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PubMed1997

Synthesis and antiplatelet evaluation of alpha-methylene-gamma-butyrolactone bearing 2-methylquinoline and 8-hydroxyquinoline moieties.

In a search for inhibitors of platelet aggregation, some alpha-methylene-gamma-butyrolactones bearing 2-methylquinoline and 8-hydroxyquinoline moieties were synthesized and evaluated for antiplatelet activities against thrombin (Thr)-, arachidonic acid (AA)-, collagen (Col)-, and platelet-activating factor (PAF)-induced aggregation in washed rabbit platelets. With the exception of 2-[[2,3,4,5-tetrahydro-4-methylene-5-oxo-2-(4-phenylphenyl)-2 -furanyl]methoxy]-8-hydroxyquinoline (8f), these alpha-methylene-gamma-butyrolactones completely inhibited the platelet aggregation induced by AA and Col. The 2-methylquinoline derivatives were also active against Thr- and PAF-induced aggregation, while their 8-hydroxyquinoline counterparts were relatively inactive.

4-Butyrolactone↗
PubMedDate not supplied

The complexation of mercury (II) and organomercurial compounds by 8-hydroxyquinoline-bovine serum albumin conjugates.

The complexing properties of conjugates between 8-hydroxyquinoline and bovine serum albumin (Ox-BSA) towards inorganic and organic mercury were studied. Two Ox-BSA conjugates (different substitution ratio) were prepared and their complexing properties were studied. Through the use of titration curves with mercury (II), methylmercury and ethylmercury an evaluation of the complex stoichiometry and stability was obtained, showing that Ox-BSA has good affinity for all investigated mercuric compounds and that the stability increases in the order: Hg (II) < CH3Hg+ < C2H5Hg+, whatever conjugate is considered. Complexes show a stoichiometry of 1:1 between mercury and 8-hydroxyquinoline residues, except with the high substituted conjugate and Hg2+ ion. The skill of the high substituted conjugate to bind inorganic and organic mercury in the presence of NaCl was also studied. Organic mercuric complexes do not show significant modification due to NaCl. Nevertheless, considering inorganic mercury, the number of retained metal ions per protein molecule increases if the NaCl concentration becomes higher than 0.1 M, probably because at high NaCl concentrations 1:1 complexes between mercury and 8-hydroxyquinoline are preferred to 1:2 complexes.

Animals↗
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↗
PubMed1984

Reverse-phase high-performance liquid chromatographic determination of halogenated 8-hydroxyquinoline compounds in pharmaceuticals and bulk drugs.

A reverse-phase high-performance liquid chromatographic (HPLC) method was developed for determining iodochlorhydroxyquin, 5,7-dichloro-8-hydroxyquinoline, and 5,7-diiodo-8-hydroxyquinoline in creams, ointments, shampoos, tablets, and bulk drugs. A column packed with 10-micron phenyl-silica and a mobile phase of 0.001 M NiCl2 in acetonitrile-methanol-water (30:20:50) was used to separate the nickel complexes of the three drugs, with detection at 273 nm. Analysis of creams, ointments, shampoos, and tablets gave results close to the label declarations. Recovery of standard material added to samples was greater than or equal to 98%. Linearity of response was shown over a range of 30-150% of label claim for standards of the three drug substances. Multiple analyses of iodochlorhydroxyquin and diiodohydroxyquinoline bulk drugs showed purities of 99.96 and 98.77% with CV of 1.17 and 0.73%, respectively. The HPLC method offers an alternative to current USP procedures, which lack stability-indicating and specificity characteristics.

Chloroquinolinols↗
PubMed1982

The comparison of 8-hydroxyquinoline, tropolone, and acetylacetone as mediators in the labelling of polymorphonuclear leucocytes with indium-111: a functional study.

Tropolone forms a lipophilic complex with indium-111 which is capable of mediating the labelling of polymorphonuclear leucocytes (PMNs) by this isotope; labelling efficiencies are comparable with the best achieved using 8-hydroxyquinoline and acetylacetone. However, in terms of PMN chemotaxis and phagocytosis, tropolone is significantly less toxic than either of te other ligands. 8-Hydroxyquinoline was found to reduce PMN chemotaxis and phagocytosis to approximately 70% of the control values at a concentration of 20 micro M. Tropolone may prove a superior labelling reagent.

