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PubMed2003

Determination of ephedrine alkaloids and synephrine in dietary supplements by column-switching cation exchange high-performance liquid chromatography with scanning-wavelength ultraviolet and fluorescence detection.

An HPLC method with on-line cleanup coupled to the separation column is described for determination of (-)-norephedrine, (+)-norpseudoephedrine, (-)-ephedrine, (+)-pseudoephedrine, (-)-N-methylephedrine, (+)-N-methylpseudoephedrine, and (+/-)-synephrine in finished dietary supplement products. Test portions were extracted in acidified aqueous acetone. A filtered aliquot was cleaned up on a strong cation exchange (SCX) precolumn that later was automatically coupled to the SCX analytical column. Measurement was by full-scan UV spectra for confirmation of identity by spectral matching and real-time integration of three wavelength signals for multiple quantitation. (+/-)-Synephrine was also quantitated by native fluorescence. Recovery averaged 95-100%. Determination of the major ingredients (-)-ephedrine, (+)-pseudoephedrine, and (+/-)-synephrine compared favorably to findings by an independent LC-MS analysis for a set of 25 samples. The results of a survey were reported for total ephedrine alkaloid and synephrine content and were compared to content declaration, for approximately 48 finished products.

Alkaloids↗
PubMed2001

Seville (sour) orange juice: synephrine content and cardiovascular effects in normotensive adults.

The Seville orange extract Citrus aurantium contains m-synephrine (phenylephrine) and octopamine; it causes cardiac disturbances in animals and is used by humans for weight loss. Juice from the orange (Seville orange juice [SOJ]) is used to "knock out" intestinal cytochrome P450 (CYP) 3A4 in bioavailability studies. The purpose of this study was to determine synephrine and octopamine concentrations in SOJ and SOJ's cardiovascular effects in normotensive humans. Subjects consumed 8 ounces of SOJ and water in crossover fashion followed by a repeat ingestion 8 hours later. Hemodynamic (heart rate; systolic, diastolic, and mean arterial pressure) measurements followed. Synephrine and octopamine were determined by high-performance liquid chromatography. Hemodynamics did not differ significantly between water and SOJ groups. Mean synephrine concentration of SOJ samples was 56.9 +/- 0.52 microg/ml; octopamine was not detected. SOJ ingestion by normotensive subjects is expected to be safe. Individuals with severe hypertension, tachyarrhythmias, and narrow-angle glaucoma and monoamine oxidase inhibitor recipients should avoid SOJ consumption. Persons taking decongestant-containing cold preparations should also refrain from SOJ intake.

Adult↗
PubMed2005

Ischemic stroke associated with use of an ephedra-free dietary supplement containing synephrine.

In response to concerns regarding the safety of ephedra-containing dietary supplements, manufacturers have marketed "ephedra-free" products. Many of these contain synephrine, a sympathomimetic amine from the plant Citrus aurantium. Synephrine is structurally similar to ephedrine and has vasoconstrictor properties. We describe a 38-year-old patient with ischemic stroke associated with an ephedra-free dietary supplement containing synephrine and caffeine. The patient presented with memory loss and unsteady gait after taking 1 or 2 capsules per day of a dietary supplement (Stacker 2 Ephedra-Free) for 1 week. He had no notable medical history or major atherosclerotic risk factors and took no other medications. Physical examination showed a mildly ataxic gait and substantial Impairment of both concentration and memory. Computed tomography and magnetic resonance Imaging of the brain showed subacute infarctions in the left thalamus and left cerebellum in the distribution of the vertebrobasilar circulation. Other causes of ischemic stroke were evaluated, and findings were unremarkable; a vasospastic origin was considered most likely. The patient was discharged with nearly complete resolution of symptoms. Synephrine, a sympathomimetic amine related to ephedrine, may be associated with Ischemic stroke. Consumers and clinicians need to be Informed about the potential risks of ephedra-free products.

