Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Hydroxyquinolines”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1983

[Differences in the action of antimycin and 2-nonyl-4-hydroxyquinoline N-oxide on oxidation-reduction of mitochondrial cytochromes b].

The differences in the effects of two similar electron transfer inhibitors, antimycin and 2-nonyl-4-hydroxyquinoline N-oxide (HOQNO) on the reactions of cytochromes b are described. In the cyanide-inhibited submitochondrial particles of bovine heart, HOQNO strongly stimulates cytochrome b reduction by ascorbate in the presence of redox mediators, e. g. N,N,N',N'-tetramethylparaphenylene diamine, 2,6-dichlorophenolindophenol, diaminodurol and phenazine methosulfate; this effect can be reversed by antimycin. Addition of both inhibitors to the submitochondrial particles aerobically equilibrated with succinate/fumarate redox buffer at E = +54 mV in the presence of cyanide results in a similar reduction of cytochromes b, which in the case of antimycin is readily reversed by phenazine methosulfate but is resistant to this redox mediator in the presence of HOQNO. The latter causes additional reduction of cytochrome b562 in the argone atmosphere, the effect being reversed by antimycin. In the presence of HOQNO the anaerobic redox titration curve of cytochrome b562 is shifted towards a high potential region by 20-30 mV. An additional reduction of cytochromes b induced by HOQNO can be due to superposition of two effects, i. e. extra-reduction of cytochromes b566 and b562 requiring O2 and a true positive shift of E0 of cytochrome b562.

Animals↗
PubMed1982

Human platelets labeled with In-111 8-hydroxyquinoline: kinetics, distribution, and estimates of radiation dose.

Platelets from nine normal male subjects were labeled with In-111 8-hydroxyquinoline (In-111 oxine) in the presence of plasma in either "closed" blood transfer packs or in "open" test tubes. The mean labeling efficiencies in these two systems were 27 and 53%, respectively. Mean survival time of In-111-labeled autologous platelets was 8.76 days, with a standard deviation of 1.05 according to the maximum-likelihood estimate of the gamma-function model. The initial recovery of In-111 platelets in the circulation was 57% with a standard deviation of 11%. The distribution of In-111 platelets in liver and spleen was quantitated by anterior, posterior, and transmission gamma-camera imaging. During the first 30 min, 38% of the injected dose accumulated in the spleen, 13% in the liver. No significant increase in In-111 radioactivity was observed in either of the two organs over a 3-9-day period. The bone marrow was an additional site of In-111 accumulation. The spleen was the critical organ with respect to radiation dose. The splenic dose was estimated to be 34 rad/mCi In-111 platelets, that of the liver 2.1 rad/mCi. With the injection of 100-150 microCi of In-111-labeled platelets in normal subjects, giving a splenic radiation of 5 rad, a complete 10-day survival study can be performed and uptake of In-111 in different organs can be measured quantitatively for at least 3-4 days.

Adult↗
PubMed1982

[Contributions to the liberation of drugs from suspension ointments. Part 19: Studies on the interactions of hydroxyquinoline (salts) with ointment components (author's transl)].

On studying the interactions of hydroxyquinoline and its watersoluble salts with substances commonly used to ointment preparation, the authors stated a large agreement between the decreases in release rate and the quotients of binding determined by equilibrium dialysis. Sodium carboxymethyl cellulose, zinc oxide, and talc react with these drugs to form bindings of some strength the impair the release of the drugs, whereas hydroxyethylcellulose and Aerosil behave indifferently.

Chemistry, Pharmaceutical↗
PubMed1997

A new indirect spectrofluorimetric determination of sub-micromolar concentrations of manganese(II) in bovine liver by means of 2-hydroxyquinoline.

