. Application of fluorescent tagged oligonucleotides is widespread approach which allows to visualize nucleic acid in gel electrophoresis experiments and to find conditions of the full binding of the nucleic acid. We suggest to use succinimidyl ester of 7-(diethylamino)Coumarin-3-Carboxylic Acid as an agent for fluorescent labeling of polymeric amines and to use the tagged polymers in optimizing polymer - nucleic acid ratio. This approach allows to see unbound polymer and to study various nucleic acids in interaction with the same polymer. *Labeling of gene delivery agents with fluorescence groups increases efficiency of optimization of gene delivery compositions.*Polymeric amines tagged with succinimidyl ester of 7-(diethylamino)Coumarin-3-Carboxylic Acid are suitable for study polymer - nucleic acid interaction with gel electrophoresis.

Radio-Fluorogenic Gel Dosimetry with Coumarin.[Pubmed:29996496]

Bioengineering (Basel). 2018 Jul 10;5(3). pii: bioengineering5030053.

Gel dosimeters are attractive detectors for radiation therapy, with properties similar to biological tissue and the potential to visualize volumetric dose distributions. Radio-fluorogenesis is the yield of fluorescent chemical products in response to energy deposition from ionizing radiation. This report shares the development of a novel radio-fluorogenic gel (RFG) dosimeter, gelatin infused with coumarin-3-carboxlyic acid (C3CA), for the quantification of imparted energy. Aqueous solutions exposed to ionizing radiation result in the production of hydroxyl free radicals through water radiolysis. Interactions between hydroxyl free radicals and Coumarin-3-Carboxylic Acid produce a fluorescent product. 7-hydroxy-Coumarin-3-Carboxylic Acid has a blue (445 nm) emission following ultra-violet (UV) to near UV (365(-)405 nm) excitation. Effects of C3CA concentration and pH buffers were investigated. The response of the RFG was explored with respect to strength, type, and exposure rate of high-energy radiation. Results show a linear dose response relationship independent of energy and type, with a dose-rate dependency. This report demonstrates increased photo-yield with high pH and the utility of gelatin-RFG for phantom studies of radiation dosimetry.

Comparisons of the spectroscopic and microbiological activities among coumarin-3-carboxylate, o-phenanthroline and zinc(II) complexes.[Pubmed:29547823]

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Jun 5;198:212-221.

Coumarins (2H-chromen-2-one) are oxygen-containing heterocyclic compounds that belong to the benzopyranones family. In this work we have synthesized different coordination complexes with Coumarin-3-Carboxylic Acid (HCCA), o-phenanthroline (phen) and zinc(II). In the reported [Zn(CCA)2(H2O)2] complex, coumarin-3-carboxylate (CCA) is acting as a bidentate ligand while in the two prepared complexes, [Zn(phen)3]CCA(NO3) (obtained as a single crystal) and [Zn(CCA)2phen].4H2O, CCA is acting as a counterion of the complex cation [Zn(phen)3](+2) or coordinated to the metal center along with phen, respectively. These compounds were characterized on the basis of elemental analysis and thermogravimetry. NMR, FTIR and Raman spectroscopies of the compounds and the CCA potassium salt (KCCA) allow to determine several similarities and differences among them. Finally, their behavior against alkaline phosphatase enzyme and their antimicrobial activities were also measured.

At the crossroad of photochemistry and radiation chemistry: formation of hydroxyl radicals in diluted aqueous solutions exposed to ultraviolet radiation.[Pubmed:29075688]

Phys Chem Chem Phys. 2017 Nov 8;19(43):29402-29408.

Formation yields of OH radicals were precisely determined in aqueous solutions of Coumarin-3-Carboxylic Acid and ferrous sulfate (i.e., Fricke dosimeter) exposed to 253.7 nm radiation delivered from a continuous source. Quantum yield of OH radicals was determined as approximately 0.08, i.e., roughly one out of twelve photons, efficiently absorbed in UV-illuminated solutions, produced one OH radical. Energetically, a water molecule should undergo a correlated action of at least two 4.9 eV photons delivering enough energy for direct H-OH dissociation (5.0-5.4 eV). We suggest a mechanism based on an interaction of two water molecules, both in long-living triplet states. An intermolecular transfer of excitation energy provided a sufficient amount of energy for the dissociation of one water molecule into OH and H radicals. In an aqueous solution of phospholipids, quantum yields of hydroperoxides formed under these irradiation conditions decreased with total effectively absorbed energy (i.e. a dose), similar to the radiation chemical yields obtained during an exposure to ionizing radiation, such as gamma rays from radionuclide sources. Under 253.7 nm irradiation, one OH radical causes a peroxidation of 34 phospholipid molecules. This implicates chain mechanism of the reaction.

