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PubMedDate not supplied

Anticalculus and antiplaque activity of 8-hydroxyquinoline sulfate.

The effect of 8-hydroxyquinoline sulfate on the formation of artificial calculi, rat calculus, and dog plaque plus its ability to remove dog plaque were studied. Several chemically related agents were also evaluated for their anticalculus effects. The most effective anticalculus agent was 8-hydroxyquinoline sulfate. At concentrations of 4 or 5%, swabbed over molar teeth, it was essentially equally effective in retarding the formation of rat calculus. Significant (1% level) reduction occurred with concentration as low as 3% in rats. When used so as to mimic mouthrinse use, 4% 8-hydroxyquinoline sulfate also significantly (5% level) reduced formation of calculus in rats. All rats showed normal behavioral and weight-gain patterns. Visual evaluation of oral tissues in the swabbing tests plus visual and histopathological evaluation of oral tissues in the mouthrinse procedure showed 8-hydroxyquinoline sulfate had no irritating or toxic effects. In dogs, the teeth treated with 4% 8-hydroxyquinoline sulfate nine times during a five-day period had 93.7 to 98.4% less buccal plaque than vehicle-treated teeth. The antiplaque effect was considerable in both canines and fourth premolars. In older dogs, teeth treated with 4% 8-hydroxyquinoline sulfate 15 times during a ten-day period had 33 to 46.1% less plaque than when treated with the vehicle. The effect was considerable on canines but slight on fourth premolars. In older dogs after 24 treatments during a 15-day period, 4% 8-hydroxyquinoline sulfate removed 25 to 57.5% of established plaque whereas the vehicle removed 2.5 to 22.5%. Again, 8-hydroxyquinoline sulfate was more effective on canine buccal plaque. These results show that 8-hydroxyquinoline sulfate is an effective anticalculus and antiplaque agent that is nontoxic to animal oral tissue. The results also indicate that the dog is a suitable animal model for the evaluation of antiplaque agents.

Animals↗

PubMed1976

Hydroxyquinolines inhibit ribonucleic acid-dependent deoxyribonucleic acid polymerase and inactivate Rous sarcoma virus and herpes simplex virus.

8-Hydroxyquinoline and several of its derivatives inactivate the transforming ability of Rous sarcoma virus and inhibit its ribonucleic acid-dependent deoxyribonucleic acid polymerase activity. The copper complex of these metal-binding ligands is as active as the free ligand. The activity of the 8-hydroxyquinolines is approximately 50-fold more effective than another group of metal-binding compounds that we have tested, the thiosemicarbazones. In contrast to the potency of the 8-hydroxyquinolines to inactivate Rous sarcoma virus, no intracellular inhibition of transformation could be demonstrated at a concentration that did not affect the growth and appearance of the cells. Cellular deoxyribonucleic acid synthesis was inhibited to a greater extent than was ribonucleic acid or protein synthesis. The phenomenon of "concentration quenching" was observed with high concentrations of drug, causing less inhibition of deoxyribonucleic acid synthesis than was observed with lower concentrations. Herpes simplex virus type 1 was inactivated also by the 8-hydroxyquinolines and their copper complexes. No intracellular inhibition of plaque formation was observed. Treatment with 8-hydroxyquinoline sulfate had no effect on the resolution of herpetic keratitis in rabbits. Some 8-hydroxyquinolines bind to deoxyribonucleic acid in the presence of copper, a phenomenon that may be important in their antiviral activity.

Animals↗

PubMed1977

The significance of the hairpin counter-current principle in the pathogenesis of toxic kidney lesions. An investigation of the influence of antidiuretic hormone and papaverine on hydroxyquinoline nephropathy of the rat.