A new high-sensitive and at the same time accurate and well documented indirect spectrofluorimetric method for the determination of sub-micromolar concentrations of manganese(II) being as a normal trace element in the bovine liver, was described. The purpose of the experimental work is performed by means of two fluorescence intensity measurements; the measurement of the fluorescence (F1) of a 2.0 x 10(-5) mol/l solution of pure 2-hydroxyquinoline (2-HQ) (lambda ex: 320 nm: lambda em: 375 nm), and that of the fluorescence of the above solution after the addition of Mn(II) to be analyzed (F2). The observed difference of the fluorescence intensities measured (F1-F2) = delta F, is exclusively owed to the quenching of the Mn(II) on the free 2-HQ. The presence of various metal ions considerably interferes with the above described determination of Mn(II). For this reason, the separation and/or masking of these undesirable metal ions it is advisable to apply before any analytical praxis.

Animals↗
PubMed2007

A novel strategy for the design of 8-hydroxyquinolinate-based lanthanide bioprobes that emit in the near infrared range.

A new polydentate tripodal ligand T2soxMe was synthesized to take advantage of the chelating effect of tridentate 8-hydroxyquinolinate subunits. Potentiometric and spectrophotometric titrations reveal seven pK(a) values of between 3.7 and 10.2. In water, the use of T2soxMe leads to thermodynamically stable and soluble Ln(III) complexes at physiological pH, with conditional stability constants in the range log beta(11)=7.8-8.6. The chelates are resistant toward hydrolysis and show interesting photophysical properties, particularly in the near infrared (NIR) range. The emission lifetimes of the Nd(III) and Yb(III) complexes recorded in D(2)O and H(2)O suggest the absence of water molecules in the first coordination sphere of the metal ions. Moreover, the low energy of the triplet state allows efficient energy transfer from the ligand to the metal ions: in water at pH 7.4, the sensitization efficacy of the NIR luminescence reaches 75 and approximately 100 % for Nd(III) and Yb(III), respectively, leading to overall quantum yields of 0.027 and 0.13 %; Er(III) luminescence is also detected. According to the WST-1 test, the Yb(III) podate at concentrations of up to 250 microM does not display sizeable cytotoxicity for Jurkat cells after 24 h of incubation. Finally, the same podate is shown to couple to human serum albumin, leading to an increase of 50 % in the NIR-luminescence intensity.

Biosensing Techniques↗
PubMed2003

Excited-state proton-relay dynamics of 7-hydroxyquinoline embedded in a solid matrix of poly(2-hydroxyethyl methacrylate).

Excited 7-hydroxyquinoline embedded in a solid matrix of poly(2-hydroxyethyl methacrylate) undergoes a proton-relay reaction efficiently to form its keto tautomer. However, the reaction mechanism depends on the torsional conformation and the microscopic environment of the molecule at the moment of excitation. Whereas the bridged cis-enol form undergoes proton relay immediately on absorption of a photon to produce its tautomeric keto species, the unbridged cis form requires 120 ps for bridge formation via solvent reorganization prior to proton relay. Furthermore, the trans form needs 1000 ps for tautomerization because it requires an activated (11 kJ mol-1) torsional motion to change into its cis form prior to bridge formation and proton relay. Torsional motion rather than solvent reorganization determines the proton relay rate of the trans-form of the molecule.

Journal Article↗
PubMed1994

Solubilities and solvation of aluminum(III), iron(III), and indium(III) 8-hydroxyquinolinates in methanol/water mixtures.

Solubilities are reported for aluminum, indium, and iron(III) complexes of 8-hydroxyquinoline and its 5-nitro, 5-sulfonato, and 7-iodo-5-sulfonato derivatives in water, methanol, and water/methanol mixtures, at 298.2 K. Transfer chemical potentials for the respective complexes have been derived from these data, and their trends are discussed in terms of solvation of the complexes by water and methanol.

Aluminum↗
PubMed1994

Extraction of magnesium from biological fluids using 8-hydroxyquinoline and cation-exchange chromatography for isotopic enrichment analysis using thermal ionization mass spectrometry.