Enhanced luminescence of delaminated layered europium hydroxide (LEuH) composites with sensitizer anions of coumarin-3-carboxylic acid.[Pubmed:28914950]

Dalton Trans. 2017 Sep 26;46(37):12724-12731.

The organic compound of Coumarin-3-Carboxylic Acid (CCA), deprotonated beforehand by NaOH, and the 1-octane sulfonic acid anion (OS) were co-intercalated into the gallery of the layered europium hydroxide (LEuH) via an ion exchange method. Different molar ratios of CCA/OS and NaOH/CCA gave rise to the composites of CCA1-xOSx-LEuH (x = 0.8-1.0) showing different emission intensities. In formamide (FM), all composites were delaminated and the formed colloidal suspensions exhibited enhanced red luminescence of Eu(3+) in comparison with the OS-LEuH without CCA. Also, the red emissions of the composites were different from the violet emission (421 nm) of free CCA(-) and blue emission (471 nm) of CCA(2-) anions in different deprotonation states. The energy levels of CCA and Eu(3+) were analyzed to explain the sensitization effect for Eu(3+) luminescence. The fluorescence lifetimes of CCA0.2OS0.8-LEuH-1 : 1, CCA0.02OS0.98-LEuH-1 : 1, CCA0.2OS0.8-LEuH-1 : 2, and CCA0.02OS0.98-LEuH-1 : 2 were determined to be 0.705, 0.704, 0.699 and 0.638 ms, respectively, indicating significantly longer lifetimes. The PL quantum yields of approximately 10% demonstrate the excellent luminescence properties of the as-prepared CCA1-xOSx-LEuH composites. This is the first report on the sensitized luminescence properties of layer Eu(3+) ions in LRH composites in the delaminated state. The intriguing red luminescence of delaminated LEuH composites offers a promising approach to achieve efficient luminescent film materials.

1,1'-Carbonyldiimidazole (CDI) Mediated Facile Synthesis, Structural Characterization, Antimicrobial Activity, and in-silico Studies of Coumarin- 3-carboxamide Derivatives.[Pubmed:28641525]

Med Chem. 2018;14(1):86-101.

BACKGROUND: Despite the availability of a variety of antibacterial agents, re-emergence of pathogenic bacteria is still a serious medical concern. So, identification of new, safer, and selective antibacterial agents is the key interest in the medicinal chemistry research. METHOD: To explore the antimicrobial activity of coumarin-3-carboxamides for a range of bacterial and fungal strains, twenty eight derivatives were synthesized by the reaction of Coumarin-3-Carboxylic Acid with a variety of aniline derivatives in the presence of 1,1'-carbonyldiimidazole (CDI). All compounds were structurally characterized by different spectroscopic techniques EI-MS, HREI-MS, 1H-NMR, 13C-NMR, and evaluated for antimicrobial activities (antibacterial and antifungal). RESULTS: A number of compounds showed good to weak antibacterial activity against various strains of Gram-positive and Gram-negative bacteria. Amongst them, compound 28 displayed noticeable inhibition against five strains of Gram-positive (Bacillus subtilis, Corynebacterium xerosis, Staphylococcus aureus, Streptococcus faecalis, and MRSA) and four strains of Gram-negative bacteria (Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter aerogene, and Shigella dysenteria). However, none of the compounds showed antifungal activity against tested fungi. MIC values were determined for most of the active compounds 2, 15, and 28 against particular bacterial cultures. In silico studies were performed on the most active compound 28 in order to specify and verify the target for antibacterial activity of synthetic coumarin-3-carboxamide derivatives. The cytotoxicity of these compounds on mammalian cells is unknown yet but we are planning to carry out research on the cytotoxic aspect of these compounds in future. CONCLUSION: The newly identified compounds may serve as lead molecules for the future research regarding the identification of new antibacterial agents.

The Coumarin-Dimer Spring-The Struggle between Charge Transfer and Steric Interactions.[Pubmed:28500858]

Chemistry. 2017 Jul 6;23(38):9174-9184.

