Combination of Ephedra sinica stems and Terminalia chebula fruits produces new ephedrine derivatives in vivo that diminish the permeability to BBB while retaining airway dilation and hepatoprotective effects.

ETHNOPHARMACOLOGICAL RELEVANCE: The stems of Ephedra sinica and the fruits of Terminalia chebula are combined using in traditional Mongolian medicine formula "Gurigumu-7" for liver diseases. E. sinica stems contains ephedrine with broncho-dilatory activity. However, ephedrine can pass through the blood-brain barrier (BBB) and excite the central nervous system (CNS) to cause insomnia and restlessness. AIM OF THE STUDY: The present study was to investigate the structures and bioactivities of new compounds formed in vivo after co-administration of E. sinica stems and T. chebula fruits. MATERIALS AND METHODS: Pharmacokinetic investigation was carried out in rats. A parallel artificial membrane permeability measurement system was used to determine BBB permeability. Ex vivo experiments using tracheal rings of guinea pig was performed to examine the tracheal relaxation effect. In vivo hepatoprotective tests were carried out in Tg (fabp10a: dsRed) liver transgenic zebrafish. The fluorescent probe, 2,7-dichlorodihydrofluorescein diacetate, was used to measure reactive oxygen species, and UHPLC-MS was used to determine glutathione concentrations after derivatization with N-ethylmaleimide. RESULTS: New ephedrine derivatives (1 and 2) formed in vivo and reached their maximum serum concentrations at 0.5 h after administration of the two herbal drugs. Compounds 1 and 2 showed lower BBB permeability than ephedrine, suggesting that they have less adverse effects on the CNS. Compounds 1 and 2 relaxed the tracheal rings and had strong hepatoprotective effect on transgenic zebrafish with liver specific expression of RFP. Compounds 1 and 2 significantly reduced the level of reactive oxygen species while increasing that of glutathione in thioacetamide-treated zebrafish, which might be the hepatoprotective mechanism. CONCLUSION: These results provided evidences that the chemical constituents in various herbal drugs in a medicinal formula can interact to generate new compounds with fewer side effects and increased or additive bioactivity.

A Rapid and Feasible 1H-NMR Quantification Method of Ephedrine Alkaloids in Ephedra Herbal Preparations.

A highly specific and sensitive proton nuclear magnetic resonance (1H-NMR) method has been developed for the quantification of ephedrine alkaloid derivatives in Ephedra herbal commercial prescriptions. At the region of δ 4.0 to 5.0 ppm in the 1H NMR spectrum, the characteristic signals are separated well from each other, and six analogues in total, methylephedrine (ME), ephedrine (EP), norephedrine (NE), norpseudoephedrine (NP), pseudoephedrine (PE), and methylpseudoephedrine (MP) could be identified. The quantities of these compounds are calculated by the relative ratio of the integral values of the target peak for each compound to the known concentrations of the internal standard anthracene. The present method allows for a rapid and simple quantification of ephedrine alkaloid derivatives in Ephedra-related commercial prescriptions without any preliminary purification steps and standard compounds, and accordingly it can be a powerful tool to verify different Ephedra species. In comparison to conventional chromatographic methods, the advantages of this method include the fact that no standard compounds are required, the quantification can be directly performed on the crude extracts, a better selectivity for various ephedrine alkaloid derivatives, and the fact that a very significant time-gain may be achieved.

Nine prohibited stimulants found in sports and weight loss supplements: deterenol, phenpromethamine (Vonedrine), oxilofrine, octodrine, beta-methylphenylethylamine (BMPEA), 1,3-dimethylamylamine (1,3-DMAA), 1,4-dimethylamylamine (1,4-DMAA), 1,3-dimethylbutylamine (1,3-DMBA) and higenamine.