The use of 8-hydroxyquinoline to precipitate magnesium was evaluated as a method for preparing biological samples for isotopic enrichment analysis using thermal ionization mass spectrometry (TIMS). Standard curves in matrices of water, serum, and urine were prepared using varying amounts of 25Mg. The 25Mg/24Mg isotope ratio was measured by TIMS using a silica gel/phosphoric acid technique. Although the total Mg recovered by precipitation from the matrices varied considerably and was dependent on matrix, recovery was sufficient for isotopic enrichment analysis. Urine samples required cation-exchange chromatography (Bio-Rex AG 50W-X8 filter membrane, Bio-Rad Laboratories) prior to precipitation to remove contaminants which interfered with the thermal ionization process. The observed versus expected 25Mg/24Mg enrichments were evaluated using linear regression analysis: water, y = 0.016 + 1.022x; serum, y = 0.5 + 1.097x; urine, y = -0.004 + 0.943x. This method has proven useful for the isolation of magnesium from the biofluids tested.

Body Fluids↗
PubMed2002

On-line pre-concentration of Cr(III) and Mn(II) in FI-FAAS: A critical study involving interference effects and analytical use of an immobilized 8-hydroxyquinoline minicolumn.

A flow injection system with a pre-concentration minicolumn based on a chelating resin was coupled to a flame atomic absorption spectrometer. The focus of this work was the investigation of interference effects and the analytical applicability of the azo-immobilized 8-hydroxyquinoline on controlled-pore glass for the determination of Cr and Mn in mussel and non-fat milk powder. All studied concomitants affected the retention of Cr(III). These effects are probably related to the formation of hydroxo-complexes at the optimum pH range 9.0-10. The positive effect caused by Ca(II) was exploited to increase the retention of Cr(III) species and to improve the slope by 70%. The interferences on Mn(II) retention were less severe. The quantification of Cr and Mn was performed by standard additions. The proposed methodology was validated by analysis of three certified reference materials of mussels (Cr and Mn) and non-fat milk powder (Mn) with a mean relative percent error of <6.5% and mean relative standard deviation of <13%. Chromium and Mn were determined in typical Chilean mussels samples, and Mn was determined in non-fat milk powder samples. Results agreed at the 95% confidence level with those obtained by electrothermal atomic absorption spectrometry (ETAAS) using graphite furnace atomization. The method detection limits for a 30 s pre-concentration time were 0.9 and 1.1 micro g L(-1) for Mn, and 2.2 and 2.5 micro g L(-1) for Cr in acid digested solutions of mussel and non-fat milk, respectively. The methodology is simple, fast (sampling frequency 60-72 h(-1)), reliable, of low cost, and can be applied to the determination of traces of Cr (> or =0.18 micro g g(-1)) and Mn (> or =0.6 micro g g(-1)) in mussel samples, and Mn (> or =0.37 micro g g(-1)) in non-fat milk powder.

Animals↗
PubMed1990

Anti-proliferative effects and phenotypic alterations induced by 8-hydroxyquinoline in melanoma cell lines.

The effect of the transition metal chelator, 8-hydroxyquinoline (8-HQ), was examined on the growth and phenotype expression of B16 mouse melanoma cells. Micromolar concentrations of 8-HQ inhibited the growth of B16 cells as well as human melanoma cell lines. Removal of 8-HQ from the culture medium restored normal cell growth. Growth inhibition by 8-HQ was accompanied by phenotypic alterations that included changes in cell morphology, increased production of melanin and enhanced activities of the enzymes gamma-glutamyl transpeptidase and NADPH cytochrome c reductase. These changes might be associated with a better differentiated phenotype.

Animals↗
PubMed2006

Aluminum determination in biological fluids and dialysis concentrates via chelation with 8-hydroxyquinoline and solvent extraction/fluorimetry.

We describe a simple, rapid, and sensitive fluorescence method for measurement of aluminum (Al) in human biological fluids, in dialysis solutions, and in tap water, which uses 8-hydroxyquinoline for ion chelation. The fluorescence intensity of the toluene-extracted metal chelate (excitation wavelength, 380 nm; emission wavelength, 504 nm) remains unchanged for over 48 h at room temperature. Fluorescence intensity is a linear function of the concentration of Al in the 2-1000 microg/L range with detection limits of 0.7-2 microg/L. A large excess of other ions normally found in biological fluids does not interfere in Al determination. The method developed was successfully used in assaying Al in serum and urine of reference subjects, in serum samples from patients undergoing long-term dialysis, and in dialysis solutions. Al concentrations, measured by this fluorimetric procedure, were compared with those obtained by Zeeman graphite-furnace atomic absorption spectrometry. A correlation coefficient of 0.98 was obtained. The proposed method could be used for routine analysis in clinical laboratories for accurate determination of aluminum in aqueous or biological fluids.

