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1

Synergistic antifungal action of 8-quinolinol and its bischelate with copper(II) and with mixed ligand chelates composed of copper(II), 8-quinolinol, and aromatic hydroxy acids.  

PubMed

Antifungal studies were made of mixtures of minimal inhibitory concentrations (MICs) of 8-quinolinol and its bischelates with copper(II), zinc(II), and manganese(II) and with mixed ligand chelates composed of 8-quinolinol, copper(II) and a second ligand including salicylic acid, 3-hydroxy-2-naphthoic acid, 3,5-diiodosalicylic acid, and 4-bromo-3-hydroxy-2-naphthoic acid. Mixtures of the MICs of the bischelates of 8-quinolinol with copper(II) and zinc(II) and copper(II) and manganese(II), as well as 7-iodo-8-quinolinol and its bischelate with copper(II), and 8-quinolinol and 5-iodo-8-quinolinol were also studied against six fungi: Aspergillus niger, Aspergillus oryzae, Trichoderma viride, Myrothecium verrucaria, Mucor cirinelloides, and Trichophyton mentagrophytes. With the exceptions of the mixtures of 8-quinolinol and (8-quinolinolato)(3,5-diiodosalicylato)copper(II) and (8-quinolinolato)(4-bromo-3-hydroxy-2-naphthoato)copper(II) against M. cirinelloides, all of the test organisms were inhibited by 40% or less of each mixture containing 8-quinolinol. Bischelates of 8-quinolinol with copper(II) and zinc(II) and copper(II) and manganese(II) inhibited five fungi at 50% of the mixtures of the MICs. Mucor cirinelloides was not inhibited by bis(8-quinolinolato)copper(II), bis(8-quinolinolato)zinc(II), or by bis(7-iodo-8-quinolinolato)copper(II).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2516124

Gershon, H; Clarke, D D; Gershon, M

1989-11-01

2

Molecular geometries, vibrational analysis, bonding and molecular orbitals of the three isomers of [RuCl(qn) 2NO] (Hqn=2-methyl-8-quinolinol or 2-chloro-8-quinolinol): density functional theory studies  

Microsoft Academic Search

The geometries of the three isomers of [RuCl(qn)2NO] {Hqn=2-methyl-8-quinolinol (H2mqn) or 2-chloro-8-quinolinol (H2cqn)} were calculated with the restricted Hartree–Fock and different DFT methods. The B3PW91 method gave the best performance in the calculation for predicting the structure and vibrational spectrum of this series of complexes. The deviation between the calculated and the observed NO harmonic stretching frequencies was about 1%

Hongfei Wang; Eiichi Miki; Suyong Re; Hiroaki Tokiwa

2002-01-01

3

THE THERMAL DECOMPOSITION OF THE 5,7-DIHALO-8QUINOLINOL RARE EARTH METAL CHELATES  

Microsoft Academic Search

S>The thermal decomposition of the 5,7-dichloro-, 5,7dibromo- and 5,7-; diiodo-8-quinolinol chelates of La, Ce, Pr, Nd, Sm, and Y was investigated on the ; thermobalance. The chelates decomposed in the temperature range from 65 to 125 ; deg C while the oxide levels were obtained from 395 to 805 deg C. Although the ; chelate thermal stability temperatures varied little

W Wendlandt

1957-01-01

4

Structure, magnetic behavior, and anisotropy of homoleptic trinuclear lanthanoid 8-quinolinolate complexes.  

PubMed

Three complexes of the form [Ln(III)3(OQ)9] (Ln = Gd, Tb, Dy; OQ = 8-quinolinolate) have been synthesized and their magnetic properties studied. The trinuclear complexes adopt V-shaped geometries with three bridging 8-quinolinolate oxygen atoms between the central and peripheral eight-coordinate metal atoms. The magnetic properties of these three complexes differ greatly. Variable-temperature direct-current (dc) magnetic susceptibility measurements reveal that the gadolinium and terbium complexes display weak antiferromagnetic nearest-neighbor magnetic exchange interactions. This was quantified in the isotropic gadolinium case with an exchangecoupling parameter of J = -0.068(2) cm(-1). The dysprosium compound displays weak ferromagnetic exchange. Variable-frequency and -temperature alternating-current magnetic susceptibility measurements on the anisotropic cases reveal that the dysprosium complex displays single-molecule-magnet behavior, in zero dc field, with two distinct relaxation modes of differing time scales within the same molecule. Analysis of the data revealed anisotropy barriers of Ueff = 92 and 48 K for the two processes. The terbium complex, on the other hand, displays no such behavior in zero dc field, but upon application of a static dc field, slow magnetic relaxation can be observed. Ab initio and electrostatic calculations were used in an attempt to explain the origin of the experimentally observed slow relaxation of the magnetization for the dysprosium complex. PMID:24520896

Chilton, Nicholas F; Deacon, Glen B; Gazukin, Olga; Junk, Peter C; Kersting, Berthold; Langley, Stuart K; Moubaraki, Boujemaa; Murray, Keith S; Schleife, Frederik; Shome, Mahasish; Turner, David R; Walker, Julia A

2014-03-01

5

Substitutional complexometric determination of magnesium in homogeneous water-dioxan medium, based on decomposition of MgEDTA with 8-quinolinol and titration of released EDTA with calcium.  

PubMed

A method based on a substitution reaction between MgEDTA and 8-quinolinol, and titration of the liberated EDTA with calcium is proposed. The reaction is performed in homogeneous 50%-60% dioxan medium at ph 10, in which magnesium forms a soluble and stable 8-quinolinol complex. PMID:18965572

Karolev, A

1992-12-01

6

8-Quinolinolate complexes of yttrium and ytterbium: molecular arrangement and fragmentation under laser impact.  

