Stereoselective metabolism of famprofazone in humans: N-dealkylation and β-and p-hydroxylation

Following administration of famprofazone to humans, the stereoselective metabolism from the drug to its known metabolites (+,−)-ephedrine, (+,−)-pseudoephedrine, (+,−)-norephedrine, (+,−)-norpseudoephedrine, (+,−)-p-hydroxy-amphetamine, (+,−)-p-hydroxymethamphetamine, and (+,−)-p-hydroxynorephedrine was studied. The enantiomers of the metabolites were derivatized with α-methoxy-α-(trifluoromethyl)-phenylacetyl chloride (MTPA.Cl) as the chiral derivatizing agent for amino groups and N-methyl-N-trimethylsilyl trifluoroacetamide (MSTFA) or N-methyl-N-triethylsilyl trifluoroacetamide (MTESTFA) as protecting agents of the hydroxyl groups. The diastereomeric derivatives were well separated by capillary gas-liquid chromatography and determined by mass spectrometry with selected-ion monitoring (SIM). (−)-Methamphetamine, (−)-amphetamine, (−)-p-hydroxyamphetamine, and-(−)-hydroxymethamphetamine were excreted in greater amounts than their enantiomers after administration of racemic famprofazone; and (−)-ephedrine, (−)-pseudoephedrine, (−)-norephedrine, and (−)-norpseudoephedrine were found in higher concentration than their enantiomers. Famprofazone was metabolized by product and substrate stereoselective N-dealkylation, β-hydroxylation, and p-hydroxylation, metabolites of which may be predominantly responsible for the side effects of famprofazone. Chirality 9:52–58, 1997. © 1997 Wiley-Liss, Inc.     

Composition and stereochemistry of ephedrine alkaloids accumulation in Ephedra sinica Stapf

Ephedra sinica Stapf (Ephedraceae) is a widely used Chinese medicinal plant (Chinese name: Ma Huang). The main active constituents of E. sinica are the unique and taxonomically restricted adrenergic agonists phenylpropylamino alkaloids, also known as ephedrine alkaloids: (1R,2S)-norephedrine (1S,2S)-norpseudoephedrine, (1R,2S)-ephedrine, (1S,2S)-pseudoephedrine, (1R,2S)-N-methylephedrine and (1S,2S)-N-methylpseudoephedrine. GC–MS analysis of freshly picked young E. sinica stems enabled the detection of 1-phenylpropane-1,2-dione and (S)-cathinone, the first two putative committed biosynthetic precursors to the ephedrine alkaloids. These metabolites are only present in young E. sinica stems and not in mature stems or roots. The related Ephedra foemina and Ephedra foliata also lack ephedrine alkaloids and their metabolic precursors in their aerial parts. A marked diversity in the ephedrine alkaloids content and stereochemical composition in 16 different E. sinica accessions growing under the same environmental conditions was revealed, indicating genetic control of these traits. The accessions can be classified into two groups according to the stereochemistry of the products accumulated: a group that displayed only 1R stereoisomers, and a group that displayed both 1S and 1R stereoisomers. (S)-cathinone reductase activities were detected in E. sinica stems capable of reducing (S)-cathinone to (1R,2S)-norephedrine and (1S,2S)-norpseudoephedrine in the presence of NADH. The proportion of the diastereoisomers formed varied according to the accession tested. A (1R,2S)-norephedrine N-methyltransferase capable of converting (1R,2S)-norephedrine to (1R,2S)-ephedrine in the presence of S-adenosylmethionine (SAM) was also detected in E. sinica stems. Our studies further support the notion that 1-phenylpropane-1,2-dione and (S)-cathinone are biosynthetic precursors of the ephedrine alkaloids in E. sinica stems and that the activity of (S)-cathinone reductases directs and determines the stereochemical branching of the pathway. Further methylations are likely due to N-methyltransferase activities.     

Thermogenic and anorectic effects of ephedrine and congeners in mice and rats

(?)-Ephedrine has been shown to increase energy expenditure and cause the loss of body fat in rats and mice. The present study compares the effects of (?)- and (+)-ephedrine, (?)- and (+)- pseudoephedrine, (±)- and (+)-norephedrine and (?)- and (+)-norpseudoephedrine on food intake, energy expenditure and body composition in $\text{ob}$/$\text{ob}$ and normal mice and food intake in rats. The most potent anorectic and thermogenic compounds had the S configuration at the C-2 position but the orders of potencies for the compounds for anorexia and thermogenesis were not identical. The potencies of the compounds in reducing body lipid content correlated better with their thermogenic than their anorectic potencies.     