Aluminum↗
PubMed2005

8-Hydroxyquinoline inhibits iNOS expression and nitric oxide production by down-regulating LPS-induced activity of NF-kappaB and C/EBPbeta in Raw 264.7 cells.

In activated macrophage, large amounts of nitric oxide (NO) are generated by inducible nitric oxide synthase (iNOS), resulting in acute or chronic inflammatory disorders. In Raw 264.7 cells stimulated with lipopolysaccharide (LPS) to mimic inflammation, 8-hydroxyquinoline (8HQ) inhibited the LPS-induced expression of both iNOS protein and mRNA in a parallel dose-dependent manner. 8HQ did not enhance the degradation of iNOS mRNA. To investigate the mechanism by which 8HQ inhibits iNOS gene expression, we examined the activation of MAP kinases in Raw 264.7 cells. We did not observe any significant change in the phosphorylation of MAPKs between LPS alone and LPS plus 8HQ-treated cells. Moreover, 8HQ significantly inhibited the DNA-binding activity of nuclear factor-kappaB (NF-kappaB) and CCAAT/enhancer-binding protein beta (C/EBPbeta), but not activator protein-1 and cAMP response element-binding protein. Taken together, these results suggest that 8HQ acts to inhibit inflammation through inhibition of NO production and iNOS expression through blockade of C/EBPbeta DNA-binding activity and NF-kappaB activation.

Animals↗
PubMed2005

Conversion of tris(8-quinolinolato-N1, O8) aluminum to 8-hydroxyquinoline and activity in bacterial reverse mutation assays.

Tris(8-quinolinolato-N1, O8) aluminum (AlQ), an aluminum chelate of 8-hydroxyquinoline (8OHQ) is an important charge transfer molecule in semiconducting imaging devices. This study was conducted to evaluate AlQ and 8OHQ for the ability to induce reverse mutations, either in the presence or absence of mammalian microsomal enzymes, and to determine if AlQ decomposes or is metabolized to 8OHQ under assay conditions. The tester strains used in the mutation assay were Salmonella typhimurium TA98, TA100, TA1535 and TA1537 and Escherichia coli WP2uvrA (pKM101). The assays were conducted in the presence and absence of S9. AlQ doses were 1-1000 microg per plate while 8OHQ doses were 0.947-947 microg per plate to maintain molar equivalency. Stability studies were carried out for 4h at 37 degrees C under conditions designed to mimic mutation assays. Samples were analyzed by HPLC and LC/MS to tentatively identify potential metabolites of AlQ and 8OHQ. The results of the bacterial mutagenicity assay indicate that in the presence of S9, both AlQ and 8OHQ, caused increases in the mean number of revertants per plate with tester strains TA100 and WP2uvrA (pKM101). No increases were observed with any of the remaining tester strain/activation condition combinations. The stability study showed that AlQ degrades readily to 8OHQ under standard mutagenicity test conditions, and the positive test result with AlQ is due to the bioactivation of 8OHQ. In the presence of S9, 8OHQ is metabolized to one detectable product with molecular weight indicative of a one-oxygen insertion. 8OHQ N-oxide and 2,8-quinolinediol were ruled out as possible metabolites; 8OHQ epoxides and other quinolinediols were neither confirmed nor ruled out. Bacterial mutagenicity tests have not been shown to predict in vivo effects of 8OHQ; these assays are similarly expected to be poorly predictive of in vivo genotoxic and carcinogenic potential of AlQ.

Animals↗
PubMed2005

HF and DFT studies of the structure and vibrational spectra of 8-hydroxyquinoline and its mercury(II) halide complexes.