PubMed

New 8-quinolinolate (Q) complexes of yttrium (1) and ytterbium (2) were synthesized by the reactions of Cp3Y and Yb[N(SiMe3)2]3 with 3 equiv. of 8-hydroxyquinoline in a DME solution. Single crystal X-ray analysis revealed the trinuclear molecular structure of the compounds Ln3Q9. The LDI-TOFMS investigation displayed that under the laser impact the compounds split off Q(-) anions to give Ln3Q8(+), Ln2Q5(+) and LnQ3(+) moieties. In the negative mode spectra the anions Q(-) and LnQ4(-) were observed. The DFT calculations showed the decreased stability of cationic Ln-quinolinolate as compared with their anionic counterparts. Complex 2 which is used as an emitter in a three-layer OLED displayed a metal-centered emission at 979 nm and an intensity of 50 ?W cm(-2) at 15.5 V. PMID:24048370

Baranov, Evgeny V; Fukin, Georgy K; Balashova, Tatyana V; Pushkarev, Anatoly P; Grishin, Ivan D; Bochkarev, Mikhail N

2013-11-28

7

Electrochemistry of oxo-technetium(V) complexes containing Schiff base and 8-quinolinol ligands  

SciTech Connect

The electrochemistry of six-coordinate, monooxo technetium(V) complexes containing Schiff base ligands has been studied in acetonitrile and N,N'-dimethylformamide solutions. The complexes have the general formula TcOCl(L/sub B/)/sub 2/ or TcO(L/sub T/)(L/sub B/), where L/sub B/ represents a bidentate-N,O Schiff base ligand or a bidentate-N,O 8-quinolinol ligand and L/sub T/ represents a tridentate-O,N,O Schiff base ligand. Cyclic voltammetry at a platinum-disk electrode, controlled-potential coulometry, and thin-layer spectroelectrochemistry were used to probe both the oxidation and the reduction of these complexes. The results of these studies, and previously reported results on the analogous Re(V) complexes, can be understood within a single general reaction scheme. The salient features of this scheme are (i) one-electron reduction of Tc(V) to Tc(IV), (ii) subsequent loss of a ligand situated cis to the Tc/identical to/O linkage, and (iii) subsequent isomerization of this unstable Tc(IV) product to more stable complex in which the site trans to the Tc/identical to/O linkage is vacant. The Tc(IV) complexes can also be reduced to analogous Tc(III) species, which appear to undergo the same ligand loss and isomerization reactions. The technetium complexes are 400-500 mV easier to reduce than are their rhenium analogues. The 8-quinolinol ligands, and especially the 5-nitro derivative, both thermodynamically and kinetically stabilize the Tc(IV) and Tc(III) oxidation states. These electrogenerated species are unusual in that they constitute the bulk of the known examples of monomeric Tc(IV) and Tc(III) complexes containing only N- and O-donating ligands. 34 refs., 9 figs., 1 tab.

Refosco, F.; Mazzi, U.; Deutsch, E.; Kirchhoff, J.R.; Heineman, W.R.; Seeber, R.

1988-11-16

8

Effect of Alkyl Substituents on the Selective Extraction of Copper(ll), Palladium(ll), Gallium(lll) and Molybdenum(VI) with Novel 8Quinolinol Derivatives  

Microsoft Academic Search

The partition coefficient between heptane or chloroform and 0.1 M NaCI aqueous solution, and the acid dissociation constants of 5-alkyloxymethyl-8-quinolinol (HO„Q) were determined. Also, the extraction and back-extraction behavior, extraction equilibrium and kinetics, and the separation of Cu{11) [1, 2], Mo(VI), [3, 4], Pd(II), [5], Ga(IlI) [6], Co(Il) [7] and Ni(ll) [7] with novel 8-quinolinol derivatives (HA) have been investigated. Cu(II)

K. OHASHI; H. IMURA; S. MOCHIZUKI; K. HIRATANI

1997-01-01

9

Synergistic effect of 3,5-dichlorophenol and trioctylphosphine oxide on the extraction of vanadium(V) with 2-methyl-8-quinolinol derivatives.  

PubMed

The extraction of vanadium(V) with 2-methyl-8-quinolinol derivatives (HA), such as 2-methyl-8-quinolinol (HMQ), 2-methyl-5-butyloxymethyl-8-quinolinol (HMO4Q), and 2-methyl-5-hexyloxymethyl-8-quinolinol (HMO6Q), from a weakly acidic solution into chloroform was studied in both the absence and presence of 3,5-dichlorophenol (Hdcp) and trioctylphosphine oxide (TOPO) as the synergists. Vanadium(V) was extracted with HA as VO(OH)(A)2 in the absence of synergists, and its extractability increased with an increase in the hydrophobicity of HA. Vanadium(V) was quantitatively extracted from the lower pH region upon the addition of Hdcp and TOPO as VO(OH)(A)2 x Hdcp and VO2(A)(TOPO), respectively. The enhancement of the synergistic effect of Hdcp on the extraction of vanadium(V) with HA increased in the following order: HMQ < HMO4Q < HMO6Q, as opposed to that of TOPO. This result was ascribable to the difference in the mechanisms of the occurrence of the synergistic effect by Hdcp and TOPO. PMID:12458708

Tsuguchi, Akira; Ohashi, Akira; Choi, Sung-Yong; Imura, Hisanori; Ohashi, Kousaburo

2002-11-01

10

Kinetics of the interaction of indium(III) with 8-quinolinol-5-sulfonic acid and with sulfate.  

PubMed

The kinetics and equilibria of indium(III) binding to 8-quinolinol-5-sulfonic acid (HQSA) have been investigated in acidic aqueous solution at 0.2 M ionic strength and 25 C by stopped-flow, absorption and fluorescence spectrometric methods. Absorption and fluorescence spectrometry revealed that a monoprotonated MHL3+ complex is formed in addition to the ML2+ chelate. The stability constants of the chelate (log K(ML) 6.53). of the monoprotonated complex (logK(MHL = 3.5l) and its acid dissociation constant (pK(C2) = 1.4) have been determined. Stopped-flow measurements indicate three reaction paths that involve the interaction of M3+ with H2L+ (k1 =(3.21 +/- 0.04) x 10(2) m(-1) s(-1)), M3+ with HL (k2=(6.52 +/- 0.04) x 10(4) M(-1)s(-1)) and MOH2+ with HL (k3 = (1.60 +/- 0.08) x 10(6) M(-1) s(-1)), respectively. The reactivity of In3+ toward the uncharged form of HQSA has been found to be approximately two orders of magnitude less than expected based upon water exchange experiments. This behaviour has been explained with the assumption that the ligand is distributed between two forms (neutral and zwitterion) of which only the neutral form is reactive. The rate of complex formation between In3+ and SO4(2-) ion has been measured by the temperature-jump method with Tropaeolin 00 as the indicator. The second-order rate constant of the binding process is 5.1 x 10(4) M s(-1). This quantity yields a value for the first-order rate constant of 570 s(-1) for ligand penetration into the In3+ coordination shell, approximately two orders of magnitude less than normal. This finding is interpreted by the hypothesis that SO4(2-) forms a chelate with In3+ for which ring closure is the rate-determining step. PMID:11757653