Chemotaxis, Leukocyte↗
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↗
PubMed1988

Synthesis of some 5-azo(4'-substituted benzene-sulphamoyl)-8-hydroxyquinolines with antidotal and antibacterial activities.

5-Azo(4'-substituted benzenesulphamoyl)-8-hydroxyquinolines(III) have been prepared by coupling of the appropriate p-substituted benzenesulphamoyldiazonium acetates with 8-hydroxyquinoline. The corresponding copper chelates(IV) and iron chelates(V) were also prepared in a 1:2 metal to ligand ratio. Structures of III, IV and V were confirmed by some representative UV, IR, and NMR spectrometry in addition to microanalysis. Antidotal activity of four ligands (IIIa, IIId, IIIf, and IIIi) has been evaluated in mice against the toxicity of lead acetate and copper sulphate. Study revealed that compound IIIf elicited significant antidotal activity against lead and copper poisoning, while IIIi was potent only against lead poisoning. Antibacterial activity of compounds III, IV, and V was also determined in comparison to sulphanilamide against Staph. aureus, Bacill. cereus, and Esch. coli. The test compounds showed variable bacteriostatic activities, and some of them (IIIc, IIId, IIIf, Ve, IIIg, and Vi) are more effective than the reference drug, especially against Bacill. cereus.

Animals↗
PubMed1999

A chelating agent possessing cytotoxicity and antimicrobial activity: 7-morpholinomethyl-8-hydroxyquinoline.

7-Morpholinomethyl-8-hydroxyquinoline (MO-8HQ), which like 8-hydroxyquinoline (8HQ) readily forms a chelate, was synthesized and found to possess cytotoxicity and antimicrobial activity. Both 8HQ and MO-8HQ were cytotoxic to human carcinoma cell lines at micromolar concentrations. MO-8HQ also inhibited DNA synthesis of tumor cells at micromolar concentrations, suggesting that MO-8HQ might chelate metals necessary for the enzymatic catalysis of DNA biosynthesis. MO-8HQ was more active against gram positive bacteria than gram negative bacteria and its potency correlated with iron chelation. An "unsaturated" chelate with a MO-8HQ to Fe ratio of 2:1 exhibited greater antibacterial activity than MO-8HQ alone. Among the organisms tested, Micrococcus flavus was most susceptible with a MIC of 3.9 microg/ml. MO-8HQ also exhibited anti-fungal activity at 7-15 microg/ml. MO-8HQ:Fe chelate markedly increased the susceptibility of Escherichia coli to deoxycholate. Addition of Ca2+ or Mg2+ reversed the sensitivity of bacteria to deoxycholate as well as to rifampicin. It is suggested that MO-8HQ exerts its biological activity as a membrane-active agent through metal ion chelation.

Calcium↗
PubMed1987

Detection of specific bacterial enzymes by high contrast metal chelate formation. Part I. 8-Hydroxyquinoline-beta-D-glucoside, an alternative to aesculin in the differentiation of members of the family Enterobacteriaceae.

8-Hydroxyquinoline-beta-D-glucoside has been shown to be a useful alternative substrate for the differentiation of members of the family Enterobacteriaceae based on the presence or absence of beta-glucosidase. In an identification protocol based on multipoint-inoculated plates 8-hydroxyquinoline-beta-D-glucoside when incorporated into an agar based medium supplemented with a ferric salt produced intense black pigmentation localised solely in the immediate vicinity of beta-glucosidase positive organisms. In contrast, using conventional aesculin plates, positive organisms produced a brown ferric-aesculetin complex, the diffusibility of which limited interpretation especially where large numbers of colonies were involved. Almost complete agreement was found when 1964 routine 'coliform' organisms were tested by both methods. The method described allows use of a 36 place 'minipin' inoculator without any danger of 'nearest neighbour' interference and constitutes a cost-effective method suitable for either manual or automatic reading.

Chemical Phenomena↗
PubMed2003

Kinetic study of the riboflavin-sensitised photooxygenation of two hydroxyquinolines of biological interest.