Adult↗
PubMed1978

[Pharmacokinetics and metabolism of 3H-synephrine (author's transl)].

The physiological disposition of 1-(4-hydroxyphenyl)-2-methylamino-ethanol-tartrate (synephrine, Sympatol) in man had not been investigated to date. Therefore, we studied pharmacokinetics and metabolism of tritiated synephrine in man. Following short i.v. infusion in six patients about 80% of the administered radioactivity was recovered in urine. Two-thirds of the urinary tritium activity consisted of the deaminated p-hydroxymandelic acid. 10% were excreted as unchanged synephrine only. Following oral ingestion in ten patients the total urinary radioactivity was quite comparable to the i.v. experiments. Therefore, complete enteric absorption has to be stated. The amount of unchanged synephrine amounted, however, only to 2.5% of the dose. The resulting bioavailability has to be calculated to 22% only. The pharmacokinetic parameters are quite comparable to the sympathomimetics similar in structure. The biological half-life was about 2 h. After oral ingestion absorption was fast, the peak concentrations were observed between 1 and 2 h after administration.

Administration, Oral↗
PubMed2006

Citrus aurantium and synephrine alkaloids in the treatment of overweight and obesity: an update.

Obesity is a major health problem facing the developed and developing world. Efforts by individuals, health professionals, educators, and policy makers to combat the escalating trend of growing obesity prevalence have been multifaceted and mixed in outcome. Various dietary supplements have been marketed to reduce obesity. These products have been suggested to accomplish this by decreasing energy intake and energy absorption, and/or increasing metabolic rate. Ephedra, one such supplement, was banned from sale in the US market because of concerns about adverse events. Another substance, Citrus aurantium, which contains several compounds including synephrine alkaloids, has been suggested as a safe alternative. This review examines the evidence for safety and efficacy of C. aurantium and synephrine alkaloids as examined in animal studies, clinical weight loss trials, acute physiologic studies and case reports. Although at least three reviews of C. aurantium have been published, our review expands upon these by: (i) distinguishing and evaluating the efficacy of C. aurantium and related compounds; (ii) including results from previously unreviewed research; (iii) incorporating recent case reports that serve to highlight, in an anecdotal way, potential adverse events related to the use of C. aurantium and related compounds; and (iv) offering recommendations to guide the design of future trials to evaluate the safety and efficacy of C. aurantium. While some evidence is promising, we conclude that larger and more rigorous clinical trials are necessary to draw adequate conclusions regarding the safety and efficacy of C. aurantium and synephrine alkaloids for promoting weight loss.

Alkaloids↗
PubMed1975

Microbial metabolism of phenolic amines: degradation of dl-synephrine by an unidentified arthrobacter.

Microorganisms capable of degrading dl-synephrine were isolated from soil of Citrus gardens by enrichment culture, with dl-synephrine as the sole source of carbon and nitrogen. An organism which appears to be an arthrobacter, but which cannot be identified with any of the presently recognized species was predominant in these isolates. It was found to metabolize synephrine by a pathway involving p-hydroxyphenylacetaldehyde, p-hydroxyphenylacetic acid, and 3,4-dihydroxyphenylacetic acid as intermediates. Some of the enzymes of this pathway were demonstrated in cell-free extracts. An aromatic oxygenase, which could also be readily obtained in a cell-free system, was found to degrade 3,4-dihydroxyphenylacetic acid by meta cleavage.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

[Studies on the preparation and evaluation of Kijitsu, the immature citrus fruits. III. Relation between diameter of Kijitsu and synephrine content].

For the purpose of evaluating Kijitsu, the content of synephrine in dried unripe citrus fruits was analyzed by high performance liquid chromatography after cleaning up the MeOH extract with an ion exchange cellulose column. Among them, Citrus unshiu had the highest amount of synephrine. No difference was found between C. hassaku and C. aurantium. The synephrine content decreased corresponding with an increase in diameter of Kijitsu.