The influence of antidiuretic hormone (ADH) and papaverine on hydroxyquinoline-induced nephropathy in rats was tested, using histotopochemistry, enzyme activity measurement and morphometric investigation. Hydroxyquinoline causes a marked increase in renal weight, the development of wedge-shaped foci with severely dilated tubule segments, and a simultaneous reduction in dehydrogenases, alkaline phosphatase, and alpha-naphthyl esterase. Both ADH and papaverine produced a significant inhibition of renal damage. The subjective findings were quantitatively confirmed by measurement of enzyme activity, using the microscope photometer, and by morphometric studies with the Leitz-Classimat (determination on the basis of the alkaline phosphatase reaction) of the surface percentage of brush border in the proximal tubules. A disturbance of the hairpin counter-current system is to be considered as the cause of the renal lesion. This disturbance is caused by hydroxyquinoline-induced impairment of Na+/K+ transport, especially in the thick ascending limb of Henle's loop. Our results show that the hydroxyquinoline nephropathy can be favourably influenced both by stimulation of water re-absorption and possibly also transepithelial Na+ transport (ADH), and by increasing the blood flow of the arteriolae rectae with a resultant lowering of the intratubular urine concentration (papaverine). The dependency of hydroxyquinoline nephropathy on the phylogenetically determined concentration capacity of the kidney, and the effective influencing of the condition by ADH and papaverine indicate the importance of the degree of efficiency of the medullary countercurrent system in the pathogenesis of this renal lesion.

Alkaline Phosphatase↗

PubMed1975

The mechanism of inhibition of ribonucleic acid synthesis by 8-hydroxyquinoline and the antibiotic lomofungin.

RNA synthesis in yeast is rapidly inhibited by 8-hydroxyquinoline and the phenazine antibiotic lomofungin (5-formyl-1-methoxycarbonyl-4,6,8-trihydroxyphenazine). It is shown that lomofungin, like 8-hydroxyquinoline, is a chelating agent for bivalent cations. The mechanism of inhibition of RNA synthesis by lomofungin and 8-hydroxyquinoline was investigated in experiments with isolated Escherichia coli RNA polymerase. The results show that both inhibitors are capable of inhibiting polymerase activity solely by chelating the dissociable cations Mn2+ and Mg2+. Evidence is presented which shows that inhibition may occur in the absence of any direct contact between the RNA polymerase or DNA template and the inhibitor. The possibility that inhibition might also occur by chelation of the Zn2+, which is tightly bound to the polymerase, is discussed: it is concluded that lomofungin or 8-hydroxyquinoline is likely to inhibit the enzyme by removal of Mn2+ and Mg2+ before chelating the Zn2+. On the basis of inhibition by chelation of Mn2+ and Mg2+, explanations are proposed for why lomofungin and 8-hydroxyquinoline inhibit synthesis of ribosomal and polydisperse RNA more than that of 5S RNA and tRNA, and for why protein synthesis is not immediately inhibited in the intact yeast cell.

Chelating Agents↗

PubMed1976

Synthesis and in vitro evaluation of 8-hydroxyquinoline analogs as inhibitors of dental plaque.

A group of 5-substituted 8-hydroxyquinolines with predicted log P values in the 1-4 range has been prepared from either 8-hydroxyquinoline or its appropriate derivative. 5-Formyl-, 5-iodo-, 5-fluoro-, 5-acetyl-, and 5-methoxymethyl-8-hydroxyquinoline in addition to methyl-5(8-hydroxyquinolyl)acetate and ethyl 5-(8-hydroxyquinolyl)acetate displayed greater in vitro antiplaque activity than 8-hydroxyquinoline.

Dental Plaque↗

PubMed1977

Quantitative structure-activity relationships for 5-substituted 8-hydroxyquinolines as inhibitors of dental plaque.

Fourteen 8-hydroxyquinolines were tested for antiplaque activity by measuring their minimum inhibitory concentrations [MIC (M)] against Streptococcus mutans No. 6715. Linear regression analysis was conducted with the MIC (M) values and hydrophobic (log P), electronic (beta, pKaOH, pKaN), and steric [molar refractivity (MR), molecular weight (mol wt)] parameters. The best correlation (r2 = 0.90) was obtained with MR, log P, and beta. The smaller the steric contribution of the 5-substituent, the more active the compound. The parent 8-hydroxyquinoline was the most active. The negative contribution toward activity by 5-substituents larger than hydrogen can be overcome by the positive contributions of groups that are lipophilic and electron withdrawing; for example, the 5-chloro derivative is as active as the parent 8-hydroxyquinolines.

