PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Azo Compounds”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 1,099 records · Page 61Linked to original sources
PubMed1975

A novel diazonium-sulfhydryl reaction in the inactivation of yeast alcohol dehydrogenase by diazotized 3-aminopyridine adenine dinucleotide.

Diazotized 3-aminopyridine adenine dinucleotide has been found to modify four sulfhydryl groups per molecule of enzyme during the complete inactivation of yeast alcohol dehydrogenase. The reaction of sulfhydryl groups was indicated by titration studies with 5,5-dithiobis(2-nitrobenzoic acid) as well as isolation and quantitation of the cysteinyl derivative released by acid hydrolysis of the modified enzyme. The cysteinyl derivative was identified as S-(3-pyridyl)cysteine. Authentic S-(3-pyridyl)cystein was synthesized and structurally characterized for these studies. Diazonium-sulfhydryl reactions were demonstrated for a number of diazonium derivatives with cysteine, homocysteine, glutathione, and mercaptoethanol at 0-4 degrees and neutral pH. Second order rate constants were determined in reactions of these sulfhydryl compounds with diazotized 1-methyl-3-aminopyridinium chloride, diazotized 3-aminopyridine adenine dinucleotide, and diazotized 3-aminopyridine adenine dinucleotide phosphate.

Alcohol Oxidoreductases↗
PubMed1975

Tumor induction by carcinogenic agents in aquarium fish.

The effects of nine carcinogens on 1,220 guppies [Poecilea reticulata (Lebistes reticulatus)] and 40 zebra fish (Danio rerio) were studied. Multiple exposure techniques included skin application, im and ip injections, feeding, implantation in pellets, and dissolving of the compound in the aquarium water. 7-12-Dimethylbenz[a]anthracene, 3-methylcholanthrene, and benzidine produced no tumors in the fish. N-2-Fluorenylacetamide, omicron-aminoazotoluene, 4-dimethylaminoazobenzene, diethylnitrosamine, and dimethylnitrosamine induced tumors in the livers of some of the fish. These neoplasms included cholangiomas, hepatoadenomas, cholangiocarcinomas, and hepatocellular cancers. Nitrosomorpholine caused not only hepatic tumors in guppies and zebra fish but also intestinal adenocarcinomas and poorly differentiated connective-tissue lesions in the abdominal cavities of zebra fish. Experimental induction of tumors in aquarium fish offers wide possibilities for comparative cancer research. Fish are a suitable model for the testing of compounds for carcinogenic activity and for the screening of environmental carcinogens.

2-Acetylaminofluorene↗
PubMedDate not supplied

In vitro activity of mitochondrial ATP synthetase inhibitors against Plasmodium falciparum.

The mitochondrion appears to be essential for the growth of asexual, intraerythrocytic stages of Plasmodium falciparum and may thus be a suitable chemotherapeutic target. The in vitro activity of almitrine, a mitochondrial ATP synthetase inhibitor used for the treatment of hypoxemia, was compared with other mitochondrial inhibitors against chloroquine-susceptible and chloroquine-resistant P. falciparum using an isotopic semimicro drug susceptibility assay. The 50% inhibitory concentration (IC50) values of almitrine (range: 2.6-19.8 microM) were within similar range of values of other mitochondrial ATP synthetase inhibitors and doxycycline, a mitochondrial protein synthesis inhibitor. Almitrine was equally active against chloroquine-susceptible and chloroquine-resistant parasites. Drug combination studies showed no interaction between chloroquine and almitrine. Our results suggest that almitrine, a clinically safe drug, may represent a lead compound with a specific target against the mitochondrial ATP synthetase which may be useful for antimalarial chemotherapy.

Almitrine↗
PubMed1979

Synthesis of the glucuronic acid conjugate of methylazoxymethanol.