The geometry, frequency and intensity of the vibrational bands of 8-hydroxyquinoline (8-HOQ) were obtained by HF and density functional theory (DFT) with BLYP and B3LYP functionals and 6-31G(d) as the basis set. The optimized bond lengths and bond angles are in good agreement with the X-ray data. The vibrational spectra of 8-HOQ which is calculated by the HF and DFT methods, reproduces the vibrational wavenumbers and intensities with an accuracy, which allows reliable vibrational assignments. Complexes of the type Hg(8-HOQ)X(2) [where X = Cl , Br] have been studied in the 4000-200 cm(-1) region, and assignment of all the observed bands were made. The analysis of the infrared spectra indicates that there are some structure-spectra correlations.

Mercury↗
PubMed2005

DFT studies and vibrational spectra of isoquinoline and 8-hydroxyquinoline.

The geometry, frequency and intensity of the vibrational bands of isoquinoline (IQ) and 8-hydroxyquinoline (8-HQ) were obtained by the density functional theory (DFT) calculations with the B3LYP functional and 6-31 G* basis set. The vibrational spectral data obtained from the solid phase mid and far FT-IR and FT-Raman spectra of IQ and 8-HQ are assigned based on the results of the normal coordinate calculations. The observed and the calculated spectra are found to be in good agreement.

Carbon↗
PubMed2005

Growth and spectroscopic characterization of a new organic nonlinear optical crystal--8-hydroxyquinoline.

A novel organic nonlinear optical crystal 8-hydroxyquinoline having good optical quality has been grown by slow evaporation solution technique using methanol as solvent. The morphology of the grown crystals were identified by X-ray diffraction method. Solubility studies were made under various solvents and solvent mixtures at different temperatures. Functional groups present in the grown material have been identified using FTIR and FT Raman spectra. Transparency was tested using UV-vis spectrophotometer and the second harmonic generation was also verified.

Crystallization↗
PubMed2006

Fluoride ion detection by 8-hydroxyquinoline-Zr(IV)-EDTA complex.

A simple fluorescent detection based on the ligand exchange mechanism is proposed for the fluoride ion in aqueous media. This procedure is based on the exchange of 8-hydroxyquinoline (oxine) coordinated to Zr(IV) by fluoride ion without interference from other common anions. The ternary complex of oxine with [Zr(H(2)O)(2)EDTA].2H(2)O formed by replacing two water molecules in aqueous solution provides a sensitive signalling system for fluoride ion in the concentration range from 6 x 10(-7)M to 8 x 10(-4)M. The green fluorescence (lambda(max)=532 nm) exhibited by the complex upon excitation at 247 nm decreases in intensity with fluoride addition with a detection limit of 12 ppb. The complexation reaction between oxine and Zr(IV)-EDTA and the ligand exchange reaction with fluoride ion has been investigated by UV-vis and fluorescence spectroscopies combined with the PM3 semi-empirical quantum chemical calculations. Job's method of continuous variation and the molar ratio method ascertain a 1:1 stoichiometry composition of the chelate in aqueous media.

Fluorides↗
PubMed2006

Kinetics of the substitution of dehydroacetic acid in tris (dehydroacetato) Fe(III) complex by 8-hydroxyquinoline, di- and tetra-hydroxyquinone.

The ligand substitution reactions of dehydroacetic acid (Hdha) in [Fe(dha)(3)] with second ligand such as 8-hydroxyquinoline (Hquin), 1,4-dihydroxyanthraquinone (H(2)dhaq) and 1,4,5,8-tetra-hydroxyanthraquinone (H(4)thaq) were investigated spectrophotometrically by in low polarity solvents like benzene, chloroform and dichloromethane. It is deduced that the substitution reaction takes place through one successive step. The reaction was performed at four different temperatures (5-25) degrees C, and it exhibits a first order dependence on the concentration of the starting complex. The observed rate constant depends on the concentration of both leaving and entering ligands. The evaluation of the kinetic data gives activation parameters which support an associative mechanism in the transition states and the higher rate of substitution of the dha in Fe(dha)(3) complex is due to entropy effect. The solid complexes were synthesized and characterized by elemental analysis, IR and UV-vis spectral techniques.

Anthraquinones↗