Dental Plaque↗

PubMed1979

Combined cycloheximide and 8-hydroxyquinoline pretreatment for study of plant chromosomes.

The actions of cycloheximide and 8-hydroxyquinoline on dividing cells of root meristems of Zea mays L. have been studied during the development of a new cytological technique for sugar cane (Saccharum) root tips. The determination of mitotic phase indices revealed that combined treatment with cycloheximide (70 ppm) plus 8-hydroxyquinoline (250 ppm) was superior to treatments with either chemical separately. After the combined treatment, the preparations contained nearly ten times more cells in prophase and metaphase that were suitable for chromosome counting than those given a single pretreatment with 8-hydroxyquinoline. This new pretreatment has been developed especially for chromosome studies in tropical grasses with a large number of small chromosomes. However, both chemicals are active in a wide range of plant species.

Chromosomes↗

PubMed1975

Synthesis and in vitro evaluation of 8-hydroxyquinolines as dental plaque inhibitors.

Some 4- and 5-substituted 8-hydroxyquinolines, with predicted log P values in the range of 1.48-2.90, were synthesized by modified Skraup reactions or thermal cyclization. These hydroxyquinolines include the 5-methyl, 4,5-dimethyl, 4-methyl, 5-hydroxy-4-methyl, 5-methoxy, 5-methoxy-4-methyl, 4-hydroxy, 4-chloro, 4-amino, and 5-amino analogs. Partition coefficients, antibacterial activity, and antiplaque activity were determined. Four analogs showed in vitro antiplaque activity. None of the derivatives with ionizable functions was active.

Dental Plaque↗

PubMed1978

8-hydroxyquinoline inhibition of DNA synthesis and intragenic recombination during yeast meiosis.

Complete inhibition of sporulation was observed in two strains of Saccharomyces cerevisiae to which 8-hydroxyquinoline was added at a final concentration of 5 microgram/ml during the initial 4 to 6 h of sporulation. The cells were most sensitive to the inhibitor during 4 to 6 interval beginning at approximately 2 h (T2). Its addition during that interval resulted in 70 to 80% lethality in strain 4579 and about 40% in API at T24. When present from T0 onward, 5 microgram/ml of 8-hydroxyquinoline severely inhibited premeiotic DNA replication and reduced the frequency of intragenic recombination at the ade 2 and leu 2 loci by 70 and 100%, respectively, relative to control cultures which did not have the inhibitor present. During the period when the cells were most sensitive, the incorporation of 14C-leucine into protein and 14C-adenine into RNA was not inhibited nor was the polysome content affected. At 150 microgram/ml of inhibitor, incorporation of labeled precursors into RNA and protein were inhibited and the percentage of active ribosomes was reduced by 35% within 45 min, but neither transcription or translation appeared to be completely inhibited at this concentration of the inhibitor.

Cell Cycle↗

PubMed1975

[Juvenile spongy dystrophy of CNS with necrosis of the medulla. A. complication of hydroxyquinoline therapy (author's transl)].

A girl of 10-5/12 years is described, who had diabetes mellitus from the age of 5 years on and who developed bilateral ptosis, pigment degeneration of the retina and bilateral impairment of hearing at the age of nine years. A few weeks before death she suffered from an acute gastrointestinal infection which was successfully treated by a hydroxyquinoline derivative. In the days following a severe encephalopathy and signs of cardiac involvement appeared. A month later the girl died of bulbar paralysis and acute heart failure. Histology showed remnants of a granulomatous inflammation in the heart, the kidneys, the pancreas and the skeletal muscles. Furthermore there was a widespread spongiosis in the white substance of the brain, with large astrocytes, and partly also in the basal ganglia, the brain stem and the cerebellum. Foci of sudanophilic tissue necrosis resembling Wernicke's Encephalopathy were found in the medulla oblongata and the spinal cord. The peripheral nerves appeared partially demyelinated and showed axonal lesions. This case is classified as a Juvenile Type of so-called Canavan's Disease. It shows some resemblence to the "Progressive Chronic Ophthalmoplegia with Spongiform Encephalopathy described by Daroff, Kearn and Sayre. The possible neurotoxical effects of the hydroxyquinoline therapy are discussed.