The glucuronic acid conjugate of methylazoxymethanol was synthesized by oxidizing the primary alcohol of the glucose moiety of cycasin (methylazoxymethanol-beta-D-glycopyranoside) to a carboxylic acid. The oxidation was carried out by bubbling oxygen gas through a cycasin solution in the presence of a platinum-on-carbon catalyst. A band at 1715 cm-1, not present in the cycasin infrared spectrum, appeared in the spectrum of the oxidized cycasin product, establishing the presence of a carboxylic acid group. The oxidation product is methylazoxymethanol-beta-D-glucosiduronic acid because, when hydrolyzed with Escherichia coli beta-glucuronidase, it produced methylazoxymethanol and glucuronic acid and also indicated retention of the beta-linkage of cycasin. Varying quantities of the synthesized methylazoxymethanol-glucosiduronic acid, injected into Wistar rats of both sexes and of varying weights, were not acutely toxic. The compound was mutagenic to Salmonella typhimurium when preincubated with E. coli beta-glucuronidase, but not when preincubated with bovine liver glucuronidase.

Animals↗
PubMed1980

Synthesis of some newer formazans and tetrazolium salts and their effect on Ranikhet disease virus and the vaccinia virus.

Synthesis and biological evaluation of a series of formazans and their corresponding tetrazolium salts are described. Several 1,3,5-trisubstituted formazans were prepared by condensing 4-acetoxy-3-methoxybenzaldehydephenylhydrazone and 2,4-dinitrophenylhydrazone of 2-benzimidazolecarboxaldehyde, with an appropriate phenyldiazonium salt. The formazans derived from 4-acetoxy-3-methoxybenzaldehydephenylhydrazone were further oxidized to their corresponding cyclization products, 2,3,5-trisubstituted tetrazolium salts. Oxidation of 1-aryl-3-(2'-benzimidazolyl)-5-(5-(2',4'-dinitrophenyl) formazans to their corresponding tetrazolium salt did not meet with success. Both the highly coloured formazans and water-soluble tetrazolium salts were screened for their antiviral, activity against vaccinia virus and Ranikhet disease virus in a stationary culture of chorioallantoic membrane of chick embryo. Two of the compounds were found to exhibit significant activity (87% and 83%) against the Ranikhet disease virus. However no activity against vaccinia virus could be observed.

Antiviral Agents↗
PubMed1994

The assessment of the HO. scavenging action of therapeutic agents.

A new method is reported for the assessment of the HO. scavenging action of therapeutic agents. It is based on the photolysis of zinc oxide and has a detection limit of 3.3%. The scavenging order of the compounds tested was penicillamine > rentiapril > ascorbic acid > cysteine > glutathione > thiomalic acid > N-acetylcysteine > myocrysin > methionine. None were as effective as DMSO. It is argued that these compounds can have an in vivo protective effect where HO. is produced from oxidant producing cells, thus limiting radical induced damage.

Azo Compounds↗
PubMed2006

Synthesis and studies on some new fluorine containing triazolothiadiazines as possible antibacterial, antifungal and anticancer agents.

Synthesis of a series of 7-arylidene-6-(2,4-dichlorophenyl)-3-aryloxymethyl/anilinomethyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines (3) by the condensation of 3-aryl-1-(2,4-dichloro-5-fluorophenyl)-2-bromo-propen-1-one (1) and 4-amino-5-mercapto-3-aryloxymethyl/anilinomethyl-1,2,4-triazoles (2) is described. The newly synthesized compounds were characterized by elemental analysis IR, 1H NMR and mass spectral data. These compounds were tested for their antimicrobial activities against Escherichia coli, Staphylococcus aureus (Smith), Psuedomonas aeruginosa (Gessard), Bacillus subtilis and Candida albicans. Some of the newly synthesized compounds were also screened for their anticancer activity. Among them compounds 3m, 3o, 3q showed in vitro anticancer activity.

Anti-Bacterial Agents↗
PubMed2000

1,2-Diphenyl-2-(phenyldiazenyl)-2-tosylethanone, an example of a fungicide containing a sulfonyl group.

The molecule of the title compound, C(27)H(22)N(2)O(3)S, adopts an irregular propeller shape with the tetrahedral C1 atom pivotal. The alpha-azophenyl and alpha-phenyl moieties are approximately coplanar. Electrostatic attraction of the oppositely charged atoms generates several short intramolecular contacts involving the sulfonyl, azo and carbonyl groups. Characteristic bond-length distribution of the central part of the molecule indicates that the Coulombic charge transfer is supplemented by hyperconjugation involving donation of electron density from the azo moiety towards the sulfonyl and carbonyl groups.