BACKGROUND: Weight loss and sports supplements containing deterenol have been associated with serious adverse events including cardiac arrest. OBJECTIVE: To determine the presence and quantity of experimental stimulants in dietary supplements labeled as containing deterenol sold in the United States. METHODS: Dietary supplements available for sale in the US and labeled as containing deterenol or one of its synonyms (e.g., isopropylnorsynephrine and isopropyloctopamine) were purchased online. For each brand, one container or subsample was analyzed by NSF International (Ann Arbor, MI) and one container or subsample by the Netherland's National Institute for Public Health and the Environment (RIVM, Bilthoven, The Netherlands). When differences existed between the two containers or subsamples of the same brand, both products were reanalyzed by Sciensano (Brussels, Belgium). NSF International carried out qualitative and quantitative analyses using ultra-high-performance liquid chromatography (UHPLC) quadrupole-Orbitrap mass spectrometry. RIVM performed qualitative and quantitative analysis using UHPLC quadrupole time-of-flight mass spectrometry. Sciensano carried out qualitative analysis using UHPLC quadrupole-Orbitrap mass spectrometry. RESULTS: Seventeen brands of supplements were analyzed. Many brands included more than one prohibited stimulant in the same product: 4 brands (24%, 4/17) included 2 stimulants, 2 (12%, 2/17) combined 3 stimulants, and 2 (12%, 2/17) combined 4 stimulants. The range of quantities per recommended serving size of the 9 stimulants detected were 2.7 mg to 17 mg of deterenol; 1.3 mg to 20 mg of phenpromethamine (Vonedrine); 5.7 mg to 92 mg of beta-methylphenylethylamine (BMPEA); 18 mg to 73 mg of octodrine; 18 mg to 55 mg of oxilofrine; 48 mg of higenamine; 17 mg of 1,3-dimethylamylamine (1,3-DMAA); 1.8 mg to 6.6 mg of 1,3-dimethylbutylamine (1,3-DMBA); and 5.3 mg of 1,4-dimethylamylamine (1,4-DMAA). CONCLUSION: Weight loss and sports supplements listing deterenol as an ingredient contained 9 prohibited stimulants and 8 different mixtures of stimulants, with as many as 4 experimental stimulants per product. These cocktails of stimulants have never been tested in humans and their safety is unknown.

Screening and evaluation of anti-SARS-CoV-2 components from Ephedra sinica by ACE2/CMC-HPLC-IT-TOF-MS approach.

Traditional Chinese medicines played an important role in the treatment of COVID-19 in 2020. Ephedra sinica, one of the major constituent herbs of multi-component herbal formula, has been widely used to treat COVID-19 in China. However, its active components are still unclear. The objectives of this study are to screen and evaluate active components from the traditional Chinese medicine Ephedra sinica for the treatment of COVID-19. In our study, we established an ACE2/CMC bioaffinity chromatography model, and then developed an ACE2/CMC-HPLC-IT-TOF-MS system for the active compounds screening and identification from Ephedra sinica extract. We performed molecular docking and surface plasmon resonance (SPR) assays to assess the binding characteristics (binding mode and KD value). We used CCK-8 staining to assess the toxicity of screened compounds, and also used SARS-CoV-2 pseudovirus to observe the viropexis effect of screened compounds in ACE2h cells. In this current work, one fraction was fished out, separated and identified as ephedrine (EP), pseudoephedrine (PEP), and methylephedrine (MEP). Binding assays showed that the three compounds could bind with ACE2 in a special way to some amino acid residues, similar to the way SARS-CoV-2 bound with ACE2. Additionally, the three compounds, especially EP, can inhibit the entrance of SARS-CoV-2 spike pseudovirus into ACE2h cells because they can reduce the entrance ratio of pseudovirus in the pseudovirus model. Overall, the ACE2/CMC-HPLC-IT-TOF-MS system was established and verified to be suitable for ACE2-targeted bioactive compound screening. EP, PEP, and MEP with ACE2-binding features were screened out from Ephedra sinica, and acted as blockers inhibiting SARS-CoV-2 spike pseudovirus entering ACE2h cells.

Localization of Major Ephedra Alkaloids in Whole Aerial Parts of Ephedrae Herba Using Direct Analysis in Real Time-Time of Flight-Mass Spectrometry.