Brain↗

PubMed1979

Labeling of human platelets with [111In) 8-hydroxyquinoline.

We have evaluated the factors influencing the labeling of human platelets in the presence of autologous plasma. The labeling efficiency was found to be dependent on a) the time and temperature of incubation, b) the platelet concentration, c) the concentration of citrate ions (in ACD anticoagulant), and d) the concentration of 8-hydroxyquinoline in the suspending medium. Contrary to what was expected, unsaturated transferrin was found not to interfere with the transfer of In-111 from the [111In] 8-hydroxyquinoline complex to the platelets. Based on the findings of this study, a protocol was established by which human platelets can be labeled with In-111 in plasma with a labeling efficiency of 55.5 +/- 9.3 (mean +/- 1 s.d.) percent.

Anticoagulants↗

PubMed1979

Synthesis of quaternary 8-hydroxyquinoline and 8-hydroxyquinaldine-carbamates structurally related to cholinesterase.

The quaternary carbamates were synthesized by reaction of 8-hydroxyquinoline and 8-hydroxyquinaldine with alkylisocyanates, then quaternizing the carbamates produced with alkylhalides, aralkylhalides or sulphate. The UV spectra of the compounds obtained showed lambdamax at 285 nm. The new quaternary carbamates were found to be of high toxicity and parasymapathomimetic activity in white mice.

Animals↗

PubMed1976

The histochemical demonstration of calcium with 8-hydroxyquinoline.

A method for the histochemical demonstration of calcium using 8-hydroxyquinoline was investigated. It was found to give intense, highly selective staining of various pathologic and natural calcifications, and compared favourably with conventional procedures for calcium. Calcium oxalate and calcium pyrophosphate were not stained.

Calcium↗

PubMed1977

Inhibition of amino acyl tRNA synthetase activity by copper complexes of two metal binding ligands. N-Methyl isatin beta-thiosemicarbazone and 8-hydroxyquinoline.

Copper complexes of N-methyl isatin beta-thiosemicarbazone, 1-formyl isoquinoline thiosemicarbazone and thiosemicarbazide inhibit amino acyl tRNA synthetase activity. Copper complexes of 8-hydroxyquinoline and 8-mercaptoquinoline also inhibit. The 1 : 1 ligand-metal complex is significantly more active than the 2 : 1 complex. The free ligand alone and copper sulfate alone have little, if any, effect. These complexes have no effect on the ATP-PPi exchange reaction and do not cause deacylation of amino acyl tRNAs. This indicates that the process inhibited by these complexes is the amino acylation reaction. This is the first report that these copper binding ligands can inhibit enzymatic processes which involve nucleic acids but which are not viral, bacterial or mammalian cell polymerases.

Amino Acyl-tRNA Synthetases↗

PubMed1978

Coordination chemistry of molybdenum and tungsten--VIII. Oxomolybdenum(V) complexes of 8-hydroxyquinoline and relevance of EPR spectra to binding sites in flavoenzymes.

