Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Aminophenols”

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

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

At least 109 records · Page 6Linked to original sources
PubMed1987

Reciprocal modifying effects of isomeric forms of aminophenol on induction of neoplastic lesions in rat liver and kidney initiated by N-ethyl-N-hydroxyethylnitrosamine.

The effects of four isomeric forms of aminophenols, ortho-, meta-, para-aminophenol and acetaminophen (o-, m-, p-AP and AAP, respectively) on liver and kidney carcinogenesis initiated by N-ethyl-N-hydroxyethylnitrosamine (EHEN) were tested. Rats were given 0.1% EHEN (in their drinking water for 2 weeks) and then diet containing these compounds at concentrations of 0.8% for 49 weeks. Administration of o-AP and AAP significantly decreased the number and area of preneoplastic foci staining immunohistochemically for glutathione S-transferase placental type (GST-P) per unit area of liver section as compared with the values for rats given EHEN alone. o-AP and AAP also significantly decreased the incidence of hepatocellular carcinoma. In contrast, p-AP and AAP significantly increased quantitative values for kidney preneoplastic lesions and renal cell adenoma. It is suggested that the cytotoxic effects of these chemicals preferentially suppressed the proliferation of preneoplastic liver cells, but stimulated the mitotic activity of preneoplastic tubular lesions in the kidney.

Acetaminophen↗
PubMed2001

Genetic and structural organization of the aminophenol catabolic operon and its implication for evolutionary process.

The aminophenol (AP) catabolic operon in Pseudomonas putida HS12 mineralizing nitrobenzene was found to contain all the enzymes responsible for the conversion of AP to pyruvate and acetyl coenzyme A via extradiol meta cleavage of 2-aminophenol. The sequence and functional analyses of the corresponding genes of the operon revealed that the AP catabolic operon consists of one regulatory gene, nbzR, and the following nine structural genes, nbzJCaCbDGFEIH, which encode catabolic enzymes. The NbzR protein, which is divergently transcribed with respect to the structural genes, possesses a leucine zipper motif and a MarR homologous domain. It was also found that NbzR functions as a repressor for the AP catabolic operon through binding to the promoter region of the gene cluster in its dimeric form. A comparative study of the AP catabolic operon with other meta cleavage operons led us to suggest that the regulatory unit (nbzR) was derived from the MarR family and that the structural unit (nbzJCaCbDGFEIH) has evolved from the ancestral meta cleavage gene cluster. It is also proposed that these two functional units assembled through a modular type gene transfer and then have evolved divergently to acquire specialized substrate specificities (NbzCaCb and NbzD) and catalytic function (NbzE), resulting in the creation of the AP catabolic operon. The evolutionary process of the AP operon suggests how bacteria have efficiently acquired genetic diversity and expanded their metabolic capabilities by modular type gene transfer.

Amino Acid Sequence↗
PubMed2005

Constitutive synthesis of enzymes involved in 2-aminophenol metabolism and inducible synthesis of enzymes involved in benzoate, p-hydroxybenzoate, and protocatechuate metabolism in Pseudomonas sp. strain AP-3.

Pseudomonas sp. strain AP-3 grows on benzoate, p-hydroxybenzoate, protocatechuate, and 2-aminophenol as sole carbon and energy source. This strain converted benzoate and p-hydroxybenzoate to catechol and protocatechuate respectively, which were metabolized via the ortho-cleavage pathway. The enzymes responsible for these reactions were shown to be inducible. In contrast, strain AP-3 constitutively expresses the enzymes involved in the metabolism of 2-aminophenol.

Aminophenols↗
PubMed2007

Improvement in selectivity and storage stability of a choline biosensor fabricated from poly(aniline-co-o-aminophenol).

A choline biosensor was fabricated by using electrochemical doping to immobilize choline oxidase in poly(aniline-co-o-aminophenol) film that exhibits a good electric activity over a wide pH range. Using cyclic voltammetry, impedance measurement and scanning electron microscopy characterized the poly(aniline-co-o-aminophenol) film doped with choline oxidase. The amperometric detection of choline is based on the oxidation of the H2O2 enzymatically produced on the choline biosensor. The choline biosensor has a lower potential dependence. Thus, its operational potential was controlled at a low potential of 0.40 V (vs.SCE). The response current of the choline biosensor increases with increasing temperature from 277.1 to 308.1 K. An apparent activation energy of 30.8 kJ mol(-1) was obtained. The choline biosensor has a wide linear response range from 1x10(-7) to 1x10(-4) M choline with a correlation coefficient of 0.9999 and has a high sensitivity of 127 microA cm(-2), at 0.40 V and pH 8.0. The response time of the biosensor is 15-25 s, depending on the applied potentials. An apparent Michaelis constant and an optimum pH for the immobilized enzyme are 1.8 mM choline and 8.4, respectively, which are very close to those of choline oxidase in solution. The effect of selected organic compounds on the response of the choline biosensor was studied. Together, these findings show that the choline biosensor exhibits a better selectivity to interfering species and a better storage stability.