Expressed sequence tag analysis of khat (Catha edulis) provides a putative molecular biochemical basis for the biosynthesis of phenylpropylamino alkaloids

Khat (Catha edulis Forsk.) is a flowering perennial shrub cultivated for its neurostimulant properties resulting mainly from the occurrence of (S)-cathinone in young leaves. The biosynthesis of (S)-cathinone and the related phenylpropylamino alkaloids (1S,2S)-cathine and (1R,2S)-norephedrine is not well characterized in plants. We prepared a cDNA library from young khat leaves and sequenced 4,896 random clones, generating an expressed sequence tag (EST) library of 3,293 unigenes. Putative functions were assigned to > 98% of the ESTs, providing a key resource for gene discovery. Candidates potentially involved at various stages of phenylpropylamino alkaloid biosynthesis from L-phenylalanine to (1S,2S)-cathine were identified.     

Benzylic alcohols as stereospecific substrates and inhibitors for aryl sulfotransferase

Aryl sulfotransferase IV catalyzes the 3'-phosphoadenosine-5'-phosphosulfate (PAPS)-dependent formation of sulfuric acid esters of benzylic alcohols. Since the benzylic carbon bearing the hydroxyl group can be asymmetric, the possibility of stereochemical control of substrate specificity of the sulfotransferase was investigated with benzylic alcohols. Benzylic alcohols of known stereochemistry were examined as potential substrates and inhibitors for the homogeneous enzyme purified from rat liver. For 1-phenylethanol, both the (+)-(R)- and (-)-(S)-enantiomers were substrates for the enzyme, and the kcat/Km value for the (-)-(S)-enantiomer was twice that of the (+)-(R)-enantiomer. The enzyme displayed an absolute stereospecificity with ephedrine and pseudoephedrine, and with 2-methyl-1-phenyl-1-propanol; that is, only (-)-(1R,2S)-ephedrine, (-)-(1R,2R)-pseudoephedrine, and (-)-(S)-2-methyl-1-phenyl-1-propanol were substrates for the sulfotransferase. In the case of 1,2,3,4-tetrahydro-1-naphthol, only the (-)-(R)-enantiomer was a substrate for the enzyme. Both (+)-(R)-2-methyl-1-phenyl-1-propanol and (+)-(S)-1,2,3,4-tetrahydro-1-naphthol were competitive inhibitors of the aryl sulfotransferase-catalyzed sulfation of 1-naphthalenemethanol. Thus, the configuration of the benzylic carbon bearing the hydroxyl group determined whether these benzylic alcohols were substrates or inhibitors of the rat hepatic aryl sulfotransferase IV. Furthermore, benzylic alcohols such as (+)-(S)-1,2,3,4-tetrahydro-1-naphthol represent a new class of inhibitors for the aryl sulfotransferase.     

Stoichiometry of interaction between soluble (—)-dopa melanin and enantiomers of ephedrine by NMR spectroscopy

Synthetic soluble (—)-dopa melanin was prepared in deuteriated buffer, pH 8, by autooxidation of the precursor. At 6 mM of the precursor, the incorporation was over 90%. The changes in the line width measurements of N-CH₃ protons of enantiomers of ephedrine in the soluble melanin were quantified by NMR spectroscopy. The dissociation constants of (—)-1R,2S-ephedrine, (+)-1S,2R-ephedrine, (—)-1R,2R-ψ-ephedrine, and (+)-1S,2S-ψ-ephedrine were 11.7, 4.20, 3.60, and 4.80 mM, respectively. Since the concentration of (—)-dopa was known and since the conversion of (—)-dopa to indole units of melanin was considered as 1:1, the stoichiometry of the interaction between the drug and the indole unit was calculated. Based on the dissociation constants of the enantiomers, it appears that up to four molecules of (—)-ephedrine can interact with one indole unit of the melanin, while such a ratio for other isomers appear to be 2:1. The preference by indole units of melanin is stereoselective. © 1992 Wiley-Liss, Inc.     