Ricciu, A; Secco, F; Venturini, M; García, B; Leali, J M

2001-11-01

11

Determination of rare earth elements in seawater by inductively coupled plasma mass spectrometry with on-line column pre-concentration using 8-quinolinole-immobilized fluorinated metal alkoxide glass  

NASA Astrophysics Data System (ADS)

The on-line column pre-concentration technique with inductively coupled plasma mass spectrometry (ICP-MS) has been developed using micro-column of 8-quinolinole-immobilized fluorinated metal alkoxide glass (MAF-8HQ). The aim of method was to determine rare earth elements (REEs) (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in seawater. A 6.4 ml of seawater sample was passed through the column for 2 min, after washing the column with ultrapure water, the adsorbed REEs were subsequently eluted into the plasma with 1.4 M nitric acid. Sample pH, sampling and eluting flow rates and acidity of eluent were optimized. Detection limits (3 ?) based on three times standard deviations of water by 8 replicates were in the range from 0.11 pg ml -1 for Y to 0.30 pg ml -1 for Tb, and the precisions by a 10 pg ml -1 REEs standard solution ( n=8) were in the range from 4.7% for Tm to 8.7% for Tb and Yb. Analysis of one sample could be processed in 7 min. The proposed method was verified by determination of REEs in the two certified reference materials (CRMs) of seawater, CASS-4 and NASS-5, and the method was also applied to determine REEs in the costal seawater of Hiroshima Bay, the Seto Inland Sea, Japan.

Kajiya, Tasuku; Aihara, Masato; Hirata, Shizuko

2004-04-01

12

Studies of the degradation mechanism of organic light-emitting diodes based on tris(8-quinolinolate)aluminum Alq and 2-tert-butyl-9,10-di(2-naphthyl)anthracene TBADN  

NASA Astrophysics Data System (ADS)

Previously, radical cation of tris(8-quinolinolate)aluminum (Alq•+) has been associated with the instability of Alq films subjected to holes-only electrical current. Yet, the questions remain (i) whether Alq•+ is the primary source of the intrinsic degradation of bipolar organic light-emitting diodes (OLEDs) based on Alq, (ii) whether Alq•+ reactions result in deep charge traps in holes-only devices as found in bipolar counterparts, and (iii) whether radical cations can be a common source of degradation of OLEDs irrespective of materials. With regards to generality of hole-current-related degradation, it is interesting to examine the behavior of 9,10-diarylanthracenes (DAAs)-the practically important class of blue-fluorescing light-emitting-layer hosts. These questions prompted our comparative study of the effects of unipolar currents in Alq and 2-t-butyl-9,10-di(2-naphthyl)anthracene (TBADN), which was chosen as a representative material of the DAA class. First, we identified device structures allowing for rigorous and stable unipolar conduction. Interestingly, even in pristine holes-only devices, our voltammetric measurements indicated that Alq contains a substantial density of deep hole traps (far deeper than what can be explained by energetic disorder), which can be charged by passing holes-only current and seemingly discharged by exposure to white light. As for aged holes-only Alq devices, they exhibited symptoms qualitatively matching those of aged bipolar Alq devices, viz., photoluminescence (PL) loss, transition voltage (V0) rise, and drive voltage (Vd) rise. Notably, PL and V0 are linearly correlated in both holes-only and bipolar devices, which reinforces the supposed link between Alq•+ and the degradation in both types of devices. Yet, there are indications the Alq•+ instability may not be the only degradation pathway in bipolar devices. Even though our observations for holes-only Alq devices agree qualitatively with previously reported ones, we observe far slower degradation rates [Alq PL fades up to ~500 times slower in holes-only devices, while Alq electroluminescence (EL) fades ~50 times slower in bipolar control devices]. It is possible that impurities play a significant, perhaps crucial role in the degradation mechanism of both bipolar and holes-only devices, especially the relatively shorter-lived ones. In sharp contrast to Alq, all three observables (PL, V0, and Vd) indicate that holes-only current in TBADN (neat or doped with a perylene-based blue dopant) does not result in degradation in the time that is sufficient for the corresponding bipolar control devices to lose 60%-80% of EL and 20%-30% of PL. We find that the electrons-only current in Alq or TBADN does not result in degradation either. Thus, the degradation of Alq and DAA bipolar devices may be caused by fundamentally dissimilar mechanisms: while hole current may damage the former, it does not appear to affect the latter, suggesting that the initiation step is different.

Jarikov, Viktor V.; Kondakov, Denis Y.

2009-02-01

13

Antimicrobial Activity of 8-Quinolinols, Salicylic Acids, Hydroxynaphthoic Acids, and Salts of Selected Quinolinols with Selected Hydroxy-Acids  

PubMed Central

Seventy-seven compounds were screened by the disc-plate method against strains of five bacteria and five fungi. A new constant was proposed to describe the antimicrobial activity of a compound in a defined system of organisms. This constant includes not only the inhibitory level of activity of the material but also the number of organisms inhibited. This constant, the antimicrobial spectrum index, was compared with the antimicrobial index of Albert.

Gershon, Herman; Parmegiani, Raulo

1962-01-01

14

Prooxidant action of xanthurenic acid and quinoline compounds: role of transition metals in the generation of reactive oxygen species and enhanced formation of 8-hydroxy-2'-deoxyguanosine in DNA.  

PubMed

Xanthurenic acid, a product of tryptophan-NAD pathway, and quinoline compounds produced reactive oxygen species as a complex with iron. Aconitase, the most sensitive enzyme to oxidative stress was inactivated effectively by xanthurenic acid and to a lesser extent by 8-quinolinol in the presence of ferrous sulfate. The inactivation of aconitase was iron-dependent, and was prevented by TEMPOL, a scavenger of reactive oxygen species, suggesting that reduced iron bound to xanthurenic acid or 8-quinolinol can activate oxygen molecule to form superoxide radical. However, kynurenic acid and quinaldic acid without 8-hydroxyl group did not produce reactive oxygen species. Of the quinoline compounds tested, xanthurenic acid and 8-quinolinol with 8-hydroxyl group stimulated the autooxidation of ferrous ion, but kynurenic acid and quinaldic acid did not affect the oxidation of ferrous ion. Hydroxyl group at 8-positions of quinoline compounds was essential for the binding of iron causing the generation of reactive oxygen species. 8-Quinolinol effectively enhanced the ascorbate/copper-mediated formation of 8-hydroxy-2'-deoxyguanosine in DNA, suggesting the quinolinol/copper-dependent stimulation hydroxyl radical formation. Xanthurenic acid and 8-quinolinol as the metal-chelate complexes can show various cytotoxic effects by generating reactive oxygen species through the ferrous or cuprous ion-dependent activation of oxygen molecule. PMID:16841252