Alcohol Oxidoreductases↗
PubMedDate not supplied

Effects of phenylhydroxylamine and aminophenols in Japanese quail in vivo.

1. The effects of phenylhydroxylamine, and o- and p-aminophenol were studied in the Japanese quail. 2. Symptoms normally observed in aniline-treated birds were seen in quail after phenylhydroxylamine dosage at > 10 mg/kg. Aminophenols (up to 50 mg/kg) did not give these symptoms. 3. Injection of phenylhydroxylamine (50 mg/kg) resulted in formation of 70% ferrihaemoglobin after 5 min, following which a rapid reduction of ferrihaemoglobin was observed. 4. Phenylhydroxylamine reached highest blood concn. of 0.2 mumol/ml after 5 min. Phenylhydroxylamine was reduced to aniline within 5 min. 5. The effects of aniline in vivo are most probably due to O2 shortage caused by ferrihaemoglobin formation.

Aminophenols↗
PubMedDate not supplied

Spontaneous formation of immunogenic conjugates by ortho- and para-aminophenol.

Ortho-aminophenol (OAP) and para-aminophenol (PAP) react readily with proteins at alkaline pH giving rise to conjugates capable to induce hapten specific antibodies in rabbits. PAP and OAP immunological systems do not cross react with each other, but both anti-PAP and anti-OAP serum give intense cross passive hemagglutination reactions with hydroquinone and pyrocatechin conjugates prepared by the same procedure. PAP immunological system does not cross react with various systems of the "para" group in which the conjugates were prepared by diazotization. PAP proved unable to induce formation of specific antibodies when inoculated in Freund adjuvant into rabbits and both PAP and OAP were unable to sensitize erythrocytes by incubation at alkaline pH. The findings are discussed in the light of data from literature showing that some drugs with amino aromatic structure are transformed in the body into compounds with PAP or OAP structure which might be able to form immunogenic conjugates with autologous proteins in vivo.

Aminophenols↗
PubMed1989

Characterization of the interaction between prostacyclin and human serum albumin using a fluorescent analogue, 2,6-dichloro-4-aminophenol iloprost.

We synthesized a fluorescent probe, 2,6-dichloro-4-aminophenol iloprost or dichlorohydroxyphenylamide of iloprost (DCHPA-iloprost) by reacting the stable prostacyclin analog, iloprost (ZK 35 374), with 2,6-dichloro-4-aminophenol with a yield of 60%. This probe exhibited an optical spectrum which overlapped with the emission spectrum of the sole tryptophan of human serum albumin (HSA). Energy transfer from the tryptophan residue to the phenol moiety of DCHPA-iloprost was observed. We utilized this donor-quenching phenomenon to quantitate the binding stoichiometry and affinity as well as the association rate of DCHPA-iloprost binding to HSA. As DCHPA-iloprost showed similar binding characteristics similar to those of iloprost and prostacyclin and competed with iloprost for HSA binding sites, we used DCHPA-iloprost as a probe to locate the binding domain of prostacyclin (PGI2) in HSA. The distance between the tryptophan indole and the phenol group of DCHPA-iloprost was estimated to be 15-18 A. Because iloprost binding to HSA was competitive with warfarin and not with free fatty acid, we propose that PGI2 binds to the 'domain 2' of HSA was competitive with warfarin and not with free fatty acid, we propose that PGI2 binds to the 'domain 2' of HSA molecules. A possible molecular mechanism by which HSA reduces the chemical degradation of PGI2 and stabilizes its activity could be derived from this model.

Binding Sites↗
PubMed2004

Tetradentate bis(o-iminobenzosemiquinonate(1-)) pi radical ligands and their o-aminophenolate(1-) derivatives in complexes of nickel(II), palladium(II), and copper(II).