4-Hydroxyquinoline (4-OHQ) and 8-hydroxyquinoline (8-OHQ), two compounds of interest because of their bioactivity and their structural relation with bioactive products, are effectively photooxygenated when irradiated with visible light in the presence of riboflavin (Rf) (vitamin B2) in solution in air-saturated water-methanol (9:1). Rf behaves as a dye-sensitiser, since both quinolines are transparent to visible light. 8-OHQ degrades about five times faster than 4-OHQ. Kinetic data obtained through time-resolved and stationary detection of Rf-electronically excited states indicate that a superoxide radical anion-mediated mechanism exclusively operates for 4-OHQ, whereas singlet molecular oxygen--mainly--plus superoxide radical anion is the species that reacts with 8-OHQ. The sensitiser Rf, which is known to photodegrade under visible-light aerobic irradiation, is regenerated in the presence of any of the quinolines through an electron transfer process that produces superoxide radical anion. The overall picture indicates that both quinolines act as sacrificial scavengers of the photogenerated oxygen species, thus preventing the photodegradation of Rf.

Hydroxyquinolines↗
PubMed2000

Spectral behavior and pH dependence of N-hexadecyl-5-iminomethyl-8-hydroxyquinoline.

A new kind of amphiphile derived from 8-hydroxyquinoline, N-hexadecyl-5-iminomethyl-8-hydroxyquinoline (HIHQ) was synthesized and characterized by different physical methods. The influence of pH value on UV-vis absorption, fluorescence spectra were investigated and the surface pressure area isotherms were recorded under different pH subphase. The linear response range between the emission intensity and the concentration of HIHQ was 1-4 x 10(-6) mol L(-1). The strongest emission of HIHQ about 460 nm was obtained at pH 8.2 and the acid-base equilibrium of HIHQ in monolayer and solution was also discussed.

Hydrogen-Ion Concentration↗
PubMed2000

Use of 8-hydroxyquinoline-beta-D-glucuronide for presumptive identification of Shiga toxin-producing Escherichia coli O157.

8-hydroxyquinoline-beta-D-glucuronide (HQG) was used to improve the presumptive identification of Shiga toxin-producing Escherichia coli O157 (STEC O157) on sorbitol MacConkey agars (SMAC). Advantages of HQG are (i) that it is less expensive than 5-bromo-4-chloro-3-indoxyl-glucuronide; (ii) that it is visible in normal daylight and (iii) that it does not diffuse into the agar like 4-methylumbelliferryl-beta-D-glucuronide (MUG). Sixteen STEC O157 isolates, 91 bovine mastitis-associated E. coli isolates and 222 faecal E. coli isolates from apparently healthy cattle were used in this study. 4-methylumbelliferryl-beta-D-glucuronide detected beta-glucuronidase activity in more isolates than HQG (P < 0.05). On SMAC with HQG, cefixime and tellurite all STEC O157 isolates grew as cream-coloured colonies (100% sensitivity), whereas all non-STEC O157 E. coli except one grew either not at all or as purple or black colonies (99.7% specificity). No difference was found between faecal and mastitis isolates for the proportion of isolates that hydrolysed HQG or MUG or fermented sorbitol. However, significantly more mastitis isolates were able to grow in the presence of the cefixime-tellurite supplement. 8-Hydroxyquinoline-beta-D-glucuronide is a useful substrate for the identification of STEC O157 on SMAC.

Animals↗
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↗
PubMed1991

Microbial metabolism of quinoline and related compounds. IX. Degradation of 6-hydroxyquinoline and quinoline by Pseudomonas diminuta 31/1 Fa1 and Bacillus circulans 31/2 A1.

Two strains, using 6-hydroxyquinoline as sole source of energy, carbon and nitrogen, have been isolated. These bacteria, designated 31/1 Fa1 and 31/2 A1, are also able to degrade quinoline. According to their physiological properties strain 31/1 Fa1 has been identified as Pseudomonas diminuta and strain 31/2 A1 as Bacillus circulans. 6-Hydroxy-2-oxo-1,2-dihydroquinoline was found as intermediate in the degradation of 6-hydroxyquinoline and quinoline. 2-Oxo-1,2-dihydroquinoline was the first metabolite in the degradation of quinoline.