Murakami, Keiko; Haneda, Miyako; Yoshino, Masataka

2006-08-01

15

THE DETERMINATION OF ALUMINUM, IRON, AND SILICON IN SILVER-CADMIUM-INDIUM ALLOYS  

Microsoft Academic Search

Aluminum, iron, and silicon were determined by standard procedures with ; the modifications required by the nature of the matrix material. Aluminum and ; iron were determined colorimetrically wiih 8-quinolinol and orthophenanthrolene, ; reapectively, after appropriate separations. Silicon was determined ; gravimetrically. The methods have been tested on synthetic samples of known ; corposition and found to give acceptable results.

Ciaranello

1959-01-01

16

Development of InP solid state detector and liquid scintillator containing indium complexes for a measurement of pp/7Be solar neutrinos  

NASA Astrophysics Data System (ADS)

Am semi-insulating indium phosphide detector has been developed for IPNOS experiment and it could detect both ?'s and the scintillation light. We have also developed an organic liquid scintillator which contains indium and zirconium complexes, and found the gamma-ray-induced luminescence of 8-quinolinol metal complexes.

Fukuda, Yoshiyuki; Ipnos Collaboration

2012-08-01

17

Prooxidant action of xanthurenic acid and quinoline compounds: Role of transition metals in the generation of reactive oxygen species and enhanced formation of 8-hydroxy-2?-deoxyguanosine in DNA †  

Microsoft Academic Search

Xanthurenic acid, a product of tryptophan–NAD pathway, and quinoline compounds produced reactive oxygen species as a complex\\u000a with iron. Aconitase, the most sensitive enzyme to oxidative stress was inactivated effectively by xanthurenic acid and to\\u000a a lesser extent by 8-quinolinol in the presence of ferrous sulfate. The inactivation of aconitase was iron-dependent, and\\u000a was prevented by TEMPOL, a scavenger of

Keiko Murakami; Miyako Haneda; Masataka Yoshino

2006-01-01

18

Effects of organic inhibitors on corrosion of zinc in an aerated 0.5 M NaCl solution  

Microsoft Academic Search

The effects of organic inhibitors on corrosion of zinc in an aerated 0.5 M NaCl solution were investigated by polarization measurements. The inhibitors were sodium benzoate (NaBz), sodium N-dodecanoylsarcosinate (NaDS), sodium S-octyl-3-thiopropionate (NaOTP), 8-quinolinol (8-QOH) and 1,2,3-benzotriazole (BTAH). These inhibitors formed precipitate films of Zn(II) salts or complexes on the zinc surface together with zinc hydroxide and oxide to prevent

Kunitsugu Aramaki

2001-01-01

19

Oxodiperoxo tungsten complex-catalyzed synthesis of adipic acid with hydrogen peroxide  

Microsoft Academic Search

An amphiphilic oxodiperoxo complex of tungsten using 8-quinolinol (QOH) as ligand has been synthesized and characterized by\\u000a elemental analyses, gravimetry, chemistry titration, TG\\/DSC, IR and UV-vis spectroscopy. Oxidation of cyclohexene, cyclohexanol,\\u000a cyclohexanone, cyclohexene oxide and 1,2-cyclohexane-diol to adipic acid in one-step was conducted by this complex catalyst\\u000a using 30 wt.% hydrogen peroxide in the absence of organic solvent and phase-transfer

Huaming Li; Wenshuai Zhu; Xiaoying He; Qi Zhang; Jianming Pan; Yongsheng Yan

2007-01-01

20

Supramolecular synthon pattern in solid clioquinol and cloxiquine (APIs of antibacterial, antifungal, antiaging and antituberculosis drugs) studied by ³?Cl NQR, ¹H-¹?O and ¹H-¹?N NQDR and DFT/QTAIM.  

PubMed

The quinolinol derivatives clioquinol (5-chloro-7-iodo-8-quinolinol, Quinoform) and cloxiquine (5-chloro-8-quinolinol) were studied experimentally in the solid state via ³?Cl NQR, ¹H-¹?O and ¹H-¹?N NQDR spectroscopies, and theoretically by density functional theory (DFT). The supramolecular synthon pattern of O-H···N hydrogen bonds linking dimers and ?-? stacking interactions were described within the QTAIM (quantum theory of atoms in molecules) /DFT (density functional theory) formalism. Both proton donor and acceptor sites in O-H···N bonds were characterized using ¹H-¹?O and ¹H-¹?N NQDR spectroscopies and QTAIM. The possibility of the existence of O-H···H-O dihydrogen bonds was excluded. The weak intermolecular interactions in the crystals of clioquinol and cloxiquine were detected and examined. The results obtained in this work suggest that considerable differences in the NQR parameters for the planar and twisted supramolecular synthons permit differentiation between specific polymorphic forms, and indicate that the more planar supramolecular synthons are accompanied by a greater number of weaker hydrogen bonds linking them and stronger ?···? stacking interactions. PMID:21080020

Latosi?ska, Jolanta Natalia; Latosi?ska, Magdalena; Tomczak, Marzena Agnieszka; Seliger, Janez; Zagar, Veselko

2011-07-01

21

Flame AAS determination of lead in water with flow-injection preconcentration and speciation using functionalized cellulose sorbent.  

PubMed

The on-line solid phase extraction of trace amount of lead in flow-injection system with flame AAS detection was investigated using cellulose sorbents with phosphonic acid and carboxymethyl groups, C(18) sorbent non-modified and modified with Pyrocatechol Violet or 8-quinolinol, commercial chelating sorbents Chelex 100 and Spheron Oxin 1000, non-polar sorbent Amberlite XAD-2 modified with Pyrocatechol Violet and several cation-exchange resins. The best dynamic characteristics of retention were observed for functionalized cellulose sorbents. For Cellex P assumed as optimum sorbent, elution with a separate fractions of nitric acid and ethanol allows the differentiation between tetraalkyllead and sum of inorganic lead and organolead species of smaller number of alkyl groups. The detection limit for the determination of inorganic Pb(II) was estimated as 0.17 microg/l. at preconcentration from 50 ml sample at a flow rate of 7 ml/min. PMID:18966301

Naghmush, A M; Pyrzy?ska, K; Trojanowicz, M

1995-06-01

22

Organic-solvent/water/ionic-liquid triphasic system for the fractional extraction of divalent metal cations.  