Azo Compounds↗
PubMed1990

TCDD inhibits the support of B-cell development by the bursa of Fabricius.

The toxic effects produced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and its congeners include inhibition of lymphoid development. We have previously found an inhibition of B-cell development in the bursa of Fabricius of chick embryos treated with TCDD congeners in ovo. In the present study, the bursae of ten-day-old chick embryos were removed and cultured on filter paper for 24 hr in media with or without TCDD or 3,3',4,4'-tetrachlorazoxybenzene (TCAOB). Following culture, the bursae were transplanted onto the chorioallantoic membrane (CAM) of ten-day-old eggs of the same strain or of a strain expressing a different B-cell surface alloantigen. After 5 days on the CAM the number of B-cells was determined or the grafts were sectioned for subsequent immunohistochemistry. Results were as follows: 1) A lower number of lymphoid cells (dose dependent) was observed in the TCDD-treated transplants amounting to 40-50% of that in the controls at 10(-9) M TCDD. Higher concentrations of TCDD compromised survival of the grafts. A single concentration of TCAOB (10(-8) M) was tested, resulting in a lymphoid cell number of 60% of that of the controls. 2) The bursal epithelium showed relatively normal development even in cases where B-cell development was affected. 3) Lymphoid cells in the grafted bursae originated from the embryo of the host egg. These findings suggest that the TCDD congeners had a direct effect on the bursa of Fabricius, leading to an inhibition of lymphoid development. It is likely that the microenvironment is affected by these compounds, thus resulting in a decrease in the attraction of stem cells and/or in the capacity to induce proliferation of the colonizing cells.

Animals↗
PubMed2006

Novel tiO2 nanocatalysts for wastewater purification: tapping energy from the sun.

Water treatment using TiO2 semiconductor as a durable heterogeneous photocatalyst has been the focus of environmentalists in recent years. Currently, we developed an inexpensive and highly efficient approach for synthesizing nitrogen-doped TiO2 with lower band-gap energy that can respond to visible light. Doping on the molecular scale led to an enhanced nitrogen concentration of up to 21.8%. Reflectance measurements showed the synthesized N-doped TiO2 nanoparticles are catalytically active with the absorbance that extends into the visible region up to 600 nm. The water purification potential of this new class of compound was evaluated by studying the photodegradation of Acid Orange 7 (AO7) and E. coli. Experiments were conducted to compare the photocatalytic activities of N-doped TiO2 nanocatalysts and commercially available Degussa P25 power under identical solar light exposure. N-doped TiO2 demonstrated superior photocatalytic activities in both chemical compound degradation and bactericidal reactions. The result of this study shows the potential of applying new generations of catalyst for wastewater purification and disinfection.

Azo Compounds↗
PubMed2003

Monitoring the influence of toxic compounds on microbial denitrifying biofilm processes.

Microelectrode measurements were conducted to obtain nitrate, pH and redox potential profiles within anoxic denitrifying biofilms. The influence of a toxic organic compound (acid orange 7) on biofilm microprofiles was also monitored using microelectrodes. The data provide evidence that the denitrifying biofilms were stratified into an anoxic layer and an anaerobic layer. The anaerobic zone might provide a niche for the biodegradation of recalcitrant organic compounds in biofilms. It was found that acid orange 7 and its biodegradation byproducts had only a slight impact on biofilm nitrate, pH and redox potential profiles.

Azo Compounds↗
PubMedDate not supplied

Phase I and pharmacokinetic studies of DON.

DON, a glutamine antagonist, was administered iv to 26 patients with advanced cancer either once every 3 wks or daily for 3 days every 3 wks to determine toxicity and to look for evidence of therapeutic effect. Total doses ranged from 150 to 600 mg/m2. The single-day schedule produced intolerable nausea and vomiting and no evidence of cytotoxicity at 450-550 mg/m2 given over 10 mins or over 4 hrs. On the 3-day schedule, patients had tolerable gastrointestinal toxic effects at total doses up to 480 mg/m2 given in three equally divided doses by 10-min infusion. This dose also produced cytotoxic activity manifested as transient mild leukopenia and, rarely, thrombocytopenia. No objective responses were seen. Analysis of the plasma elimination of DON demonstrated dose-dependent pharmacokinetic behavior. The parent compound was not detectable in the urine of any patient, indicating extensive metabolism of the drug.