Chromatography, High Pressure Liquid↗
PubMed2004

[Determination of synephrine and N-methyltyramine in Pericarpium Citri Reticulatae viride by HPLC].

OBJECTIVE: To establish a quantitative method for determination of synephrine and N-methyltyramine in Citri Reticulatae. METHOD: Samples were extracted with 30% methanol. ODS column was used with methanol-water-sodium dodecyl sulfate (55:45:0.1) as mobile phase. Detection wavelength was 285 nm. RESULT: Synephrine and N-methyltyramine in sample solution were well separated. Linearity of synephrine was good (r = 0.9999) in range of 0.35-11.24 microg. The average recovery was 97.1%, and RSD of repeatability was 1.9%. CONCLUSION: This method can be used for quality control of Citri Reticulatae.

Chromatography, High Pressure Liquid↗
PubMed2006

A new method for fabrication of an integrated indium tin oxide electrode on electrophoresis microchips with amperometric detection and its application for determination of synephrine and hesperidin in pericarpium citri reticulatae.

A new, simple, and fast method to integrate indium tin oxide electrode in an amperometric detection (AD) microchip is introduced. Without the help of photoresist and complicated apparatus, the microchip could be fabricated in most laboratories in a very short time by this method. The experiment indicated that the microchip was stable and had good reproducibility. On this microchip, a new method was established to separate and determine synephrine and hesperidin, which are the main electroactively bioactive ingredients of pericarpium citri reticulatae, by AD. Under the optimal conditions, the two compounds could be completely separated within 5.5 min and the detection limits were 0.13 and 0.57 microg/mL, respectively. The proposed method has been successfully used to determine synephrine and hesperidin in real pericarpium citri reticulatae sample, and the results show that the proposed method is sensitive, reliable, fast, and economical.

Citrus↗
PubMed1992

[Determination of synephrine in oriental pharmaceutical decoctions containing Aurantii nobilis pericarpium by ion-pair high-performance liquid chromatography].

A simple method using ion-pair high-performance liquid chromatography was established for the rapid and precise determination of synephrine in oriental pharmaceutical decoctions containing Aurantii Nobilis Pericarpium. An ODS column and a mixture of water, acetonitrile, sodium dodecyl sulfate and phosphoric acid (65:35:0.5:0.1) as a mobile phase were used for the separation. Synephrine was eluted without interference by other co-existing components within 15 min.

Chromatography, High Pressure Liquid↗
PubMed1993

[Determination of synephrine in Oriental pharmaceutical decoctions containing aurantii nobilis pericarpium by ion-pair high-performance liquid chromatography. II].

A simple method using ion-pair high-performance liquid chromatography was established for the rapid and precise determination of synephrine in thirty three species of oriental pharmaceutical decoctions containing Aurantii Nobilis Pericarpium. An ODS column and a mixed solvent system of water, acetonitrile, sodium dodecyl sulfate and phosphoric acid as a mobile phase were used for the separation. Synephrine was eluted without interference of other coexisting components within 15 min.

Chromatography, High Pressure Liquid↗
PubMed1994

[Determination of synephrine in oriental pharmaceutical decoctions containing evodiae fructus by ion-pair high-performance liquid chromatography].

A simple and precise method was established for the determination of synephrine in oriental pharmaceutical decoctions containing Evodiae Fructus using high-performance liquid chromatography with sodium dodecyl sulfate (SDS) as an ion-pair reagent. Synephrine was eluted within 25 min without interference from co-existing components using an ODS column and a mixture of water-acetonitrile-SDS-phosphoric acid (70:30:0.5:0.1, v/v/w/v) as a mobile phase.

Chromatography, High Pressure Liquid↗
PubMed2000

[Determination of naringin and synephrine in fructus aurantii from different habitats by HPLC].

This paper reports the determination of Naringin and Synephrine in Fructus Aurantii from different habitats by HPLC. The result shows the highest content of Naringin in Citrus aurantium L. 'Xiangcheng' from genuine crude drug habitat Xingan city Jiangxi provice, the highest content of synephrine in Citrus aurantium L. 'Xiangcheng' from Yiyang city Jiangxi provice. Quality evaluation of genuine crude drug was studied preliminarily.