PubMed

A novel cyclohexane/water/ionic-liquid (1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6]) triphasic extraction system was studied for a possible fractional extraction of divalent metal cations with co-using 8-quinolinol (HQ) and tri-n-octylphosphine oxide (TOPO) as competitive extractants. In this system, Ni2+ was extracted into the [bmim][PF6] phase as a Q(-)-complex, whereas each of Mn2+, Zn2+, Cd2+ and Pb2+ was extracted into the cyclohexane phase as an ion-pair of a cationic TOPO-complex and PF6-. A suitable selection of extractants and ionic liquid can result in developing a powerful triphasic fractional extraction system. PMID:19907081

Takata, Takeshi; Hirayama, Naoki

2009-11-01

23

True blue: blue-emitting aluminum(III) quinolinolate complexes.  

PubMed

Blue-emitting heteroleptic aluminum(III) bis(2-methyl-8-quinolinolate)phenolate complexes were synthesized. A tunable, blue-to-green emission is achieved by attaching electron-withdrawing modulators to the emisssive quinaldinate ligand. The electronic nature of modulator substituents attached to the position of the highest HOMO (highest occupied molecular orbital) density is used to modulate ligand HOMO levels to achieve effective emission tuning to obtain blue-emitting materials. Optical and electrochemical properties of the resulting complexes were investigated and compared to the results of density functional theory (DFT/B3LYP/6-31G*) studies. The resulting materials may find application as organic light-emitting device materials. PMID:17112247

Pérez-Bolívar, César; Montes, Victor A; Anzenbacher, Pavel

2006-11-27

24

Pollutant-Induced Modulation in Conformation and ?-Lactamase Activity of Human Serum Albumin  

PubMed Central

Structural changes in human serum albumin (HSA) induced by the pollutants 1-naphthol, 2-naphthol and 8-quinolinol were analyzed by circular dichroism, fluorescence spectroscopy and dynamic light scattering. The alteration in protein conformational stability was determined by helical content induction (from 55 to 75%) upon protein-pollutant interactions. Domain plasticity is responsible for the temperature-mediated unfolding of HSA. These findings were compared to HSA-hydrolase activity. We found that though HSA is a monomeric protein, it shows heterotropic allostericity for ?-lactamase activity in the presence of pollutants, which act as K- and V-type non-essential activators. Pollutants cause conformational changes and catalytic modifications of the protein (increase in ?-lactamase activity from 100 to 200%). HSA-pollutant interactions mediate other protein-ligand interactions, such as HSA-nitrocefin. Therefore, this protein can exist in different conformations with different catalytic properties depending on activator binding. This is the first report to demonstrate the catalytic allostericity of HSA through a mechanistic approach. We also show a correlation with non-microbial drug resistance as HSA is capable of self-hydrolysis of ?-lactam drugs, which is further potentiated by pollutants due to conformational changes in HSA.

Ahmad, Ejaz; Rabbani, Gulam; Zaidi, Nida; Ahmad, Basir; Khan, Rizwan Hasan

2012-01-01

25

Spectrophotometric catalytic determination of small amounts of rhenium in mineralized rocks and molybdenite  

USGS Publications Warehouse

Rhenium is determined by spectrophotometry of the tellurium sol formed by the reduction of tellurate by stannous chloride under the catalytic influence of rhenium. A detailed investigation of the conditions for high sensitivity and stability at lowest concentration levels of rhenium is presented as well as the behavior of 26 ions. The method is applied to the determination of some tenths of 1 p.p.m. or more of rhenium in a 1-mg. aliquot of mineralized rocks, mixtures of molybdenite and rocks, and molybdenite concentrates. The practical quantity limit of detection is 2 ?? 10-10 gram of rhenium. Samples are decomposed with a mixture of CaO, CaCl2, and MgO. On leaching, most constituents of the sample are precipitated either as calcium salts or hydroxides, except for rhenium and a small amount of molybdenum which pass into the filtrate. Residual molybdenum is removed by extraction with 8-quinolinol in chloroform. Better than 95% recoveries are obtained with two fusions with flux.

Simon, F. O.; Grimaldi, F. S.

1962-01-01

26

Structure-activity studies in E. coli strains on ochratoxin A (OTA) and its analogues implicate a genotoxic free radical and a cytotoxic thiol derivative as reactive metabolites.  

PubMed

Ochratoxin A (OTA), its major metabolite in rodents, ochratoxin alpha, and seven structurally related substances were assayed for SOS DNA repair inducing activity in Escherichia coli strain PQ37. At concentrations of 0.1-4 mM, OTA, chloroxine, 5-chloro-8-quinolinol, 4-chloro-meta-cresol and chloroxylenol induced SOS DNA repair in the absence of an exogenous metabolic activation system. Ochratoxin B, ochratoxin alpha, 5-chlorosalicylic acid and citrinin were inactive, but all except ochratoxin alpha were cytotoxic. Thus, the presence of chlorine at C-5 appears to be one determinant of genotoxicity in these substances. Amino oxyacetic acid, an inhibitor of the cysteine conjugate beta-lyase, decreased the cytotoxicity of OTA but did not alter its genotoxic activity, suggesting the formation of a cytotoxic thiol-containing derivative. The mechanisms by which OTA and some of its active analogues induce SOS DNA repair activity was further investigated in E. coli PQ37 and in three derived strains (PQ300, OG100 and OG400), containing deletions within the oxy R regulon. The response in strain PQ37 was measured in the absence and presence of Trolox C, a water-soluble form of vitamin E. Trolox C completely quenched the genotoxicity of OTA, and the effect was similar in the mutant and wild-type strains. These results implicate an OTA-derived free radical rather than reduced oxygen species as genotoxic intermediate(s) in bacteria. PMID:7513790

Malaveille, C; Brun, G; Bartsch, H

1994-05-01

27

Stabilized liquid membrane device (SLMD) for the passive, integrative sampling of labile metals in water  

USGS Publications Warehouse

A stabilized liquid membrane device (SLMD) is described for potential use as an in situ, passive, integrative sampler for cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in natural waters. The SLMD (patent pending) consists of a 2.5-cm-wide by 15-cm-long strip of low-density polyethylene (LDPE) layflat tubing containing 1 mL of an equal mixture (v/v) of oleic acid (cis-9-octadecenoic acid) and EMO-8Q (7-[4-ethyl-1-methyloctyl]-8-quinolinol). The reagent mixture continuously diffuses to the exterior surface of the LDPE membrane, and provides for sequestration of several divalent metals for up to several weeks. Depending on sampler configuration, concentration factors of several thousand can be realized for these metal ions after just a few days. In addition to in situ deployment, the SLMD may be useful for laboratory determination of labile metal species in grab samples. Methods for minimizing the effects of water flow on the sampling rate are currently under investigation.

