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PubMed1990

Chiral amines derived from 2-arylpropionic acids: novel reagents for the liquid chromatographic (LC) fluorescence assay of optically active carboxylic acid xenobiotics.

For the enantiospecific analysis of optically active carboxylic acids, the availability of readily detectable coupling components is desirable, but highly fluorescent chiral amines are rare. From activated enantiomers of fluorescent 2-arylpropionic acids fluorescent chiral amines were synthesized via Curtius degradation, i.e., under formation of the acyl azide, the isocyanate, and finally, the amine. The formation of isocyanates and of amine hydrochlorides led to an inversion of the direction of rotation of polarized light. Amines derived from R- and S-flunoxaprofen, R- and S-naproxen, and R/S-benoxaprofen were characterized. The amines were found to be applicable for the chiral separation of carboxylic acids (such as 2-arylpropionic acids) as diastereomeric derivatives via high-performance liquid-chromatographic (normal and reversed-phase) and thin-layer chromatographic techniques.

Amines↗
PubMed1997

Aromatic amines and cancer.

Epidemiological evidence on the relation between aromatic amines and cancer risk is reviewed. In particular, cancer risk in humans resulting from exposure to aromatic amines from occupational sources and tobacco smoking is assessed with reference to ecologic, cohort, and case-control studies. Seven arylamines have been classified by the International Agency for Research on Cancer: benzidine-based dyes and MOCA (4,4'-methylene bis 2-choloroaniline) were considered 'probably' carcinogenic, Group 2A, because of a high level of evidence in experimental animals; two occupational chemicals (2-naphthylamine and benzidine), one drug (Chlornaphazine), and two manufacturing processes (manufacture of auramine and magenta) were included in Group 1 on the basis of 'sufficient' evidence of carcinogenicity in humans. Occupational exposures to aromatic amines explain up to 25 percent of bladder cancers in some areas of Western countries; these estimates might be higher in limited areas of developing countries. Aromatic amines contaminate the ambient air as a component of environmental tobacco smoke. There is increasing evidence that the excess of bladder cancer in smokers is attributable to aromatic amines rather than to other contaminants of tobacco smoke such as polycyclic aromatic hydrocarbons (PAH). A modulating role in the risk of bladder cancer associated with exposure to aromatic amines is played by metabolic polymorphisms, such as the N-acetyltransferase genotype, raising important social and ethical issues. The consistent observation of a difference between men and women in bladder cancer risk, after allowing for known risk factors, suggests consideration of gender-related biological determinants for future investigation.

2-Naphthylamine↗
PubMed1994

Biogenic amines in table olives. Analysis by high-performance liquid chromatography.

Biogenic amines in fermented vegetables have scarcely been studied. Available data show that in table olives and fermented cucumbers their presence is rare and any determinations made have been restricted mainly to histamine. However, some microorganisms, especially those related to spoilage, found in the fermentation brines of such products may have amino acid decarboxylase activity and give rise to biogenic amines by unusual processes. A method for the simultaneous determination of eight biogenic amines (tryptamine, beta-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine) has been developed to study their occurrence in fermented vegetables in more detail. The method consists of extraction of the amines from olive paste with 5% m/v trichloracetic acid and successive transfers into water-saturated n-BuOH and 0.1 mol l-1 HCl. An aliquot of this mixture is dried and derivatized with dansyl chloride. The dansyl derivatives are then analysed by high-performance liquid chromatography. Special emphasis has been given to optimization of the n-BuOH and 0.1 mol l-1 HCl extractions and to the derivatization conditions. By applying this method to the analysis of spoilt olives, the presence of some biogenic amines has been demonstrated. Thus a new method for monitoring the presence of biogenic amines during the fermentation of olives and for detecting anomalous fermentations is envisaged.

Biogenic Amines↗
PubMed1974

Simulation of biogenic amine metabolism in the brain.

