[Photometric determination of Cu2+ ion using octabromo-tetrakis(4-methylpyridyl)porphine].

Octabromo-tetrakis(4-methylpyridyl)porphine (OBTMPyP), an octabromonated compound with 4 pyrole rings of tetrakis(4-methylpyridyl)porphine, selectively forms a complex with Cu2+ ions at pH 2.0. When 3.6×10(-5) mol/L OBTMPyP was added to the reaction mixture, the calibration curve showed good linearity for Cu2+ ions ranging from 0.01-2.2 µg (addition of 1.0 mL). A good coefficient of variation (Cu2+ ions=1.5 µg (addition of 1.0 mL), n=10, 0.8%) was obtained. The molar absorption coefficient (ε) based on Cu2+ ions was 8.5×10(4) L/mol•cm. This value was 6-fold greater than that determined with a clinical chemical analysis kit using the bathocuproine sulfonic acid method, which is a well-known method for spectrophotometric determination of the Cu2+ ion concentration. A deproteination method was successfully applied in the clinical analysis kit for determination of Cu2+ ion concentrations in control serum I, and the values determined using this method and the bathocuproine sulfonic acid method were almost the same.

[Photometric study on the reaction between 2,3,7,8,12,13,17,18-octabromo- 5,10,15,20-tetrakis-(4-methylpyridyl) porphine and various metal ions].

The chelate forming reaction between 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(4-methylpyridyl)porphine (OBTMPyP) and various metal ions, which belong mainly to 4th period and 7th-12th groups in the periodic table, was examined by the observing the absorption spectra. Because one chemical spicy, H-OBTMPyP, which is one protonated compound at an N atom of pyroll ring among 4 pyroll rings, was observed at pH 9.0, this pH was used to measure the changes of absorption spectra with metal ions. From these changes of absorption spectra of OBTMPyP with metal ions, OBTMPyP were seen to react easily with Cu²âº, Zn²âº, Mn²âº, or Co²âº ion without other additional reagent or heating within 1 min at over 25 °C. On the other hand, OBTMPyP reacted little with Ni²âº, and was not all with Fe³âº (or Fe²âº) reduced by ascorbic acid from Fe³âº) under the same conditions. 5,10,15,20-tetrakis(4-methylpyridyl)porphine (TMPyP) also did not reacted metal ions above these conditions. The λ(max) of each Soret band differed. The stability constants (Ka value) of Cu-, Zn-, Mn- and Co-OBTMPyP was calculated by the change in absorbance of each band, and was 2.6 × 105, 3.6 × 105, 2.7 × 105 and 2.9 × 105 (dm³/mol), respectively. It was revealed that OBTMPyP and metal ions reacted at molar ratio of 1:1, and octabromination of porphine rings improved the reactivity with these ions.

Quercetin diacylglycoside analogues showing dual inhibition of DNA gyrase and topoisomerase IV as novel antibacterial agents.

A structure-guided molecular design approach was used to optimize quercetin diacylglycoside analogues that inhibit bacterial DNA gyrase and topoisomerase IV and show potent antibacterial activity against a wide spectrum of relevant pathogens responsible for hospital- and community-acquired infections. In this paper, such novel 3,7-diacylquercetin, quercetin 6''-acylgalactoside, and quercetin 2'',6''-diacylgalactoside analogues of lead compound 1 were prepared to assess their target specificities and preferences in bacteria. The significant enzymatic inhibition of both Escherichia coli DNA gyrase and Staphylococcus aureus topoIV suggest that these compounds are dual inhibitors. Most of the investigated compounds exhibited pronounced inhibition with MIC values ranging from 0.13 to 128 µg/mL toward the growth of multidrug-resistant Gram-positive methicillin-resistant S. aureus, methicillin sensitive S. aureus, vancomycin-resistant enterococci (VRE), vancomycin intermediate S. aureus, and Streptococcus pneumoniae bacterial strains. Structure-activity relationship studies revealed that the acyl moiety was absolutely essential for activity against Gram-positive organisms. The most active compound 5i was 512-fold more potent than vancomycin and 16-32-fold more potent than 1 against VRE strains. It also has realistic in situ intestinal absorption in rats and showed very low acute toxicity in mice. So far, this compound can be regarded as a leading antibacterial agent.