Brumbaugh, W. G.; Petty, J. D.; Huckins, J. N.; Manahan, S. E.

2002-01-01

28

The antitumor activity of zinc(II) and copper(II) complexes with 5,7-dihalo-substituted-8-quinolinoline.  

PubMed

[Zn?(ClQ)?(CH?OH)?] (1), [Zn(BrQ)?(H?O)?] (2), [Zn?(ClIQ)?] (3) and [Cu(BrQ)?] (4) (H-ClQ = 5,7-dichloro-8-hydroxylquinoline, H-BrQ = 5,7-dibromo-8-hydroxylquinoline, and H-ClIQ = 5-chloro-7-iodo-8-hydroxylquinoline) were synthesized. Compounds 1-4 showed high anti-proliferative cytotoxicities against BEL-7404, SK-OV-3, NCI-H460 tumor cells, and HL-7702 normal cells in vitro, with IC?? values in the 1.4 nM to 32.13 ?M range. Compounds 2-4 exhibited significantly enhanced cytotoxicity against BEL-7404 cell line, comparing with free 5,7-dihalo-8-quinolinol. Western blotting analysis showed that 2, 3 depleted mutant p53 protein in MDA-MB-231, and compound 2 decreased the ratio of Bcl-2/Bax in NCI-H460 significantly. The binding abilities of 1-4 to DNA were stronger than that of free quinolinol ligand. Intercalation is the probable binding mode for the complexes and free quinolinol ligands with DNA. PMID:24095749

Liu, Yan-Cheng; Wei, Jian-Hua; Chen, Zhen-Feng; Liu, Mei; Gu, Yun-Qiong; Huang, Ke-Bin; Li, Zhu-Quan; Liang, Hong

2013-11-01

29

Hydride-Rhodium(III)-N-Heterocyclic Carbene Catalysts for Vinyl-Selective H/D Exchange: A Structure-Activity Study.  

PubMed

A series of neutral and cationic Rh(III) -hydride and Rh(III) -ethyl complexes bearing a NHC ligand has been synthesized and evaluated as catalyst precursors for H/D exchange of styrene using CD3 OD as a deuterium source. Various ligands have been examined in order to understand how the stereoelectronic properties can modulate the catalytic activity. Most of these complexes proved to be very active and selective in the vinylic H/D exchange, without deuteration at the aromatic positions, displaying very high selectivity toward the ?-positions. In particular, the cationic complex [RhClH(CH3 CN)3 (IPr)]CF3 SO3 showed excellent catalytic activity, reaching the maximum attainable degree of ?-vinylic deuteration in only 20?min. By modulation of the catalyst structure, we obtained improved ?/? selectivity. Thus, the catalyst [RhClH(?(2) -O,N-C9 H6 NO)(SIPr)], bearing an 8-quinolinolate ligand and a bulky and strongly electron-donating SIPr as the NHC, showed total selectivity for the ?-vinylic positions. This systematic study has shown that increased electron density and steric demand at the metal center can improve both the catalytic activity and selectivity. Complexes bearing ligands with very high steric hindrance, however, proved to be inactive. PMID:24895153

Di Giuseppe, Andrea; Castarlenas, Ricardo; Pérez-Torrente, Jesús J; Lahoz, Fernando J; Oro, Luis A

2014-07-01

30

Organic dye lasers with distributed Bragg reflector grating and distributed feedback resonator.  

PubMed

The paper presents polymeric waveguide dye laser with distributed Bragg reflector (DBR) grating or distributed feedback (DFB) resonator. DBR grating and DFB resonator were fabricated on a surface of SU-8 2002 photoresist polymer using interference of laser beams. Polystyrene (PS) and poly(vinyl butyral) (PVB) waveguides dispersed with laser dye of 3-(2-benzothiazolyl)-7-(diethylamino)-coumarin (Coumarin 6) and tris(8-quinolinolate)aluminum (Alq) as a host were used. Single mode of lasing with TE mode was measured from the polymeric waveguide with DBR grating and DFB resonator. Threshold of lasing with DBR grating is lower than that with DFB resonator. For PVB/Alq/Coumarin 6 waveguide, 0.1 mJ cm(-2) pulse(-1) of threshold was measured with DBR grating and 0.3 mJ cm(-2) pulse(-1) with DFB resonator. Slope efficiency between 0.06 and 0.09 % was measured for PS/Alq/Coumarin 6 waveguide and that between 0.07 and 0.15 for PVB /Alq/Coumarin 6 waveguide. PMID:19997411

Tsutsumi, Naoto; Ishibashi, Takashi

2009-11-23

31

Clioquinol induces cytoplasmic clearance of the X-linked inhibitor of apoptosis protein (XIAP): therapeutic indication for prostate cancer.  

PubMed

Clioquinol (5-chloro-7-iodo-8-quinolinol) is a copper ionophore that was used primarily during the 1950-1970s as an oral antimicrobial agent. It has been established that clioquinol displays toxicity towards malignant cells, inducing caspase-dependent apoptosis. In the present study we therefore investigated the effect of clioquinol on the XIAP [X-linked IAP (inhibitor of apoptosis protein)], as one of its primary functions is to hinder caspase activity and suppress apoptotic cell death. Clioquinol treatment caused cytoplasmic XIAP to rapidly relocate to the nucleus in multiple human transformed (hyperplasic and carcinoma) prostate lines. Clioquinol also caused the cytoplasmic clearance of other IAP family members (cIAP1 and cIAP2). Copper, and no other relevant bivalent metal (e.g. zinc or iron), was exclusively required for clioquinol to elicit an effect on XIAP. We further demonstrated that clioquinol selectively targets and rapidly destroys transformed prostate lines without harming primary prostate epithelial cells. The toxicity of clioquinol was copper-dependent, positively correlated with the level of extracellular copper and could be abrogated by using the copper chelator TTM (tetrathiomolybdate). Clioquinol forced the profound accumulation of intracellular copper with ensuing toxicity influenced by key regulators of cellular copper homoeostasis. Taken together, our results provide significant insight into clioquinol toxicity and reveal an exciting therapeutic approach for the treatment of prostate cancer. PMID:21426304

Cater, Michael A; Haupt, Ygal

2011-06-01

32

Highly efficient blue organic light-emitting diodes using quantum well-like multiple emissive layer structure.  