The metabolism of a number of biogenic amines has been simulated by using data obtained from studies of the individual enzymes from pig brain. It is shown that beta-hydroxylated amines such as noradrenaline and octopamine are metabolized primarily to the alcoholic metabolite whereas amines lacking this group [e.g. dopamine (3,4-dihydroxyphenethylamine) and 5-hydroxytryptamine] are metabolized at low concentrations to give the corresponding acid. Increase in the amine concentration results in an increase in the proportion of the alcoholic metabolite formed and this may in part account for the effects of the drug reserpine on amine metabolism. The effects of disulfiram (Antabuse) and ethanol (acting through its metabolite acetaldehyde) on amine metabolism may be understood in terms of this simulated model. It is shown that drugs that affect this system also cause alterations in the steady-state concentrations of the intermediate aldehydes and the possible implications of this are discussed.

Animals↗
PubMed1999

Cancer chemopreventive mechanisms of tea against heterocyclic amine mutagens from cooked meat.

Cooking meat and fish under normal conditions produces heterocyclic amine mutagens, several of which have been shown to induce colon tumors in experimental animals. In our search for natural dietary components that might protect against these mutagens, it was found that green tea and black tea inhibit the formation of heterocyclic amine-induced colonic aberrant crypt foci (ACF) in the rat. Since ACF are considered to be putative preneoplastic lesions, we examined the inhibitory mechanisms of tea against the heterocyclic amines. In the initial studies using the Salmonella mutagenicity assay, green tea and black tea inhibited according to the concentration of tea leaves during brewing and the time of brewing; a 2-3-min brew of 5% green tea (w/v) was sufficient for >90% antimutagenic activity. N-hydroxylated heterocyclic amines, which are direct-acting mutagens in Salmonella, were inhibited by complete tea beverage and by individual components of tea, such as epigallocatechin-3-gallate (EGCG). Inhibition did not involve enhanced mutagen degradation, and EGCG and other catechins complexed only weakly with the mutagens, suggesting electrophile scavenging as an alternative mechanism. Enzymes that contribute to the metabolic activation of heterocyclic amines, namely microsomal NADPH-cytochrome P450 reductase and N, O-acetyltransferase, were inhibited by tea in vitro. Studies in vivo established that tea also induces cytochromes P450 and Phase II enzymes in a manner consistent with the rapid metabolism and excretion of heterocyclic amines. Collectively, the results indicate that tea possesses anticarcinogenic activity in the colon, and this most likely involves multiple inhibitory mechanisms.

Amines↗
PubMed1986

Short-circuiting the visual cycle with retinotoxic aromatic amines.

The retinotoxic drug 1,5-di-(p-aminophenoxy)pentane inhibits the accumulation of all 11-cis-retinoids in the eye and can deplete preformed stores of them. It is shown here that these effects are not specific to 1,5-di-(p-aminophenoxy)pentane but are shared generally by primary aromatic amines containing a hydrophobic tail. Furthermore, certain clinically used drugs, such as the anti-inflammatory drug phenacetin, can be metabolized to produce these retinotoxic amines. It is likely that hydrophobic aromatic amines will in general be retinotoxic, and drugs based on these structures need to be reassessed in this light. It is proposed here that these amines function by catalyzing the isomerization of 11-cis-retinal thermodynamically downhill to form its all-trans congener. This mechanism accounts for the lack of structural specificity observed with these compounds and is supported by experimental evidence presented here. Schiff bases formed between 11-cis-retinal and a relevant aromatic amine in phosphatidylcholine-based liposomes lead to the formation of the all-trans isomer, at rates approximately equal to 15 times faster than the rate of 11-cis-retinal isomerization by itself in these liposomes and 10(2)-10(3) times faster than the rate of isomerization of this molecule in n-heptane. The rates of the amine-catalyzed isomerization are fast enough to account for their in vivo effect.