Design, synthesis, and biological evaluation of a novel series of quercetin diacylglucosides as potent anti-MRSA and anti-VRE agents.

A series of novel quercetin diacylglucosides were designed and first synthesized by Steglich esterification on the basis of MRSA strains inhibiting natural compound A. The in vitro inhibition of different multi-drug resistant bacterial strains and Escherichia coli DNA gyrase B was investigated. In the series, compound 10h was up to 128-fold more potent against vancomycin-resistant enterococci and more effective than A, which represents a promising new candidate as a potent anti-MRSA and anti-VRE agent.

Catalytic activity of silica gels bound manganese(III)-porphyrin on oxidative reaction of adrenaline.

To develop a solid catalysis on oxidative reaction of adrenaline (Ad), supports bound metal-tetrakis(4-carboxyphenyl)porphine (M-TCPP) were investigated. Silica gels bound Mn-TCPP were proved to has a superior activity in the oxidation of Ad and be able to serve as a useful oxidase model for Ad.

Peroxidase-like catalytic activity of Mn- and Fe-tetrakis(4-carboxyphenyl)porphines bound to aminopropyl-glass bead in oxidative reaction of heterocyclic amines.

Fe- or Mn-tetrakis(4-carboxyphenyl)porphine (Fe- and Mn-TCPP) bound to aminopropyl-glass bead (Fe- and Mn-TCPP(g)s) was examined for the peroxidase (POD)-like function in order to develop a solid catalyst which can exhibit POD-like activity without adsorbing heterocyclic amines (HCAs). Mn-TCPP in aqueous solution had only a slight POD-like catalytic activity on HCAs (IQ and MeIQ). As for Fe-TCPP, it was impossible to examine the POD-like activity since it reacted with hydrogen peroxide in a liquid reaction system. However, both Fe- and Mn-TCPP when immobilized on aminopropyl-glass bead via peptide bond (Fe- and Mn-TCPP(g)s), catalyzed the oxidative reaction of mutagenic HCAs with hydrogen peroxide. The catalytic activity of Fe- and Mn-TCPP(g)s was investigated in more detail using as a substrate IQ and MeIQ which were oxidized more rapidly among the tested HCAs. Consequently, the optimal conditions for the oxidative reaction catalyzed by Fe- and Mn-TCPP(g)s were determined. In addition, ESI-mass and absorption spectra of oxidation products of IQ and MeIQ showed that they are dimers. Thus, it was demonstrated that a solid catalyst with POD-like activity can be obtained by immobilizing Fe- and Mn-TCPPs on aminopropyl-glass beads.

Peroxidase-like catalytic activity of anion-exchange resins modified with metal-porphyrins in oxidative reaction of hetrocyclic amines with hydrogen peroxide.

To elucidate the peroxidase (POD)-like catalytic activity of anion-exchange resins modified with metal-tetrakis(sulfophenyl)porphine (M-TSPP(r)s), an oxidative reaction of seven mutagenic heterocyclic amines (HCAs) with hydrogen peroxide, which reaction is catalyzed by horse radish POD, was investigated in the presence of M-TSPP(r)s. Among six M-TSPP(r)s tested, Mn- and Fe-TSPP(r)s were found to have a relatively strong POD-like activity for HCAs, in particular for a typical HCA, 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ). The optimal condition for the POD-like activity was selected using Fe- and Mn-TSPP(r)s. For evaluation of an oxidation product of IQ produced in the presence of Fe-TSPP(r), the absorption, NMR and FAB-mass spectra thereof were compared with those of an oxidation product of IQ produced by horse radish POD or a chemical oxidizing agent, sodium hypochlorite. When Fe-TSPP(r) was present as a catalysts, IQ was converted into the dimmer (hydorazone type) which has no mutagenic activity in umu-test. It was revealed that Fe- and Mn-TSPP(r)s exhibit a POD-like catalytic activity in oxidative reaction of HCAs with hydrogen peroxide.