PubMed

In this study, the properties of blue organic light-emitting diodes (OLEDs), employing quantum well-like structure (QWS) that includes four different blue emissive materials of 4,4'-bis(2,2'-diphenylyinyl)-1,1'-biphenyl (DPVBi), 9,10-di(naphth-2-yl)anthracene (ADN), 2-(N,N-diphenyl-amino)-6-[4-(N,N-diphenyl amine)styryl]naphthalene (DPASN), and bis(2-methyl-8-quinolinolate)-4-(phenyl phenolato) aluminum (BAlq), were investigated. Conventional QWS blue OLEDs composed of multiple emissive layers and charge blocking layer with lower highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy level, and devices with triple emissive layers for more significant hole-electron recombination and a wider region for exciton generation were designed. The properties of triple emissive layered blue OLEDs with the structure of indium tin oxide (ITO) /N,N'-diphenyl-N,N'-bis(1-naphthyl-phenyl)-(1,1'-biphenyl)-4,4'-diamine (NPB) (700 ?)/X (100 ?)/BAlq (100 ?)/X (100 ?)/4,7-diphenyl-1,10-phenanthroline (Bphen) (300 ?)/lithium quinolate (Liq) (20 ?)/aluminum (Al) (1,200 ?) (X?=?DPVBi, ADN, DPASN) were examined. HOMO-LUMO energy levels of DPVBi, ADN, DPASN, and BAlq are 2.8 to 5.9, 2.6 to 5.6, 2.3 to 5.2, and 2.9 to 5.9 eV, respectively. The OLEDs with DPASN/BAlq/DPASN QWS with maximum luminous efficiency of 5.32 cd/A was achieved at 3.5 V. PMID:24940170

Yoon, Ju-An; Kim, You-Hyun; Kim, Nam Ho; Yoo, Seung Il; Lee, Sang Youn; Zhu, Fu Rong; Kim, Woo Young

2014-01-01

33

Genotoxicity of ochratoxin A and structurally related compounds in Escherichia coli strains: studies on their mode of action.  

PubMed

Ochratoxin A, ochratoxin alpha (its major metabolite in rodents) and seven structurally related substances were assayed for SOS DNA repair inducing activity in Escherichia coli PQ37 strain. At a concentration range of 0.1-4 mM, ochratoxin A, chloroxine, 5-chloro-8-quinolinol, 4-chloro-meta-cresol and chloroxylenol were found to induce SOS-DNA repair in the absence of an exogenous metabolic activation system. Ochratoxin B, ochratoxin alpha, 5-chlorosalicylic acid and citrinin were inactive, but all except ochratoxin alpha were cytotoxic. Thus, the presence of a chlorine at C-5 in ochratoxin A and in other analogues appears to be one determinant of their genotoxicity. In order to ascertain whether this reactivity involves a bacterial glutathione conjugation reaction, we investigated the modifying effect on the genotoxicity of ochratoxin A of amino oxyacetic acid, an inhibitor of cysteine conjugate beta-lyase. Amino oxyacetic acid decreased the cytotoxicity of ochratoxin A but did not alter its genotoxic activity, suggesting the formation of a cytotoxic thiol-containing derivative. The way in which ochratoxin A and some of its active analogues induce SOS DNA repair activity was further investigated in E. coli PQ37 and in three derived strains (PQ300, OG100 and OG400, containing deletions within the oxy R regulon). The response in PQ37 strain was measured in the absence and presence of Trolox C, a hydrosoluble form of vitamin E. Trolox C completely quenched the genotoxicity of ochratoxin A, which was no greater in mutated than in wild type strains. These results implicate an ochratoxin A-derived free radical rather than reduced oxygen species as genotoxic intermediate(s) in bacteria. PMID:1820340

Malaveille, C; Brun, G; Bartsch, H

1991-01-01

34

Highly efficient blue organic light-emitting diodes using quantum well-like multiple emissive layer structure  

PubMed Central

In this study, the properties of blue organic light-emitting diodes (OLEDs), employing quantum well-like structure (QWS) that includes four different blue emissive materials of 4,4?-bis(2,2?-diphenylyinyl)-1,1?-biphenyl (DPVBi), 9,10-di(naphth-2-yl)anthracene (ADN), 2-(N,N-diphenyl-amino)-6-[4-(N,N-diphenyl amine)styryl]naphthalene (DPASN), and bis(2-methyl-8-quinolinolate)-4-(phenyl phenolato) aluminum (BAlq), were investigated. Conventional QWS blue OLEDs composed of multiple emissive layers and charge blocking layer with lower highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy level, and devices with triple emissive layers for more significant hole-electron recombination and a wider region for exciton generation were designed. The properties of triple emissive layered blue OLEDs with the structure of indium tin oxide (ITO) /N,N?-diphenyl-N,N?-bis(1-naphthyl-phenyl)-(1,1?-biphenyl)-4,4?-diamine (NPB) (700 ?)/X (100 ?)/BAlq (100 ?)/X (100 ?)/4,7-diphenyl-1,10-phenanthroline (Bphen) (300 ?)/lithium quinolate (Liq) (20 ?)/aluminum (Al) (1,200 ?) (X?=?DPVBi, ADN, DPASN) were examined. HOMO-LUMO energy levels of DPVBi, ADN, DPASN, and BAlq are 2.8 to 5.9, 2.6 to 5.6, 2.3 to 5.2, and 2.9 to 5.9 eV, respectively. The OLEDs with DPASN/BAlq/DPASN QWS with maximum luminous efficiency of 5.32 cd/A was achieved at 3.5 V.