Amines↗
PubMed1997

Effect of metal on 2,4,5-trihydroxyphenylalanine (topa) quinone biogenesis in the Hansenula polymorpha copper amine oxidase.

Previous studies of wild-type and mutant forms of a recombinant copper amine oxidase from Hansenula polymorpha, expressed in Saccharomyces cerevisiae, have indicated a self-processing mechanism for 2,4,5-trihydroxyphenylalanine (topa) quinone biogenesis involving the active site copper (Cai, D., and Klinman, J. P. (1994) J. Biol. Chem. 269, 32039-32042). In contrast to prokaryotic copper amine oxidases, however, it has not been possible to initiate topa quinone formation by the addition of exogenous copper to precursor H. polymorpha amine oxidase lacking copper. Metal analysis of copper-depleted wild-type enzyme reveals 0.2-0.3 mol copper, together with 0.6 mol zinc. Despite changes in the zinc and copper levels in growth media, the level of zinc in purified enzyme remains fairly constant. Further, we have been unable to displace protein-bound zinc by exogenously added copper. The H. polymorpha amine oxidase gene was subsequently expressed in Escherichia coli and found to be almost completely free of copper and zinc. In vitro reconstitution of this apoprotein confirms that zinc binds to H. polymorpha amine oxidase and prevents reconstitution with copper. By contrast, addition of copper first to apoprotein leads to formation of topa quinone and stable activity in the presence of added zinc. These findings indicate efficient binding of either zinc or copper to a site that undergoes little or no exchange. The data confirm that topa quinone biogenesis in the H. polymorpha system is catalyzed by copper and occurs in the absence of added factors. We conclude that the mechanisms of cofactor biogenesis in pro- and eukaryotic systems are likely to be similar or identical. The results described herein imply different pathways for the in vivo assembly of heterologously expressed amine oxidases in S. cerevisiae and E. coli.

Amine Oxidase (Copper-Containing)↗
PubMed2000

Influence of various parameters on the browning of potassium sorbate in the presence of amines.

Potassium sorbate can undergo oxidation to form carbonyl moieties and cause browning. This investigation studied the fate of the compounds produced by auto-oxidation of potassium sorbate and measured the browning in the presence of amines. Experimental plans in which four factors were combined (temperature, oxygen, amine and light) led to the observation that the interaction between oxygen and high temperature (75 degrees C) favoured browning, independently of the presence of amine. At 4 degrees C, the amine seemed to cause a decrease in the proportion of carbonyl-containing compounds which would appear to participate in carbonyl-amine reactions. At 75 degrees C, the amine forms adducts with the potassium sorbate. In parallel, high temperature favours auto-oxidation reactions that produce carbonyls. GC/MS and NMR analysis of the reaction products of potassium sorbate/amine mixtures led to the identification of cyclic products.

Amines↗
PubMed1987

A simple test to monitor aromatic amine clearance in occupational workers.

A simple, quick and sensitive procedure is described to monitor urinary clearance of aromatic amines in industrial workers. Estimation is based on the measurement of coloured Schiff's bases developed with 4-dimethylaminocinnamaldehyde-organic acid reagent. Extraction of amines in water saturated butanol ensured 89-97% recovery from biological samples with a coefficient of variation of less than 8%. Regression analyses of the absorbance-concentration curves with different aromatic amines showed excellent correlation coefficient and a high molar absorptivity with the lowest detection limits ranging between 0.05-0.12 microgram ml-1. The proposed reagent has additional use as a spray reagent to detect amine spots on chromatograms. Low final acidity ensures estimates of free amines without causing hydrolysis of conjugated amines.

Amines↗
PubMed1990

Mutagenicity in V79 cells does not correlate with carcinogenity in small rodents for 12 aromatic amines.