The synthesis of a weakly coupled, strongly polarized coumarin dimer has been achieved for the first time. The three-step strategy comprises the Skattebol formylation followed by the Knoevenagel reaction and the formation of a tertiary amide by using a peptide-type procedure. The molecule consists of two different coumarin moieties: One is a classical donor-acceptor system and the second one possesses a weaker amide donor at the 7-position. The polarized coumarin dimer can form an electronically conjugated structure possessing an electric dipole larger than that of 7-(dimethylamino)Coumarin-3-Carboxylic Acid. The limited flexibility of the inter-coumarin connection results in stable conformers of different electric dipole moments and complex photophysics. In the solid state, this compound has a strongly bent conformation with the two coumarin units forming an angle of around 74 degrees . In solution, two conformers are in equilibrium. The existence of the molecule as two conformers in the ground state has been confirmed by optical studies, and further corroborated by molecular calculations. The fluorescence spectra possess a unique feature: A charge-transfer band (ca. 550 nm) is visible only in nonpolar or weakly polar solvents. Optical spectroscopy studies coupled with molecular calculations allowed us to rationalize this phenomenon: The large amplitude of intramolecular motions is responsible for the conformational isomerization as well as producing a conical intersection between the potential energy surfaces of the excited singlet state and the ground state, which opens an internal conversion channel that effectively competes with the fluorescence of the conformers.

Visualization of Fluoride Ions In Vivo Using a Gadolinium(III)-Coumarin Complex-Based Fluorescence/MRI Dual-Modal Probe.[Pubmed:27999298]

Sensors (Basel). 2016 Dec 16;16(12). pii: s16122165.

A new Gadolinium(III)-coumarin complex, DO3A-Gd-CA, was designed and prepared as a dual-modal probe for simultaneous fluorescence and relaxivity responses to fluoride ions (F(-)) in aqueous media and mice. DO3A-Gd-CA was designed by using Gd(III) center as an MRI signal output unit and fluoride binding site, and the 4-(diethylamino)-Coumarin-3-Carboxylic Acid (CA) as a fluorescence reporter. Upon the addition of fluoride ions to the solution of DO3A-Gd-CA, the liberation of the coordinated CA ligand led to a 5.7-fold fluorescence enhancement and a 75% increase in the longitudinal relaxivity (r(1)). The fluorescent detection limit for fluoride ions was determined to be 8 muM based on a 3sigma/slope. The desirable features of the proposed DO3A-Gd-CA, such as high sensitivity and specificity, reliability at physiological pH and low cytotoxicity enable its application in visualization of fluoride ion in mice. The successful in vivo imaging indicates that DO3A-Gd-CA could be potentially used in biomedical diagnosis fields.

Fluorescence Quenching of Two Coumarin-3-carboxylic Acids by Trivalent Lanthanide Ions.[Pubmed:27924439]

J Fluoresc. 2017 Mar;27(2):619-628.

The effects of various trivalent lanthanide ions (acetates of Ce(3+), Er(3+), Eu(3+), Nd(3+)) on the electronic absorption and fluorescence spectra of un-substituted Coumarin-3-Carboxylic Acid (CCA) and 7-N,N-diethylamino-Coumarin-3-Carboxylic Acid (DECCA) have been investigated in dimethylsulfoxide (DMSO) at room temperature. Depending on the lanthanide ion nature and concentration, significant spectral changes of absorption bands occurred for both coumarin derivatives. These spectral changes were attributed to the formation of ground-state complexes between the coumarin carboxylate derivatives and lanthanide ions. The fluorescence quenching of CCA and DECCA upon increasing the lanthanide ion concentration was studied. Different quantitative treatments, including the Stern-Volmer equation, the Perrin equation and a polynomial equation, were applied and compared in order to determine the nature of the quenching mechanisms for both coumarin derivatives. The results suggested the contribution of both dynamic and static quenching. Significant differences of CCA and DECCA fluorescence quenching efficiency were also observed, depending on the lanthanide ion. DECCA fluorescence lifetime measurements, performed in the absence and in the presence of Ln(3+), confirmed a contribution of static quenching.

A highly Selective Fluorescent Chemosensor for Zn(2+) Based on the Rhodamine Derivative Incorporating Coumarin Group.[Pubmed:27900512]

J Fluoresc. 2017 Mar;27(2):629-633.

A coumarin-appended rhodamine derivative was prepared by reacting rhodamine hydrazide and Coumarin-3-Carboxylic Acid, which fluorescence sensing behavior toward Zn(2+) against other metal ions was investigated in CH3CN. Significantly, the rodamine-coumarin derivative exhibited highly selective and sensitive recognition toward Zn(2+) with a limit of detection (LOD) down to 10(-9) M. Upon addition of Zn(2+), remarkable fluorescent intensities enhanced and also clear color changed from colorless to pink. The Job's plot indicated the formation of 1:1 complex between the rhodamine-coumarin derivative and Zn(2+). The presence of common coexisting alkali, alkaline earth, and transition metal ions showed small or no interference with the detection of Zn(2+). The conjugate dye could be used for "naked-eye" detection of Zn(2+).