Mass spectrometry-based molecular imaging has been utilized to map the spatial distribution of target metabolites in various matrixes. Among the diverse mass spectrometry techniques, matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) is the most popular for molecular imaging due to its powerful spatial resolution. This unparalleled high resolution, however, can paradoxically act as a bottleneck when the bio-imaging of large areas, such as a whole plant, is required. To address this issue and provide a more versatile tool for large scale bio-imaging, direct analysis in real-time-time of flight-mass spectrometry (DART-TOF-MS), an ambient ionization MS, was applied to whole plant bio-imaging of a medicinal plant, Ephedrae Herba. The whole aerial part of the plant was cut into 10-20 cm long pieces, and each part was further cut longitudinally to compare the contents of major ephedra alkaloids between the outer surface and inner part of the stem. Using optimized DART-TOF-MS conditions, molecular imaging of major ephedra alkaloids of the whole aerial part of a single plant was successfully achieved. The concentration of alkaloids analyzed in this study was found to be higher on the inner section than the outer surface of stems. Moreover, side branches, which are used in traditional medicine, represented a far higher concentration of alkaloids than the main stem. In terms of the spatial metabolic distribution, the contents of alkaloids gradually decreased towards the end of branch tips. In this study, a fast and simple macro-scale MS imaging of the whole plant was successfully developed using DART-TOF-MS. This application on the localization of secondary metabolites in whole plants can provide an area of new research using ambient ionization mass spectroscopy and an unprecedented macro-scale view of the biosynthesis and distribution of active components in medicinal plants.

Correlation study between the pharmacokinetics of seven main active ingredients of Mahuang decoction and its pharmacodynamics in asthmatic rats.

The aim of this study was to investigate the pharmacokinetics and pharmacodynamics of seven main active components of Mahuang decoction (MHD) and its time-concentration-effect relationship. The asthmatic rat model was established by the method of ovalbumin (OVA) sensttization. The plasma concentrations of ephedrine, pseudoephedrine, methylephedrine, amygdalin, liquiritin, cinnamic acid, glycyrrhizic acid in asthmatic model rat were investigated by a selective and rapid HPLC/MS-MS method. Simultaneously, the asthma-involved cytokines including leukotrienes B4 (LTB4), thromboxane B2 (TXB2), 6-Keto-Prostaglandin F1α (6-K-PGF1α) and histamine (HIS) levels in rat plasma were determined by using ELISA. A mathematics method was applied to assess the trend of percentage rate of change among different time intervals of the seven components. The sigmoid E max function was used to establish the PK-PD modeling of MHD. The results indicated that MHD could control or ameliorate asthma. There was a hysteresis between the peaked drug concentration and maximum therapeutic effect of MHD. The PK-PD curves of MHD showed clockwise or counter-clockwise hysteresis loop. In addition, amygdalin might exert a more significant influence on regulating cytokines levels in asthmatic rats among the seven components of MHD.

Ephedra alkaloid contents of Chinese herbal formulae sold in Taiwan.

Consumption of Ephedra alkaloids is prohibited in-competition by the World Anti-Doping Agency (WADA). In Taiwan, colds are often treated with Chinese herbal formulae containing Herba Ephedrae. We screened products sold in Taiwan and preliminarily assessed their relationships with WADA threshold violations. Fifty-six concentrated powder products, including 19 Chinese herbal formulae that contained Herba Ephedrae, were collected. The content of Ephedra alkaloids, namely ephedrine (E), methylephedrine (ME), norpseudoephedrine (NPE; cathine), pseudoephedrine (PE), and norephedrine (NE; phenylpropanolamine), was determined using a validated high-performance liquid chromatography method. The results revealed that the phenotypic indicators of the collected products, E/PE and E/total ratios, were 1.52-4.70 and 0.49-0.72, respectively, indicating that the Herba Ephedrae species in these products was probably E. sinica or E. equisetina, but not E. intermedia. The contents of E, ME, NPE, PE, and NE and the total alkaloid contents in the daily doses of the products were 0.45-34.97, 0.05-4.87, 0.04-3.61, 0.15-12.09, and 0.01-2.00 mg and 0.68-53.64 mg, respectively. The alkaloid contents followed a relatively consistent order (E > PE > ME ≈ NPE > NE), even for products from different manufacturers. We calculated that single doses of 50.0% and 3.6% of the products would result in the WADA thresholds of E and NPE being exceeded, respectively. Our data provide critical information for athletes and medical personnel, who should be wary of using complex Chinese herbal formulae in addition to over-the-counter products.