The aim of this investigation was to study the correlation between carcinogenicity in small rodents and mutagenic potency of aromatic amines, as measured by the induction of 6-thioguanine resistance in V79 Chinese hamster cells. It has been previously shown that the carcinogenic potency of these compounds is not correlated to their ability to induce DNA breakage, SCEs, or point mutations in bacteria, but a correlation exists with autoradiographic DNA repair test (in primary hepatocyte cultures). Twelve aromatic amines were tested and the rat liver S9 fraction was routinely incorporated in the mutation assay; mouse liver and hamster liver S9 fractions were also used as metabolizing systems. The comparison of the ranks of mutagenic and oncogenic potencies by means of the Spearman test shows no correlation between carcinogenicity and V79 cell mutagenicity of the tested aromatic amines. There was a generally low mutagenicity seen for aromatic amines in V79 cells. In some cases this could be attributed to an insufficient metabolic activation by rat S9. For example, benzidine, which was inactive when assayed in the presence of rat S9, became mutagenic when in the presence of mouse S9. On the other hand, hamster S9, which has been shown to be the best activating system for 2-acetylaminofluorene in the Ames test, did not activate this compound in V79 cells. Inadequate metabolic activation of the standard system (rat S9) used in this work could explain the low mutagenicity and the lack of correlation observed between mutagenicity and carcinogenicity. A second possibility is that point mutation is not the essential end point for the initiating activity of aromatic amines during the carcinogenic process. A third possibility is that the activity of some aromatic amines is not restricted to the initiation step in carcinogenesis. Chronic treatments with the sublethal doses often result in significant promoting activities, which could mask efficiently the initiating potential of the same chemicals.

Amines↗
PubMed2005

Improved approach for proteochemometrics modeling: application to organic compound--amine G protein-coupled receptor interactions.

MOTIVATION: Proteochemometrics is a novel technology for the analysis of interactions of series of proteins with series of ligands. We have here customized it for analysis of large datasets and evaluated it for the modeling of the interaction of psychoactive organic amines with all the five known families of amine G protein-coupled receptors (GPCRs). RESULTS: The model exploited data for the binding of 22 compounds to 31 amine GPCRs, correlating chemical descriptions and cross-descriptions of compounds and receptors to binding affinity using a novel strategy. A highly valid model (q2 = 0.76) was obtained which was further validated by external predictions using data for 10 other entirely independent compounds, yielding the high q2ext = 0.67. Interpretation of the model reveals molecular interactions that govern psychoactive organic amines overall affinity for amine GPCRs, as well as their selectivity for particular amine GPCRs. The new modeling procedure allows us to obtain fully interpretable proteochemometrics models using essentially unlimited number of ligand and protein descriptors.

Amines↗
PubMed1995

Coupling in the absence of tertiary amines. V. Removal of the 2-nitrobenzenesulfenyl (NPS) group with 1-hydroxybenzotriazole in the presence of aniline or N-methylaniline.

In a search for conditions of acidolytic removal of amine protecting groups leading to salts of the deblocked amine that can be acylated without addition of a tertiary amine, cleavage of the 2-nitrobenzenesulfenyl (Nps) group with hydroxybenzotriazole (HOBt) in 2,2,2-trifluoroethanol was attempted. The Nps group was smoothly removed, but the resulting salt of the amine component could not be acylated unless deprotonated with a tertiary base. A rationale is now proposed for this unsatisfactory outcome of the cleavage reaction and for the concomitant surprising reduction of HOBt to benzotriazole. Based on the proposed mechanism, a new approach was designed for the removal of the Nps group. It was cleaved with HOBt in the presence of weakly basic nucleophiles such as aniline, N-methylaniline or 8-aminoquinoline. The protecting group was transferred smoothly to the amino group of the nucleophilic acceptor leaving the deblocked amine component in the form of its HOBt salt. This was then readily acylated without addition of a tertiary amine.

Amines↗
PubMed1995

Detection and identification of amines in bacterial vaginosis.