Influence of continuous magnetic field on the separation of ephedrine enantiomers by molecularly imprinted polymers

A set of polymers was imprinted with (-)-ephedrine using UV initiation, under the influence of a constant external magnetic field with intensities ranging from 0 to 1.55 T. Synthesised materials were characterised by X-ray crystallography, infrared spectroscopy, swelling and surface area. Recognition properties were assessed by the ability to discriminate between (+) and (-)-ephedrine and by Scatchard analyses on chromatographic mode. It was shown that polymer morphology and recognition properties are affected by the magnetic field. This resulted in considerable improvements in the chromatographic resolution of ephedrine enantiomers by materials synthesised under the influence of magnetic field. Apparently the magnetic field improved the ordering of the polymer structure and facilitated the formation of more uniform imprinting sites.     

Benzaldehyde is a precursor of phenylpropylamino alkaloids as revealed by targeted metabolic profiling and comparative biochemical analyses in Ephedra spp.

Ephedrine and pseudoephedrine are phenylpropylamino alkaloids widely used in modern medicine. Some Ephedra species such as E. sinica Stapf (Ephedraceae), a widely used Chinese medicinal plant (Chinese name: Ma Huang), accumulate ephedrine alkaloids as active constituents. Other Ephedra species, such as E. foeminea Forssk. (syn. E. campylopoda C.A. Mey) lack ephedrine alkaloids and their postulated metabolic precursors 1-phenylpropane-1,2-dione and (S)-cathinone. Solid-phase microextraction analysis of freshly picked young E. sinica and E. foeminea stems revealed the presence of increased benzaldehyde levels in E. foeminea, whereas 1-phenylpropane-1,2-dione was detected only in E. sinica. Soluble protein preparations from E. sinica and E. foeminea stems catalyzed the conversion of benzaldehyde and pyruvate to (R)-phenylacetylcarbinol, (S)-phenylacetylcarbinol, (R)-2-hydroxypropiophenone (S)-2-hydroxypropiophenone and 1-phenylpropane-1,2-dione. The activity, termed benzaldehyde carboxyligase (BCL) required the presence of magnesium and thiamine pyrophosphate and was 40 times higher in E. sinica as compared to E. foeminea. The distribution patterns of BCL activity in E. sinica tissues correlates well with the distribution pattern of the ephedrine alkaloids. (S)-Cathinone reductase enzymatic activities generating (1R,2S)-norephedrine and (1S,1R)-norephedrine were significantly higher in E. sinica relative to the levels displayed by E. foeminea. Surprisingly, (1R,2S)-norephedrine N-methyltransferase activity which is a downstream enzyme in ephedrine biosynthesis was significantly higher in E. foeminea than in E. sinica. Our studies further support that benzaldehyde is the metabolic precursor to phenylpropylamino alkaloids in E. sinica.     

Enzymatic synthesis of l-norephedrine by coupling recombinant pyruvate decarboxylase and ω-transaminase

l-Norephedrine, a natural plant alkaloid, possesses similar activity as ephedrine and can be used as a vicinal amino alcohol for the asymmetric synthesis of a variety of optically pure compounds, including pharmaceuticals, fine chemicals, and agrochemicals. Because of the existence of two asymmetric centers, efficient synthesis of l-norephedrine has been challenging. In the present study, an R-selective pyruvate decarboxylase from Saccharomyces cerevisiae and an S-selective ω-transaminase from Vibrio fluvialis JS17 were coupled to develop a sequential process for the stereoselective biosynthesis of l-norephedrine. After systematic optimization of the reaction conditions, a green, economic, and practical biocatalytic method to prepare l-norephedrine was established to achieve de and ee values of greater than 99.5 % and a molar yield over 60 %. The present coupling approach can facilitate the development of sequential reactions by various biocatalysts.     

Sensitive quantification of omeprazole and its metabolites in human plasma by liquid chromatography-mass spectrometry

A sensitive method was developed for the simultaneous determination of omeprazole and its major metabolites 5-hydroxyomeprazole and omeprazole sulfone in human plasma by HPLC-electrospray mass spectrometry. Following liquid-liquid extraction HPLC separation was achieved on a ProntoSil AQ, C18 column using a gradient with 10 mM ammonium acetate in water (pH 7.25) and acetonitrile. The mass spectrometer was operated in the selected ion monitoring mode using the respective MH(+) ions, m/z 346 for omeprazole, m/z 362 for 5-hydroxy-omeprazole and omeprazol-sulfone and m/z 300 for the internal standard (2-{[(3,5-dimethylpyridine-2-yl)methyl]thio}-1H-benzimidazole-5-yl)methanol. The limit of quantification (LOQ) achieved with this method was 5 ng/ml for 5-hydroxyomeprazole and 10 ng/ml for omeprazole and omeprazole-sulfone using 0.25 ml of plasma. Intra- and inter-assay variability was below 11% over the whole concentration range from 5 to 250 ng/ml for 5-hydroxyomeprazol and from 10 to 750 ng/ml for omeprazole and omeprazole-sulfone. The method was successfully applied to the determination of pharmacokinetic parameters of esomeprazole and the two major metabolites after a single dose and under steady state conditions.     