Preparation and characterization of photoactive antimicrobial graphitic carbon nitride (g-C3N4) films.[Pubmed:27672437]

RSC Adv. 2016;6(48):42240-42248.

Photoactive films derived from nanostructured samples of metal-free, intermediate band gap semiconductor graphitic carbon nitride (ns-g-C3N4) have been synthesized and characterized for their particle properties and antimicrobial activity. Physical characterization reveals that these materials are composed of discrete nanoparticles whose dimensions range from 200 nm to 700 nm. Investigation of the photochemical reactivity of ns-g-C3N4 using Coumarin-3-Carboxylic Acid (3-CCA) indicates that this material produces reactive oxygen species (ROS) under visible radiation. When irradiated with 0.31J visible light, ns-g-C3N4-based materials reduced the viability of both gram-negative Escherichia coli O157:H7 and gram-positive Staphylococcus aureus by approximately 50%. Nearly complete inactivation of both strains of microorganisms was achieved upon administration of a 0.62J dose of visible radiation. Importantly, no biocidal activity was observed for non-irradiated samples, indicating that the g-C3N4-derived films are not inherently toxic in the absence of visible light. The results of this study suggest that materials and, by extention, films and coatings derived from g-C3N4 may present a novel route for controlling pathogenic microorganisms on surfaces in the environment, and could be useful in reducing incidents of hospital-acquired infections.

Tripeptide GGH as the Inhibitor of Copper-Amyloid-beta-Mediated Redox Reaction and Toxicity.[Pubmed:27433833]

ACS Chem Neurosci. 2016 Sep 21;7(9):1255-63.

The Abeta complexes of some redox-active species, such as Cu, cause oxidative stress and induce severe toxicity by generating reactive oxygen species (ROS). Thus, Cu chelation therapy should be considered as a valuable strategy for the treatment of Alzheimer's disease (AD). However, more attention should be paid to the specific chelating ability of these chelating agents. Herein, a tripeptide GGH was used to selectively chelate the Cu(2+) in Abeta-Cu complex in the presence of other metal ions (e.g., K(+), Ca(2+), Ni(2+), Mg(2+), and Zn(2+)) as shown by isothermal titration calorimetry results. GGH decreased the level of HO(*) radicals by preventing the formation of intermediate Cu(I) ion. Thus, the Cu species completely lost its catalytic activity at a superequimolar GGH/Cu(II) ratio (4:1) as observed by UV-visible spectroscopy, Coumarin-3-Carboxylic Acid fluorescence, and BCA assay. Moreover, (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay indicates that GGH increased PC-12 cell viability from 36% to 63%, and neurotoxicity partly triggered by ROS decreased. These results indicate potential development of peptide chelation therapy for AD treatment.

Use and Evaluation of Newly Synthesized Fluorescence Probes to Detect Generated OH* Radicals in Fibroblast Cells.[Pubmed:26983614]

J Fluoresc. 2016 May;26(3):919-24.

Reactive oxygen species (ROS) are pro-oxidant molecules synthesized in body with various functions and are essential for life. Increasing in reactive oxygen species or decreasing in antioxidants level cause oxidative stress which is very harmful. OH* radical is one of ROS's, with tendency to bind to lipids, DNA and proteins which cause irreversible damage in cells. The most devastating consequences related to excess OH* radicals occur via direct binding to nucleic acids and proteins. Quantification of this high reactive radical with short life time is difficult. Electron Spin Resonance, Fluorescence, and Luminescence Spectroscopy are commonly used to determine the level of ROS. Fluorescence Probes have higher specificity and sensitivity with their excellent sensors to detect ROS's compare to the other methods. Also, there are different probes specifically designed for each radical. The purpose of this study was to identify the probe better suiting for detection of OH* radical levels. The two most recommended fluorescence probes, 2-[6-(4 V-Hydroxy) phenoxy-3H-xanthen-3-on-9-yl]benzoic acid (HPF) and Coumarin-3-Carboxylic Acid (3-CCA) to determine OH* radical levels were compared. Following the formation of OH* radical with Fenton reaction, HPF and 3-CCA probes were added to cells and spectrofluorometric measurements were performed in their respective wavelengths. The mean amplitude of fluorescence for HPF was 32.72 +/- 2.37 F.I (n = 40) and for 3-CCA was 52.11 +/- 0.5 F.I (n = 40). This difference was statistically significant. 3-CCA also demonstrated more stable measurements at different days compered to HPF.

Coumarin-3-carboxylic acid (2- Oxochromene-3-carboxylic acid) is an important initial compound for the synthesis of coumarins which are well known natural products for their diverse biological activities. Lanthanide complexes of Coumarin-3-carboxylic acid exhibit antiproliferative activity towards K-562 cell line.

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