For the purpose of determining an objective indicator of bacterial vaginosis (BV), we tried to detect and to identify amines in the vaginal fluid of patients by using the dansyl method (to detect amine in a solution of water). Bacteria isolated from these patients were also analyzed. 1) In BV (n: 32) 7 kinds of amines were detected; and the positive rate of detection of the dansyl method was 90.6%. No specific bacteria was found in BV. 2) The positive rate was 80.0% for the patients with trichomonas vaginitis (n: 5). 3) The positive rate of detection was 20.0% in the candida group (n: 5), and 28.6% in the control group (n: 14). Those amines detected in other than BV-related vaginitis are presumed not to vaporize. For purposes of diagnosis, it would be better to detect vaporized amines instead of detecting amines dissolved in vaginal fluid.

Amines↗
PubMed1997

Amine precursor uptake and decarboxylation: significance for processing of the rat gastrin precursor.

1. Conversion of prohormone precursors to smaller active products occurs in secretory granules, which also have the capacity to concentrate biogenic amines. We have examined how processing of the gastrin precursor, progastrin, in rat antral mucosa is influenced by modulation of the biogenic amine content of secretory granules. 2. Newly synthesized progastrin-derived peptides in rat antral mucosa were labelled in vitro with 35SO4(2-) using a pulse-chase protocol and detected after immunoprecipitation by HPLC with on-line liquid scintillation counting. Secretory granule morphology was examined by electron microscopy. The effects of experimentally manipulating secretory granule pH and amine content were examined. 3. The dopamine precursor L-beta-3,4-dihydroxyphenylalanine (L-DOPA) inhibited cleavage of 35S-labelled thirty-four amino acid amidated gastrin, i.e. [35S]G34, and of [35S]G34 with COOH-terminal glycine, i.e. [35S]G34-Gly, at a pair of lysine residues, but did not influence cleavage of progastrin at pairs of arginine residues. The effect of L-DOPA was reversed by reserpine, which inhibits the amine-proton exchangers VMAT1 and VMAT2, and by carbidopa, which inhibits aromatic L-amino acid decarboxylase. 4. Treatments that raise intragranular pH, e.g. the weak base chloroquine, the ionophore monensin and the vacuolar proton pump inhibitor bafilomycin A1, had similar effects to L-DOPA. 5. Electron microscopical studies showed that the electron-dense aggregrates in gastrin cell secretory granules were lost after inhibition of the vacuolar proton pump. Treatment with L-DOPA produced reserpine-sensitive dissipation of the electron-dense aggregates, compatible with the idea that increased amine delivery raised intragranular pH. 6. The data suggest that the processes of amine precursor uptake, decarboxylation and sequestration in secretory granules are associated with selective modulation of progastrin cleavage, possibly by raising intragranular pH and thereby inhibiting pH-sensitive prohormone convertases.

Adrenergic Uptake Inhibitors↗
PubMed1983

Storage of biogenic amines in guinea-pig brain synaptosomes: influence of proton gradient and membrane potential.

1 The effects of K(+), NaCN and the ionophores monensin, nonactin and carbonyl-cyanide-p-trifluoro-methoxyphenylhydrazone (FCCP) on the contents of [(3)H]-5-hydroxytryptamine ([(3)H]-5-HT), [(3)H]-dopamine and [(3)H]-noradrenaline ([(3)H]-NA) in guinea-pig synaptosomes preloaded with these amines were measured.2 In the presence of Ca(2+), K(+) markedly reduced the amine content of the synaptosomes, indicating an acceleration of spontaneous amine release. In the absence of Ca(2+), K(+) had much less effect.3 Monensin, nonactin and FCCP caused a release of all the three labelled amines. This release was considerably faster and more marked than that induced by K(+) and showed no dependence on Ca(2+). The ionophores did not release lactate-dehydrogenase from synaptosomes.4 NaCN, a blocker of oxidative energy production, did not enhance the spontaneous release of [(3)H]-5-HT nor did it influence the monensin-induced release of [(3)H]-5-HT.5 It is concluded that (a) the intragranular storage of 5-HT, dopamine and NA is dependent on the maintenance of a pH-gradient across the granular membrane as well as on the granular membrane potential; (b) the ionophores cause a non-exocytotic release of granular amines, and (c) blood platelets are partial models for aminergic brain neurones as far as intragranular amine storage is concerned.