Improved high-performance liquid chromatographic method to estimate aminosugars and its application to glycosaminoglycan determination in plasma and serum

An improved isocratic high-performance liquid chromatography (HPLC) method for the analysis of -(−)-fucose, -(+)-galactosamine, -(+)-glucosamine, -(+)-galactose, obtained by hydrolysis of glycosaminoglycans (GAGs) and -(+)-glucose and -(+)-mannose is described. The presence in circulation of GAGs, acid polysaccharide sequences of alternate monosaccharide units, aminosugar and uronic acid (galactose in keratan sulfate), has been measured in terms of their sugar components. To evaluate concentration of these circulating sugars we considered blood samples obtained from healthy humans. Plasma or serum was filtered through weak anion-exchange Ecteola-cellulose either untreated or after mild alkaline treatment. GAGs adhering to resin were recovered by salt elution, and desalted on Bio-Gel P-2 resin. GAG fractionation by charge was carried out on a strong anion exchanger. GAG composition was evaluated in terms of galactose and aminosugars, measured in HPLC by the proposed procedure using anion-exchange resin and pulsed amperometric detection. The mobile phase consisted of 0.02 M NaOH and elution was carried out at flow-rate of 1.0 ml/min. The amperometric detector was set as follows: t₁ (0.5 s), E₁ (+0.1 V); t₂ (0.09 s), E₂ (+0.6 V); t₃ (0.05 s), E₃ (−0.6 V). The analysis required 14 min. Calibration standard curves for the six analytes were linear from 0.25 to 40 μM. RSD values for intra- and inter-day variabilities were ≤5.3% at concentrations between 0.25 and 40 μM. Accuracy, expressed as percentage error, ranged from −16 to 14%. The method was specific and sensitive with quantitation limits of 1 pmol for -(−)-fucose, -galactosamine and -glucosamine, 3 pmol for -(+)-galactose and -(+)-glucose and 5 pmol for -(+)-mannose. The results of the assay showed higher GAG concentrations in serum than in plasma.     

Influence of initiator and different polymerisation conditions on performance of molecularly imprinted polymers

A set of polymers was imprinted with (-)-ephedrine using two different initiators. A chemometrics approach was used to optimise experiments aimed at analysis of the interplay of parameters such as polymerisation time, temperature and percentage of initiator. The results presented demonstrate the importance of keeping the right balance between these various parameters of polymerisation conditions. It is shown that enhancing one single parameter such as polymer rigidity does not necessarily improve polymer performance. In general it could be concluded that MIPs should be synthesised over a long period of time using low concentration of initiator and low temperature. The best selectivity was achieved for polymers prepared by photo-initiation with 2,2-dimethoxy-2-phenylacetophenone as initiator.     

Dihydroflavonols from Lannea coromandelica

The dihydroflavonols, (2R,3S)-(+)-3',5-dihydroxy-4',7-dimethoxydihydroflavonol and (2R,3R)-(+)-4',5,7-trimethoxydihydroflavonol were isolated from the stem bark of Lannea coromandelica, along with the known (2R,3R)-(+)-4',7-di-O-methyldihydroquercetin, (2R,3R)-(+)-4',7-di-O-methyldihydrokaempferol and (2R,3R)-(+)-4'-O-methyldihydroquercetin. All five compounds were isolated for the first time from the genus Lannea; furthermore, (2R,3S)-(+)-3',5-dihydroxy-4',7-dimethoxydihydroflavonol, was a rare cis-type isomer. The structures of all compounds were elucidated by spectroscopic methods including 2D NMR and CD analysis.     