The coordination chemistries of the potential tetradentate ligands N,N'-bis(3,5-di-tert-butyl-2-hydroxyphenyl)ethylenediamine, H4[L1], the unsaturated analogue glyoxal-bis(2-hydroxy-3,5-di-tert-butylanil), H2[L2], and N,N'-bis(2-hydroxy-3,5-di-tert-butylphenyl)-2,2-dimethylpropylenediamine, H4[L3], have been investigated with nickel(II), palladium(II), and copper(II). The complexes prepared and characterized are [Ni(II)(H3L1)2] (1), [Ni(II)(HL2)2].5/8CH2Cl2 (2), [Ni(II)(L3**)] (3), [Pd(II)(L3**)][Pd(II)(H2L3) (4), and [Cu(II)(H2O)(L4)] (5), where (L4)2- is the oxidized diimine form of (L3)4- and (L3**)2- is the bis(o-iminosemiquinonate) diradical form of (L3)4-. The structures of compounds 1-5 have been determined by single crystal X-ray crystallography. In complexes 1 and 2, the ligands (H3L1)- and (HL2)- are tridentate and the nickel ions are in an octahedral ligand environment. The oxidation level of the ligands is that of an aromatic o-aminophenol. 1 and 2 are paramagnetic (mu(eff) approximately 3.2 mu(B) at 300 K), indicating an S = 1 ground state. The diamagnetic, square planar, four-coordinate complexes 3 and [Pd(II)(L3**)] in 4 each contain two antiferromagnetically coupled o-iminobenzosemiquinonate(1-) pi radicals. Diamagnetic [Pd(II)(H2L3)] in 4 forms an eclipsed dimer via four N-H.O hydrogen bonding contacts which yields a nonbonding Pd.Pd contact of 3.0846(4) A. Complex 5 contains a five-coordinate Cu(II) ion and two o-aminophenolate(1-) halves in (L4)2-. The electrochemistries of complexes 3 and 4a ([Pd(II)(L3**)] of 4) have been investigated, and the EPR spectra of the monocations and -anions are reported.

Journal Article↗
PubMed1999

Preparation of 2-aminomuconate from 2-aminophenol by coupled enzymatic dioxygenation and dehydrogenation reactions.

2-Aminomuconate is an intermediate in the oxidative metabolism of tryptophan in mammals. The compound is not commercially available, and studies of its metabolism have been prevented by the lack of a chemical synthesis and the instability of the molecule. We report here the formation of 2-aminomuconate from 2-aminophenol by the coupled action of 2-aminophenol 1,6-dioxygenase and 2-aminomuconic semialdehyde dehydrogenase from Pseudomonas pseudoalcaligenes JS45, and isolation of the product by anion exchange chromatography. The overall procedure was completed within 3 h with a yield of 62%. The availability of the dicarboxyl alpha-amino acid provides the basis for investigation of the physiological function of 2-aminomuconate in the neuropathologically significant oxidative metabolism of tryptophan.

Journal Article↗
PubMed2002

A novel meta-cleavage dioxygenase that cleaves a carboxyl-group-substituted 2-aminophenol. Purification and characterization of 4-amino-3-hydroxybenzoate 2,3-dioxygenase from Bordetella sp. strain 10d.

A bacterial strain that grew on 4-amino-3-hydroxybenzoic acid was isolated from farm soil. The isolate, strain 10d, was identified as a species of Bordetella. Cell extracts of Bordetella sp. strain 10d grown on 4-amino-3-hydroxybenzoic acid contained an enzyme that cleaved this substrate. The enzyme was purified to homogeneity with a 110-fold increase in specific activity. The purified enzyme was characterized as a meta-cleavage dioxygenase that catalyzed the ring fission between C2 and C3 of 4-amino-3-hydroxybenzoic acid, with the consumption of 1 mol of O2 per mol of substrate. The enzyme was therefore designated as 4-amino-3-hydroxybenzoate 2,3-dioxygenase. The molecular mass of the native enzyme was 40 kDa based on gel filtration; the enzyme is composed of two identical 21-kDa subunits according to SDS/PAGE. The enzyme showed a high dioxygenase activity only for 4-amino-3-hydroxybenzoic acid. The Km and Vmax values for this substrate were 35 micro m and 12 micro mol.min-1.(mg protein)-1, respectively. Of the 2-aminophenols tested, only 4-aminoresorcinol and 6-amino-m-cresol inhibited the enzyme. The enzyme reported here differs from previously reported extradiol dioxygenases, including 2-aminophenol 1,6-dioxygenase, in molecular mass, subunit structure and catalytic properties.

Amino Acid Sequence↗
PubMed2005

A novel o-aminophenol oxidase responsible for formation of the phenoxazinone chromophore of grixazone.