Azo Compounds↗
PubMed1977

Thromboxane synthetase inhibitors as pharmacological tools: differential biochemical and biological effects on platelet suspensions.

The comparative effects of three so called "thromboxane-synthetase-inhibitors" (imidazole, N-0164, and U-51605) on arachidonate metabolism and on platelet aggregation were studied. All three compounds blocked platelet microsomal thromboxane synthesis from prostaglandin endoperoxides without affecting platelet adenyl cyclase. Imidazole, blocked thromboxane synthesis in intact platelets either from arachidonic acid or PGH2, without affecting aggregation. U-51605 simultaneously inhibited thromboxane synthesis and platelet suspension aggregation. N-0164 inhibited aggregation probably at extracellular sites, at concentrations that did not alter arachidonate or PGH2 metabolism. High concentrations of N-0164 simultaneously inhibited PG cyclo-oxygenase and thromboxane synthetase. The lack of specificity of these compounds requires that other actions of these compound must be considered when they are used as pharmacological tools to inhibit thromboxane synthetase.

Arachidonic Acids↗
PubMed1988

The distribution of DMBA and its dihydrodiols in tissues of control and Sudan-III-treated Long-Evans rats after the injection (i.v.) in vivo of a leukaemogenic dose of the hydrocarbon.

7,12-Dimethylbenz[a]anthracene (DMBA) is a potent leukaemogenic agent in Long-Evans rats when it is administered i.v. in vivo. The prior oral administration of Sudan III [1(p-phenylazo-phenylazo)-2-naphthol] protects animals from the leukaemogenic effects of this compound. Sudan-III-treatment resulted in an increased rate of removal of DMBA from the livers and blood of treated animals and resulted in a reduced level of accumulation of the hydrocarbon in its presumed target tissue, the bone marrow. The regio-selective hepatic metabolism of DMBA was altered in Sudan-III-treated animals, thus only trans-3,4-dihydro-3,4-dihydroxy-DMBA was recovered from the livers of control animals whereas only trans-8,9-dihydro-8,9-dihydroxy-DMBA was recovered from the livers of Sudan-III-treated animals. The distribution of DMBA dihydrodiols in the blood and in the bone marrow was found to reflect the findings in the liver. DMBA, when incubated with rat bone marrow cells in vitro, was metabolized to probable phenolic compounds but no evidence whatsoever was found for dihydrodiol formation in these cells. Taken together these results are consistent with a model in which Sudan-III-induced alterations in the regio-selective hepatic metabolism of DMBA are responsible for the protection against leukaemogenesis afforded by the administration of that compound. The probable mechanism of protection is the induction in liver of a cytochrome P450, probably P450c.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1980

Active intestinal transport of methyl red isomers.

Transport across the wall of rat jejunum of two isomers of methyl red has been studied. These isomers, meta-methyl red (MMR) and para-methyl red (PMR), are absorbed against a concentration gradient. Uptake consists of three components: rapid adsorption on to the mucosa, a steady uptake proportional to lumen concentration and a reflux which increases exponentially to a limiting value. A substantial part of the uptake is stored in the mucosa, and some of it is metabolized to colourless derivatives. If methyl red is washed out of the lumen after the mucosa has been loaded, there is some reflux into the lumen, but most of the stored methyl red passses into the secretion. The rate of this transport on to the serosal surface is not noticeably diminished until the adverse concentration gradient exceeds 13-14:1. Once the methyl red has been washed out of the lumen there is no further metabolism of methyl red to colourless derivatives. Shifting the lumen pH from 7.4 to 6.4 whilst keeping the tissue fluid pH constant increases the rate of uptake from the lumen by a factor of only 1.68 although the concentration of unionized methyl red is increased approximately 10-fold. It seems that at pH 7.4 about 90% of the uptake is of the ionized form, and that at pH 6.4 this percentage falls to 50. It is concluded that the methyl reds form fresh examples of foreign organic compounds which can be transported actively by the small intestine and that they can be taken up from the lumen into the mucosa in both ionized and unionized states.

Animals↗