Optimization of <Emphasis Type="Italic">R</Emphasis>-(+)-α-terpineol production by the biotransformation of <Emphasis Type="Italic">R</Emphasis>-(+)-limonene

R-(+)-limonene is an abundant and non-expensive by-product of the citrus industry and is, therefore, a suitable starting material for the production of natural flavor and fragrance compounds. The biotransformation of R-(+)-limonene to R-(+)-alpha-terpineol by Fusarium oxysporum 152b has already been reported, although the influence of the main process parameters on the production has not yet been evaluated. In this paper, a Plackett-Burman screening design was used to define the effects of the medium composition (glucose, peptone, yeast extract, malt extract and pH), the presence of a co-substrate (biosurfactant), the cultivation conditions (temperature, agitation), the substrate concentration and the inoculum/culture medium ratio on the absolute amount of R-(+)-alpha-terpineol resulting from this biotransformation. The process conditions were further optimized applying response surface methodology (RSM). The volatiles were extracted using a SPME device and were subsequently quantified by GC-FID and identified by GC-MS. The best results were obtained using 0.5% (v/m) R-(+)-limonene in pure distilled water as the culture medium with an inoculum/culture medium ratio of 0.25 (m/m) and 72 h cultivation at 26 degrees C/240 rpm. Under these conditions the concentration of R-(+)-alpha-terpineol in the culture medium reached 2.4 g L(-1), a production almost six times greater than in earlier trials. The presence of a biosurfactant (0-500 mg L(-1)) did not significantly increase the yield.     

Application of Dibenzoate Chirality Rule to Flexible Systems

The chiroptical properties of (+)-(1S,2S)-dibenzoxycycloheptane and (+)-(lS,2S)-dibenzoxycyclooctane were observed. The dibenzoate chirality rule for chiral dibenzoxycyclohexanes was successfully applicable to these medium-sized ring compounds as well. The conformation of the open chain dibenzoates was discussed on the basis of the chiroptical properties found for the dibenzoate and di-p-nitrobenzoate of (+)-(2S,3S)-butane-diol.     

Enantioselective analysis of unbound tramadol, O-desmethyltramadol and N-desmethyltramadol in plasma by ultrafiltration and LC-MS/MS: application to clinical pharmacokinetics

This study describes the enantioselective analysis of unbound and total concentrations of tramadol and its main metabolites O-desmethyltramadol (M1) and N-desmethyltramadol (M2) in human plasma. Sample preparation was preceded by an ultrafiltration step to separate the unbound drug. Both the ultrafiltrate and plasma samples were submitted to liquid/liquid extraction with methyl t-butyl ether. Separation was performed on a Chiralpak(?) AD column and tandem mass spectrometry consisting of an electrospray ionization source, positive ion mode and multiple reaction monitoring was used as the detection system. Linearity was observed in the following ranges: 0.2-600 and 0.5-250 ng/mL for analysis of total and unbound concentrations of the tramadol enantiomers, respectively, and 0.1-300 and 0.25-125 ng/mL for total and unbound concentrations of the M1 and M2 enantiomers, respectively. The lower limits of quantitation were 0.2 and 0.5 ng/mL for analysis of total and unbound concentration of each tramadol enantiomer, respectively, and 0.1 and 0.25 ng/mL for total and unbound concentrations of M1 and M2 enantiomers, respectively. Intra- and interassay reproducibility and inaccuracy did not exceed 15%. Clinical application of the method to patients with neuropathic pain showed plasma accumulation of (+)-tramadol and (+)-M2 after a single oral dose of racemic tramadol. Fractions unbound of tramadol, M1 or M2 were not enantioselective in the patients investigated.     

Erythrinaline alkaloids from the flowers and pods of Erythrina lysistemon and their DPPH radical scavenging properties

Fourteen different erythrinaline alkaloids have been isolated from the flowers and pods of Erythrina lysistemon with four being reported for the first time in nature and five for the first time in this species and the rest having been re-isolated. The new compounds are (+)-11beta-hydroxyerysotramidine (1), (+)-11beta-methoxyerysotramidine (2), (+)-11beta-hydroxyerysotrine N-oxide (4) and (+)-11beta-hydroxyerysotrine (8). (+)-11alpha-Hydroxyerysotrine N-oxide (3), earlier misidentified as erythrartine N-oxide (beta-hydroxyerysotrine N-oxide 4), was also re-isolated along with four other alkaloids. Correct identification of compounds 4 and 8 was aided by the fact that the two sets of C-11 epimers 3, 4 and 8, 9 were both isolated in this study thus making it easier to identify and assign the individual epimers. (+)-Erythristemine (14) was found distributed in most of the plant parts investigated. Preliminary work on the crude chloroform/methanol (1:1) showed moderate toxicity to brine shrimp (LC50 23 ppm) and moderate (IC50 86 microg/ml) radical scavenging properties against stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The DPPH radical scavenging properties of the isolated compounds were assessed using TLC autographic and spectrophotometric assays whereupon only compounds 11 (1 microg; 90 microg/ml) and 12 (0.1 microg; 160 microg/ml) showed any notable activity. It appears the two compounds are slow reacting and do not reach steady state conditions within the standard half an hour time frame but only seemed to have reached steady state conditions after 4 h.     