Grixazone contains a phenoxazinone chromophore and is a secondary metabolite produced by Streptomyces griseus. In the grixazone biosynthesis gene cluster, griF (encoding a tyrosinase homolog) and griE (encoding a protein similar to copper chaperons for tyrosinases) are encoded. An expression study of GriE and GriF in Escherichia coli showed that GriE activated GriF by transferring copper ions to GriF, as has been observed for a Streptomyces melanogenesis system in which the MelC1 copper chaperon transfers copper ions to MelC2 tyrosinase. In contrast with tyrosinases, GriF showed no monophenolase activity, although it oxidized various o-aminophenols as preferable substrates rather than catechol-type substrates. Deletion of the griEF locus on the chromosome resulted in accumulation of 3-amino-4-hydroxybenzaldehyde (3,4-AHBAL) and its acetylated compound, 3-acetylamino-4-hydroxybenzaldehyde. GriF oxidized 3,4-AHBAL to yield an o-quinone imine derivative, which was then non-enzymatically coupled with another molecule of the o-quinone imine to form a phenoxazinone. The coexistence of N-acetylcysteine in the in vitro oxidation of 3,4-AH-BAL by GriF resulted in the formation of grixazone A, suggesting that the -SH group of N-acetylcysteine is conjugated to the o-quinone imine formed from 3,4-AHBAL and that the conjugate is presumably coupled with another molecule of the o-quinone imine. GriF is thus a novel o-aminophenol oxidase that is responsible for the formation of the phenoxazinone chromophore in the grixazone biosynthetic pathway.

Acetylcysteine↗
PubMed1976

Colorimetry of carbohydrates with m-aminophenol, and its proposed use in measurement of serum amylase activity.

In the reaction of m-aminophenol with carbohydrates in a thiourea/acetic acid reagent, addition of borate suppresses chromogen formation for hexoses and pentoses, and enhances it for disaccharides. All reaction products absorb maximally at 520 nm. The relatively greater intensity of the m-aminophenol/maltose reaction product was used in a saccharogenic method for amylase, with low blank readings. This method is compared with two dye/starch procedures.

Amylases↗
PubMed1996

Induction of chromosomal aberrations by 2,4-dichloro-6-aminophenol in cultured V79 cells.

2,4-Dichloro-6-aminophenol (DCAP) is a major metabolite of the herbicide 2,4-dichloro-6-nitrophenol ammonium (DCNPA). In our previous studies this metabolite, but not the parent compound, was found to induce sister chromatid exchanges (SCEs) and micronucleus (MN) formation in Chinese hamster lung fibroblasts (V79 cells). Further studies were carried out to determine whether DCAP can also induce structural chromosomal aberrations (CAs) in cultured V79 cells. The assay was performed under three different treatment conditions: 1) 3 h treatment followed by 17 h post-treatment incubation. 2) 12 h treatment, and 3) 20 h treatment with multiple sampling times. Results showed that CAs were induced by DCAP in V79 cells. The aberrations were mainly chromatid types (gaps, breaks, and deletions), triradials, quadriradials, and complex rearrangements. However, induction of CAs appears to be dependent on the treatment condition. The 3 h treatment following a 17 h post-treatment incubation gave rise to 24% aberrant cells (excluding gaps) and a total of 44 aberrations per 100 metaphases, while the 12 h treatment only gave a borderline response and the 20 h treatment did not yield a significant increase of CAs at any concentration tested. It seems that a short-term treatment with higher concentrations is a better treatment protocol for genotoxicity studies of certain cytotoxic chemicals such as DCAP. Results of this study further indicate that the herbicide DCNPA is potentially hazardous to the exposed population.

Aminophenols↗
PubMed2004

Quantitative determination of p-aminosalicylic acid and its degradation product m-aminophenol in pellets by ion-pair high-performance liquid chromatography applying the monolithic Chromolith Speedrod RP-18e column.

An ion-pair high performance liquid chromatographic method was developed for the simultaneous determination of p-aminosalicylic acid (PAS) and its degradation product m-aminophenol (MAP) in a newly developed multiparticular drug delivery system. Owing to the concentration differences of PAS and MAP, acetanilide and sulfanilic acid were used as internal standards, respectively. The separation was performed on a Chromolith SpeedROD RP-18e column, a new packing material consisting of monolithic rods of highly porous silica. The mobile phase composition was of 20 mm phosphate buffer, 20 mm tetrabutylammonium hydrogen sulphate and 16% (v/v) methanol adjusted to pH 6.8, at a flow-rate of 1.0 mL/min, resulting in a run-time of about 6 min. Detection was by UV at 233 nm. The method was validated and proved to be useful for stability testing of the new dosage form. Separation efficiency was compared between the new packing material Chromolith SpeedROD RP-18e and the conventional reversed-phase cartridge LiChroCART 125-4 (5 microm). A robustness test was carried out on both columns and different separation parameters (retention, resolution, run time, temperature) were determined.