China↗
PubMed1979

Oxidation of synephrine by type A and type B monoamine oxidase.

Synephrine (SP) was found to be a substrate for monoamine oxidase (MAO) in rat brain mitochondria, showing the Km and Vmax values of 250 microM and 32.6 nmoles/mg of protein/30 min respectively. The inhibition studies showed that the SP oxidation was carried out by both type A and type B MAO and a major part of the activity was due to type A MAO.

Animals↗
PubMed2002

Determination of hesperidin and synephrine in Pericarpium Citri Reticulatae by capillary electrophoresis with electrochemical detection.

A method based on capillary electrophoresis with electrochemical detection (CE-ED) has been developed for the determination of hesperidin (HP) and synephrine (SP) in the Chinese traditional herbal drug, Pericarpium Citri Reticulatae, the dried rind of the ripe fruits of Citrus reticulata Blanco (mandarin orange). The effects of some important factors such as the acidity and concentration of running buffer, separation voltage, and detection potential were investigated to determine the optimum conditions. The working electrode was a 300 microm diameter carbon disc electrode positioned opposite the outlet of the capillary. Both analytes could be well separated within 5 min in a 40 cm long capillary at a separation voltage of 12 kV in 50 mmol L(-1) borate buffer (pH 9.0). Excellent linearity was observed for the dependence of peak current on analyte concentration in the range from 2.5 x 10(-6) to 1.0 x 10(-3) mol L(-1) for SP and from 5.0 x 10(-6) to 1.0 x 10(-3) mol L(-1) for HP. The detection limits (S/N=3) for SP and HP were 4.96 x 10(-7) mol L(-1) and 6.54 x 10(-7) mol L(-1), respectively. This method has been successfully applied for the analysis of real samples, with satisfactory results.

Drugs, Chinese Herbal↗
PubMed2006

Determination of octopamine, synephrine and tyramine in Citrus herbs by ionic liquid improved 'green' chromatography.

Without adding any volatile organic solvents, aqueous solutions of room temperature ionic liquids (RTILs) were used as 'green' mobile phases to determine octopamine, synephrine and tyramine by liquid chromatography. The problems of the adrenergic amines separation, such as band tailing, low retention and low resolution were solved successfully by using RTIL. The effect of 1-ethyl-3-methylimidazolium tertafluoroborate ([EMIM][BF4]) was the best in the six investigated RTILs. The concentration of [EMIM][BF4], mobile phase pH and column temperature, which influenced the chromatographic behaviors of the analytes, were investigated in detail. The change of retention factors caused by pH shift was obviously suppressed by [EMIM][BF4]. The sensitivity, accuracy and repeatability of this method were found to be satisfactory. The contents of adrenergic amines in several Citrus herbs and extracts, such as Fructus aurantii immaturus, were simultaneously determined by this 'green' chromatographic method.

Adrenergic alpha-Agonists↗
PubMed2006

An isotopically labeled internal standard liquid chromatography-tandem mass spectrometry method for determination of ephedrine alkaloids and synephrine in dietary supplements.

We report a simplified analytical procedure for determination of ephedrine alkaloids and synephrine in dietary supplements. Cleanup by simple filtration, when combined with tandem mass spectrometry (MS/MS) detection, provided results comparable to our published method with solid phase extraction (SPE) cleanup and single-stage MS detection with in-source fragmentation. We also compared three mass spectrometric experimental configurations: electrospray (ESI) and atmospheric pressure chemical ionization (APCI) with MS/MS and APCI-MS with fragmentation provided by increasing cone voltage. Because these methods used one isotopically labeled internal standard to determine several different analytes, quantitation errors may arise from susceptibility to ionization suppression caused by the matrix. We therefore compared the results obtained by ESI and APCI ionization.

Alkaloids↗