Pinoresinol-lariciresinol reductases with different stereospecificity from Linum album and Linum usitatissimum

Recently it was found that cell cultures and plants of Linum species contain lignans of various chemical structures. The stereochemistry of these compounds differ among species. Cell cultures of L. album accumulate (-)-podophyllotoxin together with pure (-)-secoisolariciresinol. The presence of both enantiomers of the precursor pinoresinol indicates that in L. album cell cultures the reactions from pinoresinol to secoisolariciresinol are the first steps determining enantiospecificity in biosynthesis of podophyllotoxin. Seeds of L. usitatissimum contain almost enantiomerically pure (+)-secoisolariciresinoldiglucosid derived from (+)-secoisolariciresinol. A cell culture of this species contains a mixture of both enantiomers of pinoresinol and pure (+)-secoisolariciresinol. In order to get more insight into the mechanism of (-)- and (+)-secoisolariciresinol biosynthesis, respectively, we isolated a cDNA encoding pinoresinol-lariciresinol reductase (PLR) from L. album. The heterologously expressed PLR-La1 converts only (+)-pinoresinol into (-)-secoisolariciresinol. In contrast, the heterologously expressed PLR from L. usitatissimum converts only (-)-pinoresinol to (+)-secoisolariciresinol confirming the results from others. Comparison of all available PLR protein sequences resulted in a few amino acids which may be responsible for the action of the PLRs with respect to the different enantioselectivity. A mutagenesis approach could not confirm this hypothesis. Aspects about the evolution of PLRs are discussed.     

(+)-12alpha-Hydroxysophocarpine, a new quinolizidine alkaloid and related anti-HBV alkaloids from Sophora flavescens

(+)-12alpha-Hydroxysophocarpine (8), a new quinolizidine alkaloid was isolated from the roots of Sophora flavescens, together with 10 known quinolizidine alkaloids, (+)-oxymatrine (1), (+)-matrine (2), (+)-9alpha-hydroxymatrine (3), (+)-allomatrine (4), (+)-oxysophocarpine (5), (-)-sophocarpine (6), (-)-9alpha-hydroxysophocarpine (7), (+)-lehmannine (9), (-)-13,14-dehydrosophoridine (10), and (-)-anagyrine (11). Their structures were elucidated by spectroscopic methods, and the stereochemistry of 8 was confirmed by X-ray analysis. These alkaloids were tested for anti-hepatitis B virus (HBV) activity in vitro, compounds 5, 6, 9, and 10 showed significant anti-HBV activity with inhibitory potency against HBsAg secretion at 48.3-79.3% and that against HBeAg secretion at 24.6-34.6%.     

Development of an ionic liquid-based ultrasonic-assisted liquid-liquid microextraction method for sensitive determination of biogenic amines: application to the analysis of octopamine, tyramine and phenethylamine in beer samples

A simple and efficient method, ionic liquid-based ultrasound-assisted liquid-liquid microextraction, has been developed for the determination of three biogenic amines including octopamine (OCT), tyramine (TYR) and phenethylamine (PHE). Fluorescence probe 2,6-dimethyl-4-quinolinecarboxylic acid N-hydroxysuccinimide ester was applied for derivatization of biogenic amines and high-performance liquid chromatography coupled with fluorescence detection was used for the determination of the derivatives. The factors affecting the extraction efficiency, such as the type and volume of ionic liquid, ultrasonication time and centrifugation time have been investigated in detail. Under the optimum conditions, linearity of the method was observed in the range of 0.5-50 μgmL(-1) for OCT and TYR, and 0.025-2.5 μgmL(-1) for PHE, respectively, with correlation coefficients (γ)>0.996. The limits of detection ranged from 0.25-50 ngmL(-1) (S/N=3). The spiked recoveries of three target compounds in beer samples were in the range of 90.2-114%. As a result, this method has been successfully applied for the sensitive determination of OCT, TYR and PHE in beer samples.