Animals↗
PubMed1975

Intracellular distribution of amines taken up by rat mast cells.

Mast cells isolated from rat peritoneal and pleural cavities were incubated in vitro with radioactively-labelled histamine (Hi), 5-hydroxytryptamine (5-HT), dopamine (DA), noradrenaline (NA), tyramine (TA), phenylethylamine (PhEA), trptamine (TrpA), ephedrine (Eph) or amphetamine (Amph). All these amines were taken up by the mast cells. The dose-response curves for the compound 48/80-induced release of endogenous Hi and for the various amines taken up by the cells were compared. The release curves for Hi, 5-HT, DA, NA and TA were found to be similar to that for endogenous Hi, while those for PhEA, TrpA, Eph and Amph were different from that for endogenous Hi. The uptake of Hi, 5-HT, DA, PhEA, TrpA and Eph into granules in mast cells was studied. Membrane-bound granules were obtained by sonication of mast cells incubated with the respective amine, followed by differential contrifugation. The amine content of these granules was then measured. Hi, 5-HT and DA were found to be mainly localized to the granules, while a smaller proportion of the PhEA, TrpA and Eph was found there, the rest being located extragranularly. The present results suggest that, when taken up by rat mast cells, even amines which are not endogenous to the cells are stored in the same way as the endogenous amines Hi and 5-HT.

Amines↗
PubMed2001

Amphetamine, 3,4-methylenedioxymethamphetamine, lysergic acid diethylamide, and metabolites of the catecholamine neurotransmitters are agonists of a rat trace amine receptor.

The trace amine para-tyramine is structurally and functionally related to the amphetamines and the biogenic amine neurotransmitters. It is currently thought that the biological activities elicited by trace amines such as p-tyramine and the psychostimulant amphetamines are manifestations of their ability to inhibit the clearance of extracellular transmitter and/or stimulate the efflux of transmitter from intracellular stores. Here we report the discovery and pharmacological characterization of a rat G protein-coupled receptor that stimulates the production of cAMP when exposed to the trace amines p-tyramine, beta-phenethylamine, tryptamine, and octopamine. An extensive pharmacological survey revealed that psychostimulant and hallucinogenic amphetamines, numerous ergoline derivatives, adrenergic ligands, and 3-methylated metabolites of the catecholamine neurotransmitters are also good agonists at the rat trace amine receptor 1 (rTAR1). These results suggest that the trace amines and catecholamine metabolites may serve as the endogenous ligands of a novel intercellular signaling system found widely throughout the vertebrate brain and periphery. Furthermore, the discovery that amphetamines, including 3,4-methylenedioxymethamphetamine (MDMA; "ecstasy"), are potent rTAR1 agonists suggests that the effects of these widely used drugs may be mediated in part by this receptor as well as their previously characterized targets, the neurotransmitter transporter proteins.

Amino Acid Sequence↗
PubMed1977

Polymers of biogenic amines.

Biogenic amines, with a primary amino group, were reacted with glutaraldehyde to form insoluble precipitates. These precipitates had distinctive ultrastructural features upon further reaction with osmic acid. When tested in vitro, they had biological activity and showed evidence that part of this biological activity was due to the large polymer of glutaraldehyde and amine. Experiments with isotope-labelled amines in the production of these precipitates showed that the precipitated polymers were not completely stable and that free amine was liberated from them. Since they were not stable, , they could not be used for the morphological localization of the amines as had been intended, but they may have some use as depot drugs or in the immunization of animals against these amines.

Animals↗