Bacillus↗
PubMed2002

A rapid spectrophotometric method for the determination of molybdenum in industrial, environmental, biological and soil samples using 5,7-dibromo-8-hydroxyquinoline.

A very simple, ultra-sensitive and highly selective non-extractive spectrophotometric method for the determination of trace amount of molybdenum(VI) using 5,7-dibromo-8-hydroxyquinoline (DBHQ) has been developed. 5,7-Dibromo-8-hydroxyquinoline reacts in a slightly acidic solution (0.05 - 1.0 M H2SO4) with molybdenum(VI) to give a deep greenish-yellow chelate which has an absorption maximum at 401 nm. The reaction is instantaneous and the absorbance remains stable for over 24 h. The average molar absorption coefficient and Sandell's sensitivity were found to be 4.13 x 10(3) L mol(-1) cm(-1) and 7 ng cm(-2) of molybdenum(VI), respectively. Linear calibration graphs were obtained for 0.1 - 50 microg mL(-1) of molybdenum(VI). The stoichiometric composition of the chelate is 1:3 (Mo:DBHQ). A large excess of over 50 cations, anions and some common complexing agents (e.g. EDTA, oxalate, citrate, phosphate, thiourea, SCN-) do not interfere with the determination. The method was successfully used in the determination of molybdenum in several Standard Reference Materials (alloys, steels and waters) as well as in some environmental waters (inland and surface), biological samples (human blood and urine), soil samples, solution containing both molybdenum(V) and molybdenum(VI) and complex synthetic mixtures. The method has high precision and accuracy (S = +/-0.01 for 0.5 microg mL(-1)).

Alloys↗
PubMed1986

Studies on lipoxygenase inhibitors. II. KF8940 (2-n-heptyl-4-hydroxyquinoline-N-oxide), a potent and selective inhibitor of 5-lipoxygenase, produced by Pseudomonas methanica.

Pseudomonas methanica KY4634 was found to produce 5-lipoxygenase inhibitor designated KF8940, MY12-62a and MY12-62c. The inhibitors were purified by solvent extraction, silica gel column chromatography, reversed-phase low pressure liquid chromatography and crystallization. The chemical structures of KF8940, MY12-62a and MY12-62c were determined to be 2-n-heptyl-4-hydroxyquinoline-N-oxide, 2-n-heptyl-4-hydroxyquinoline and 3-n-heptyl-3-hydroxy-1,2,3,4-tetrahydroquinoline-2,4-dione, respectively, on the basis of their physico-chemical properties. Among them, KF8940 was the most potent inhibitor. The compound inhibited 5-lipoxygenase of rat basophilic leukemia cells in a dose-dependent manner and the half maximal inhibitory concentration (IC50) was 1.5 X 10(-7) M. At this concentration, KF8940 did not inhibit bovine platelet 12-lipoxygenase and cyclooxygenase, and the IC50 values for these enzyme were 3.5 X 10(-5) M and 1.7 X 10(-4) M, respectively. The results indicated that KF8940 is a potent and selective inhibitor of 5-lipoxygenase. The IC50 value of MY12-62c for 5-lipoxygenase was 1.9 X 10(-5) M and that of MY12-62a was 1.9 X 10(-5) M.

Arachidonate Lipoxygenases↗
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↗
PubMed1982

[On the different release kinetics of water-soluble and lipid-soluble forms of hydroxyquinoline in oleogel ointment bases (author's transl)].

Studies using the model according to Horsch and Kögel showed that the release kinetics of the suspended water-soluble (but not lipid-soluble) drugs hydroxyquinoline sulphate and hydroxy-quinoline sulphate--potassium sulphate from oleogels is of a zero order. Differences in drug dispersity do not affect the release rates. Oleogels containing the lipid-soluble hydroxyquinoline base yielded undersaturated solution ointments, the release kinetics of which can be stated by a semilogarithmic relationship. There exists a linear correlation between the release rates and the product of the lipid solubility of the drug and the reciprocal apparent distribution coefficient.

Chemistry, Pharmaceutical↗