Ephedrine as a lead compound for the development of new DPP-IV inhibitors.

AIM: Extracts from Ephedra species have been reported to be effective as antidiabetics. A previous in silico study predicted that ephedrine and five ephedrine derivatives could contribute to the described antidiabetic effect of Ephedra extracts by inhibiting dipeptidyl peptidase IV (DPP-IV). Finding selective DPP-IV inhibitors is a current therapeutic strategy for Type 2 diabetes mellitus management. Therefore, the main aim of this work is to experimentally determine whether these alkaloids are DPP-IV inhibitors. Materials & methods: The DPP-IV inhibition of Ephedra's alkaloids was determined via a competitive-binding assay. Then, computational analyses were used in order to find out the protein-ligand interactions and to perform a lead optimization. RESULTS: Our results show that all six molecules are DPP-IV inhibitors, with IC50 ranging from 124 µM for ephedrine to 28 mM for N-methylpseudoephedrine. CONCLUSION: Further computational analysis shows how Ephedra's alkaloids could be used as promising lead molecules for designing more potent and selective DPP-IV inhibitors.

Distribution Analysis via Mass Spectrometry Imaging of Ephedrine in the Lungs of Rats Orally Administered the Japanese Kampo Medicine Maoto.

Maoto, a traditional Japanese Kampo medicine, has been used to treat various respiratory diseases, including respiratory infections and influenza. Ephedrine (EPD), the main ingredient in maoto, is also clinically used to treat respiratory diseases. However, the pharmacokinetics and distribution of EPD in the lungs after the administration of maoto have not been demonstrated. This study aimed to determine the concentrations, distribution, and pharmacokinetics of EPD and its precursor methylephedrine (MEPD) in the lungs of rats orally administered maoto (1 and 4 g/kg). We used liquid chromatography-electrospray ionization-tandem mass spectrometry to measure the ingredient concentrations. Both ingredients were detected in maoto-treated lung homogenates. Next, we examined the distribution of both ingredients in lung sections by using matrix-assisted laser desorption/ionization-mass spectrometry imaging, a powerful tool for the visualization of the distribution of biological molecules. The mass spectrometry imaging analysis detected only EPD and provided the first visual demonstration that EPD is distributed in the alveoli, bronchi, and bronchioles in the lungs of rats orally administered maoto (4 g/kg, three times at 2-h intervals). These results suggest that the pharmacological efficacy of maoto for the amelioration of respiratory symptoms is related to the distribution of EPD in the lung.

Pharmaceutical doses of the banned stimulant oxilofrine found in dietary supplements sold in the USA.

Oxilofrine (4-[1-hydroxy-2-(methylamino)propyl]phenol) is a pharmaceutical stimulant prescribed in dosages of 16 to 40 mg to stimulate the heart and increase blood pressure. It has never been approved for use in the USA as a prescription drug or as a dietary supplement. Several athletes, however, have been banned from sport for testing positive for oxilofrine and have claimed that they inadvertently consumed oxilofrine in sports supplements. Consumption of supplements containing oxilofrine may also pose serious health risks. For example, one brand of supplements containing oxilofrine has been linked to serious adverse events including vomiting, agitation, and cardiac arrest. We designed our study to determine the presence and quantity of oxilofrine in dietary supplements sold in the USA. A validated ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry method was developed for the identification and quantification of oxilofrine. The separation was achieved using a reversed phase column, mass spectrometry detection, and a water/acetonitrile gradient as the mobile phase. The presence of oxilofrine was confirmed using a reference standard. We analyzed 27 brands of supplements labelled as containing a synonym of oxilofrine ('methylsynephrine') and found that oxilofrine was present in 14 different brands (52%) at dosages ranging from 0.0003 to 75 mg per individual serving. Of the supplements containing oxilofrine, 43% (6/14) contained pharmaceutical or greater dosages of oxilofrine. Following instructions on the label, consumers could ingest as much as 250 mg of oxilofrine per day. The drug oxilofrine was found in pharmacological and greater dosages in supplements labelled as containing methylsynephrine. Copyright © 2016 John Wiley & Sons, Ltd.