Aminophenols↗
PubMed1995

Genotoxic effects of p-aminophenol in Chinese hamster ovary and mouse lymphoma cells: results of a multiple endpoint test.

p-Aminophenol (PAP), a metabolite of aniline and acetaminophen, has been reported to be mutagenic in the L5178Y mouse lymphoma assay, but not in the CHO/HGPRT assay. In the present study, the effects of PAP in these two cells lines were examined to determine if the difference in activity is related to an intrinsic difference in the cell lines. CHO and L5178Y tk +/- mouse lymphoma cells were treated with PAP for 4 hr and assayed for 3 genetic endpoints: gene mutation at the HGPRT or TK locus, respectively; chromosomal aberrations at approximately 20 hr after initiation of treatment; and single-strand DNA breaks as detected by the single cell electrophoresis assay immediately after treatment. All treatments were conducted in the absence of S9. There was a dose-related, significant increase in TFT-resistant mouse lymphoma cells at dose levels that reduced survival to < or = 50% of concurrent controls. In CHO cells, however, there was no increase in thioguanine-resistant cells at dose levels that reduced cell survival to < 20%. These results are consistent with published reports on PAP. While the CHO cells were slightly more resistant to the toxic effects of PAP, the dose levels used in the two cell lines did not differ by more than 2-fold. At equivalent survival levels, PAP induced a significant (up to 20% aberrant cells) number of aberrations, primarily complex rearrangements, in both cell lines. In the single cell electrophoresis assay, there was a reproducible dose-related increase in cells with single-strand DNA breaks with both the L5178Y cells and the CHO cells. The induction of single-strand breaks and chromosome aberrations by PAP suggests that, mechanistically, PAP produces similar genetic damage in both CHO and L5178Y cell lines, but intrinsic differences between assay systems are responsible for the divergent gene mutation results.

Aminophenols↗
PubMed2004

p-Aminophenol-induced hepatotoxicity in hamsters: role of glutathione.

p-Aminophenol (PAP) is a widely used industrial chemical and a known nephrotoxin. Recently, it was found to also cause hepatotoxicity and glutathione (GSH) depletion in mice. The exact mechanism of liver toxicity is not known. The aims of this study were to determine whether PAP can cause acute hepatotoxicity in hamsters and to further investigate the role of GSH in PAP-induced toxicity. PAP was administered ip to hamsters in doses of 200-800 mg/kg. Liver damage at 24 h after PAP administration was assessed by elevations in plasma enzyme activities and histopathologic examination. GSH and cysteine (Cys) levels in liver at 4 h were determined by HPLC. PAP decreased hepatic GSH concentration to 8% and Cys to 30% of vehicle control values. It increased plasma glutamic pyruvic transaminase (GPT) activity by 47-fold and sorbitol dehydrogenase (SDH) activity by 113-fold. PAP also caused severe centrilobular hepatocellular necrosis. 2(RS)-n-Propylthiazolidine-4(R)-carboxylic acid (PTCA), a Cys precursor, attenuated the PAP-induced decreases in hepatic sulfhydryl levels; GSH and Cys were 39% and 78% of vehicle controls, respectively. PTCA also attenuated the PAP-induced elevations in plasma enzyme activities and hepatic necrosis. It was concluded that PAP hepatotoxicity is associated with depletion of hepatic GSH and can be prevented by PTCA.

Alanine Transaminase↗
PubMed1987

Determination of aspirin by pre-column transacetylation reaction of 3-aminophenol and reversed-phase high-performance liquid chromatography: simultaneous determination of aspirin, acetaminophen, and caffeine.

The accuracy of the measurement of aspirin by high-performance liquid chromatography (HPLC) is reduced by its hydrolysis into salicylic and acetic acids during sample preparation. The ready and quantitative transacetylation of 3-aminophenol by aspirin, giving 3-hydroxyacetanilide (which is stable), has been utilized as a pre-column reaction for the determination of aspirin either alone or in the presence of acetaminophen and caffeine by reversed-phase HPLC.

Acetaminophen↗