Effect of carboxylation of N-terminal phenylalanine of (111)in-DTPA (diethylenetriaminepentaacetic acid)-octreotide on accumulation of radioactivity in kidney.

For purpose of reducing renal accumulation of radioactivity of a known radiopharmaceutical agent, i.e., (111)In-DTPA (diethylenetriaminepentaacetic acid)-D-Phe(1)-octreotide, a derivative in which p-carboxy-L-phenylalanine is substituted for D-Phe(1) was synthesized. Biodistribution study of the resultant compound having carboxy-substituted L-Phe(1) revealed that the renal accumulation was significantly lower than that of control compound having unsubstituted L-Phe(1), demonstrating that the presence of negative charge on the N-terminal amino acid of octreotide is effective to reduce the renal accumulation. This effect can be attributed to the reduction of lipophilicity and also the repulsive force arisen from the negative charge of renal brush border membrane.

HPLC retention behavior of poly-aromatic-hydrocarbons on aminopropyl silica gels modified with Cu(II)- and Ni(II)-phthalocyanine derivatives in non-polar eluent.

A comparative study was conducted to elucidate the mechanism underlying the separation of poly-aromatic-hydrocarbons (PAHs) and related compounds thereof on a column packed with silica gels modified with Ni(II)- or Cu(II)-phthalocyanine derivatives (PCS) (Ni- or Cu-PCS(D) column) and commercially available PYE and NPE columns with a non-polar eluent, such as n-hexane. It has been revealed that the dominant interaction responsible to the separation of PAHs on the Cu-PCS(D) and the PYE columns with n-hexane is the pi-pi interaction; however, in the separation of PAHs having 4 rings such as pyrene on the Ni-PCS(D) column, participation of pi-d interaction was indicated. The predominant role of pi-pi interaction in the separation of PAHs of less than three rings on the Ni-PCS(D) column was demonstrated using anthracene. All the columns possessed planar recognition ability and were estimated to be potentially useful in the separation and the analysis of PAHs.

pi-Electron interaction of PAHs with anion-exchange silica gels modified with anionic metal-porphine and -phthalocyanine derivatives as HPLC stationary phase for preparative column in organic solvents.

To develop easy-to-prepare stationary phases for HPLC, we investigated anion-exchange silica gels, Nucleosil 5SB (Nuc), modified with metal-porphines and -phthalocyanines (M-P). The modified silica gels (M-P(N)) were evaluated for the availability as a stationary phase of HPLC for the separation of pi-electron-rich polyaromatic hydrocarbons (PAHs) in polar and non-polar eluents. Separation ability of silica gels modified with Cu-phthalocyanine derivative (Cu-PCS(N)) was comparable to that of the silica gels binding Cu-PCS through sulfonamide bonds; however, the latter requires troublesome procedures for the preparation. The PAHs tested interact with Cu-PCS(N) in non-polar organic eluents through their pi-electrons similarly as in the case of the PYE column((R)), in which interaction with PAHs was reported to be only the pi-pi-electron interaction.

Flow injection analysis of hydrogen peroxide using glass-beads modified with manganese(III)-tetra(4-carboxyphenyl)porphine derivative and its analytical application to the determination of serum glucose.

A flow injection analysis system of hydrogen peroxide was developed. The present system is based on measuring of the absorbance of a quinoid dye formed by the following reaction catalyzed by peroxidase: Phenol + 4-Aminoantipyrine + 2H2O2 --> Peroxidase --> Quinoid dye + 4H2O. A column packed with aminopropyl-glass beads modified with amanganese(III)-tetra(4-carboxyphenyl)porphine derivative (Mn-TCPP(G) column), which has peroxidase-like activity, was used in place of an immobilized peroxidase column in the above reaction. The linear range of the calibration curve was 0.4-80 microg/ml hydrogen peroxide. The relative standard deviation of this system was 2.97% (n = 100, 10 microg/ml hydrogen peroxide 20 microl injection). The Mn-TCPP(G) column has sufficiently stability for the continuous injection of hydrogen peroxide untill 100 times. The advantageous feature of the Mn-TCPP(G) column was a less-electrostatic interaction between the mother glass beads and the anionic chromogen or quinoid dye formed and the stability in terms of the storage, temperature and moisture. The determination of serum glucose was achieved by attaching an immobilized glucose oxidase column to this system without deproteinization.