2014-01-01

35

Small-Molecule Quinolinol Inhibitor Identified Provides Protection against BoNT/A in Mice  

PubMed Central

Botulinum neurotoxins (BoNTs), etiological agents of the life threatening neuroparalytic disease botulism, are the most toxic substances currently known. The potential for the use as bioweapon makes the development of small-molecule inhibitor against these deadly toxins is a top priority. Currently, there are no approved pharmacological treatments for BoNT intoxication. Although an effective vaccine/immunotherapy is available for immuno-prophylaxis but this cannot reverse the effects of toxin inside neurons. A small-molecule pharmacological intervention, especially one that would be effective against the light chain protease, would be highly desirable. Similarity search was carried out from ChemBridge and NSC libraries to the hit (7-(phenyl(8-quinolinylamino)methyl)-8-quinolinol; NSC 84096) to mine its analogs. Several hits obtained were screened for in silico inhibition using AutoDock 4.1 and 19 new molecules selected based on binding energy and Ki. Among these, eleven quinolinol derivatives potently inhibited in vitro endopeptidase activity of botulinum neurotoxin type A light chain (rBoNT/A-LC) on synaptosomes isolated from rat brain which simulate the in vivo system. Five of these inhibitor molecules exhibited IC50 values ranging from 3.0 nM to 10.0 µM. NSC 84087 is the most potent inhibitor reported so far, found to be a promising lead for therapeutic development, as it exhibits no toxicity, and is able to protect animals from pre and post challenge of botulinum neurotoxin type A (BoNT/A).

Singh, Padma; Singh, Manglesh Kumar; Chaudhary, Dilip; Chauhan, Vinita; Bharadwaj, Pranay; Pandey, Apurva; Upadhyay, Nisha; Dhaked, Ram Kumar

2012-01-01

36

S-shaped decanuclear heterometallic [Ni8Ln2] complexes [Ln(iii) = Gd, Tb, Dy and Ho]: theoretical modeling of the magnetic properties of the gadolinium analogue.  

PubMed

The reaction of 8-quinolinol-2-carboaldoxime (LH2) with Ni(II) and Ln(III) salts afforded the heterometallic decanuclear compounds [Ni8Dy2(?3-OH)2(L)8(LH)2(H2O)6](ClO4)2·16H2O (1), [Ni8Gd2(?3-OH)2(L)8(LH)2(H2O)4(MeOH)2](NO3)2·12H2O (2), [Ni8Ho2(?3-OH)2(L)8(LH)2(H2O)4(MeOH)2](ClO4)2·2MeOH·12H2O (3) and [Ni8Tb2 (?3-OH)2(L)8(LH)2(MeOH)4(OMe)2]·2CH2Cl2·8H2O (4). While compounds 1-3 are dicationic, compound 4 is neutral. These compounds possess an S-shaped architecture and comprise a long chain of metal ions bound to each other. In all the complexes, the eight Ni(II) and two Ln(III) ions of the multimetallic ensemble are hold together by two ?3-OH, eight dianionic (L(2-)) and two monoanionic oxime ligands (LH(-)) whereas compound 4 has two ?3-OH, eight dianionic (L(2-)), two monoanionic oxime ligands (LH(-)) and two terminal methoxy (MeO(-)) ligands. The central portion of the S-shaped molecular wire is made up of an octanuclear Ni(II) ensemble which has at its two ends the Ln(III) caps. Magnetic studies on 1-4 reveal that the magnetic interactions between neighboring metal ions are negligible at room temperature. On the other hand, at lower temperatures in all the compounds anti-ferromagnetic interactions seem to be dominated. Analysis of the magnetic data for the Gd(III) derivative indicates Ni(II)-Ni(II) anti-ferromagnetic interactions and Gd(III)-Ni(II) ferromagnetic interactions at low temperatures. A theoretical density functional study on the magnetic behavior of the Gd(III) derivative suggests that while the weak ferromagnetic interaction between Gd(III) and Ni(II) is in line with the expectation of the magnetic interactions between orthogonal d and f orbitals, antiferromagnetic Ni(II)-Ni(II) interactions are related to the wide Ni-O-Ni angles (?102°) and quasi-planar conformation of the Ni2O2 core. PMID:24876072

Hossain, Sakiat; Das, Sourav; Chakraborty, Amit; Lloret, Francesc; Cano, Joan; Pardo, Emilio; Chandrasekhar, Vadapalli

2014-07-14

37

Clioquinol: review of its mechanisms of action and clinical uses in neurodegenerative disorders.  

PubMed

Clioquinol was produced as a topical antiseptic and marketed as an oral intestinal amebicide in 1934, being used to treat a wide range of intestinal diseases. In the early 1970s, it was withdrawn from the market as an oral agent because of its association with subacute myelo-optic neuropathy (SMON), a syndrome that involves sensory and motor disturbances in the lower limbs and visual changes. The first methods for determining plasma and tissue clioquinol (5-chloro-7-iodo-8-quinolinol) levels were set up in the 1970s and involved HPLC separation with UV detection, these were followed by a more sensitive GC method with electron capture detection and a gaschromatographic-massspectrometric (GC-MS) method. Finally, an HPLC method using electrochemical detection has proved to be as highly sensitive and specific as the GC-MS. In rats, mice, rabbits, and hamsters, clioquinol is rapidily absorbed and undergoes first-pass metabolization to glucuronate and sulfate conjugates; the concentrations of the metabolites are higher than those of free clioquinol. Bioavailabilty versus intraperitoneal dosing is about 12%. Dogs and monkeys form fewer conjugates. In man, single-dose concentrations are dose related, and the drug's half-life is 11-14 h. There is no accumulation, and the drug is much less metabolized to conjugates. Clioquinol acts as a zinc and copper chelator. Metal chelation is a potential therapeutic strategy for Alzheimer's disease (AD) because zinc and copper are involved in the deposition and stabilization of amyloid plaques, and chelating agents can dissolve amyloid deposits in vitro and in vivo. In general, the ability of clioquinol to chelate and redistribute metals plays an important role in diseases characterised by Zn, Cu, Fe dyshomeostasis, such as AD and Parkinson's disease, as it reduces oxidation and the amyloid burden. Zinc chelators may also act as anticancer agents. Animal toxicity studies have revealed species-specific differences in neurotoxic responses that are related to the serum levels of clioquinol and metabolites. This is also true in humans, who form fewer conjugates. The results of studies of Alzheimer patients are conflicting and need further confirmation. The potential therapeutic role of the two main effects of MPACs (the regulation of the distribution of metals and antioxidants) has not yet been fully explored. PMID:21199452

Bareggi, Silvio R; Cornelli, Umberto

2012-01-01