MoOCl3(THF)2 (THF = tetrahydrofuran) reacts with 8-hydroxyquinoline (QH) to form [MoOCl3(QH)2], which contains neutral monodentate ligands, [MoOCl(Q)2], and anionic bidentate ligands, and the dimeric [Mo2O3(Q)4], which contains anionic bidentate ligands and both terminal and bridging oxo donors. In dichloromethane [MoOCl3(QH)2] dissolves to give three species, and epr measurements identify these as unchanged [MoOCl3(QH)2], [MoOCl(Q)2] and a third species characterised by a value of 1.979. No g value of this magnitude has previously been obtained for molybdenum(V) complexes which do not contain sulphur donors, and the significance of epr measurements as an indication of the nature of molybdenum coordination in flavoenzymes must be questioned. These complexes have also been characterised by vibrational and electronic spectral measurements.

Binding Sites↗

PubMed1976

On the mechanism of divalent metal ion chelator induced activation of the 7S nerve growth factor esteropeptidase. Activation by 2,2',2''-terpyridine and by 8-hydroxyquinoline 5-sulfonic acid.

Our previous studies (Pattison, S. E., and Dunn, M. F. (1975), Biochemistry 14, 2733) have shown that the reaction of divalent metal ion chelators with the 140 000 mol wt mouse submaxillary nerve growth factor protein (7S NGF) activates the iota-subunit esteropeptidase activity ca. sevenfold. Ultraviolet-visible spectral studies with the chelator 2,2',2''-terpyridine (terpyridine) and fluorescence emission studies with 8-hydroxyquinoline-5-sulfonic acid (HQSA) in combination with both conventional and rapid-mixing stopped-flow kinetic techniques have been employed in the present study to investigate (a) the mechanism of the chelator-induced activation process, and (b) the identity of the divalent metal ion involved. The spectral studies confirm the presence of stoichiometrically significant amounts of tightly bound zinc ion in native 7S NGF (1-2 g-atoms of An2+/mol of 7S NGF). The kinetic studies show that the reaction of terpyridine with 7S NGF occurs via a two-step process involving first a rapid, apparent second-order step (k1 = 1 x 10(6) M-1 s-1) to form a 7S NGF-Zn2+-chelator monocomplex, then a slow step to form a bis(terpyridine)-Zn(II) complex and activated 7S NGF in an apparent first-order process (kobsd = 0.10 min-1). This rate is, within experimental error, identical with the apparent first-order rate constant for the chelator-induced activation process (monitored by the rate of change in the steady-state rate of hydrolysis of chromophoric substrate, alpha-N-benzoyl-D,L-arginine-p-nitroanilide). Kinetic studies of the reaction of HQSA with native 7S NGF show that, under the same conditions of concentration, the rate of formation of the tris(HQSA)-Zn(II) complex is identical with the rate of the HQSA-induced activation of the 7S NGF esteropeptidase. Thus, these studies unambiguously establish that zinc ion is the metal ion involved in the chelator-induced activation process, and that activation involves removal of zinc ion from native 7S NGF.

Animals↗

PubMed1977

Design, synthesis, and correlation analysis of 7-substituted 4-hydroxyquinoline-3-carboxylic acids as inhibitors of cellular respiration.

Fifteen 7-substituted 4-hydroxyquinoline-3-carboxylic acids have been designed to minimize covariance between the physicochemical substituent parameters: pi, MR, and sigmap. The molecules have been synthesized and evaluated for their ability to inhibit the respiration of Ehrlich ascites cells as a whole cell model and for their ability to inhibit malate dehydrogenase as an intracellular target enzyme model. Correlation analysis indicates that ascites cell inhibition is linearly related to pi and that malate dehydrogenase inhibition is linearly related to MR.

Animals↗

PubMed1976

Catechol O-methyltransferase. 8. Structure-activity relationships for inhibtion by 8-hydroxyquinolines.

A series of 5- and 7-substituted 8-hydroxyquinolines was evaluated as inhibitors of catechol O-methyltransferase (COMT, E.C. 2.1.1.6). The electronic character of the substituents in the 5 position appeared to have only a small effect if any on the inhibitory activity of these compounds. A significant factor which contributes to the inhibitory activity of these compounds appears to be the nature of the 7-substituent. The structure-activity relationship for this series of inhibitors is discussed relative to the nature of the enzymatic binding site.

Animals↗