Flow injection analysis of ascorbic acid using carriers modified with metal-porphine as oxidative solid catalyses.

To investigate one of practical applications of the supports modified with metal-porphines as artificial solid-catalysts, columns into which the supports were packed were supplied to catalytic columns for a flow injection analysis (FIA) system for determination of ascorbic acid (AsA) by the following reactions: AsA+O(2)-->dehydoroAsA+H(2)O(2),H(2)O(2)+chromogen-->2H(2)O+Dye. Among the columns tested, the column containing silica gels modified with Co-tetrakis(carboxyphenyl)porphine catalyzed most rapidly the oxidation reaction of AsA that is accompanied by the formation of hydrogen peroxide. The resulting hydrogen peroxide was determined by FIA system equipped with the column containing glass beads modified with Mn-tetrakis(carboxyphenyl)porphine, which gave a linear calibration curve and large peak-areas of the range corresponding to AsA concentration between 0.2 and 10 micromol/ml. The results indicated that some supports modified with metal-porphine would be applicable to the FIA for AsA as the solid catalyses which function as if the immobilized enzymes.

Photoreaction generating active oxygens of In(3+)-tetrakis(4-methylpyridyl)-porphine in the presence of albumins.

The complex formation of In(3+)-tetrakis(4-N-methylpyridyl)-porphine (In-TMPyP) with albumin was studied by resonance Raman spectroscopy. Albumin coordinated to In(3+) through the -S(-) group(s). The photoreaction was investigated using the visible spectral change and In-TMPyP-thiourea complex was used as a model. It was demonstrated that the complex in a weak basic solution (pH 8.5) is excited by light and the excited complex converts oxygen to superoxide anion, which finally cleavages the porphine ring of In-TMPyP.

Omega-carboxyl variants of 7-ketocholesteryl esters are ligands for beta(2)-glycoprotein I and mediate antibody-dependent uptake of oxidized LDL by macrophages.

beta(2)-Glycoprotein I (beta(2)-GPI) is a major antigen for anticardiolipin antibodies (aCL, Abs) present in patients with antiphospholipid syndrome. We recently reported that beta(2)-GPI specifically binds to oxidized LDL (oxLDL) and that the beta(2)-GPI's major ligand, oxLig-1 is 7-ketocholesteryl-9-carboxynonanoate (Kobayashi, K., E. Matsuura, Q. P. Liu, J. Furukawa, K. Kaihara, J. Inagaki, T. Atsumi, N. Sakairi, T. Yasuda, D. R. Voelker, and T. Koike. 2001. A specific ligand for beta(2)-glycoprotein I mediates autoantibody-dependent uptake of oxidized low density lipoprotein by macrophages. J. Lipid Res. 42: 697-709). In the present study, we demonstrate that omega-carboxylated 7-ketocholesteryl esters are critical for beta(2)-GPI binding. A positive ion mass spectrum of a novel ligand, designated oxLig-2, showed fragmented ions at m/z 383 and 441 in the presence of acetone, which share features of oxLig-1 and 7-ketocholesterol. In the negative ion mode, ions at m/z 627, 625, and 243 were observed. oxLig-2 was most likely 7-ketocholesteryl-12-carboxy (keto) dodecanoate. These ligands were recognized by beta(2)-GPI. Liposome binding to macrophages was significantly increased depending on the ligand's concentration, in the presence of beta(2)-GPI and an anti-beta(2)-GPI Ab. Synthesized variant, 7-ketocholesteryl-13-carboxytridecanoate (13-COOH-7KC), also showed a significant interaction with beta(2)-GPI and a similar binding profile with macrophages. Methylation of the carboxyl function diminished all of the specific ligand interactions with beta(2)-GPI. Thus, omega-carboxyl variants of 7-ketocholesteryl esters can mediate anti-beta(2)-GPI Ab-dependent uptake of oxLDL by macrophages, and autoimmune atherogenesis linked to beta(2)-GPI interaction with oxLDL.