Determination of the Metabolite of Ephedrine, 4-Hydroxyephedrine, by LC-MS-MS in Rat Urine and Its Application in Excretion Profiles After Oral Administration of Ephedra sinica Stapf and Processing Ephedra sinica Stapf.

This study aims to study the changes of metabolism of Ephedra sinica Stapf caused by processing. A sensitive and rapid high-performance liquid chromatographic tandem mass spectrometry (LC-MS-MS) method was developed for the quantitation of the major metabolite of ephedrine, 4-hydroxyephedrine, utilizing lidocaine as the internal standard in rat urine. Urine samples were precipitated with acetonitrile. Chromatographic separation was achieved on an Ultimate C18 analytical column. Detection was performed by a multiple reaction monitoring mode via an electrospray ionization source operating in the positive ionization mode. The method was linear over the concentration range of 0.05-1.0c for all components. The intra- and inter-day precision values were <13.2% and the deviations ranged from -8.4% to 7.5%. The recoveries at three levels were more than 66.2%. The fully validated method was used to study the pharmacokinetic profile of 4-hydroxyephedrine in rat urine to investigate the effects caused by processing.

Validated quantification method for five ephedrines in dietary supplements using LC-MS/MS: Application to 503 cases.

Ephedrines in dietary supplements can arise from herbs or illegal adulteration so a liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for separation and quantification of ephedrine, pseudoephedrine, norephedrine, norepseudoephedrine, and methyl-ephedrine, some of which are isomer pairs of pseudo-structures. This method includes liquid-liquid extraction of ephedrines from three typical dietary supplement matrices-solid, liquid, and oil-as well as liquid chromatographic separation. After liquid chromatographic separation, ephedrines are qualitatively and quantitatively analyzed using triple quadrupole mass spectrometry with positive electrospray ionization in multi-reaction monitoring (MRM) mode. Ephedrine recoveries in a solid matrix ranged from 53.3-91.5%, in a liquid matrix from 56.4-102.3%, and in an oil matrix from 51.7-01.2%. Linearity ranges were 10-1000ng/g in solid and oil matrix and 1-100ng/ml in liquid matrix. Accuracy was -11.5-16.3%. Intra-day and inter-day variation are less than 5.9% and 7.3%, respectively. Expanded uncertainty of quantification is less than 0.123ng/g in a solid matrix, less than 0.139ng/ml in a liquid matrix, and less than 0.158ng/g in an oil matrix. Data collected for more than 500 routine samples are presented and discussed.

Variability of Stimulant Levels in Nine Sports Supplements Over a 9-Month Period.

Many studies have found that some dietary supplement product labels do not accurately reflect the actual ingredients. However, studies have not been performed to determine if ingredients in the same dietary supplement product vary over time. The objective of this study was to assess the consistency of stimulant ingredients in popular sports supplements sold in the United States over a 9-month period. Three samples of nine popular sports supplements were purchased over the 9-month period. The 27 samples were analyzed for caffeine and several other stimulants (including adulterants). The identity and quantity of stimulants were compared with stimulants listed on the label and stimulants found at earlier time points to determine the variability in individual products over the 9-month period. The primary outcome measure was the variability of stimulant amounts in the products examined. Many supplements did not contain the same number and quantity of stimulants at all time points over the 9-month period. Caffeine content varied widely in five of the six caffeinated supplements compared with the initial measurement (-7% to +266%). In addition, the stimulants-synephrine, octopamine, cathine, ephedrine, pseudoephedrine, strychnine, and methylephedrine-occurred in variable amounts in eight of the nine products. The significance of these findings is uncertain: the sample size was insufficient to support statistical analysis. In our sample of nine popular sports supplements, the presence and quantity of stimulants varied over a 9-month period. However, future studies are warranted to determine if the variability found is significant and generalizable to other supplements.

Simultaneous quantification and pharmacokinetics of alkaloids in Herba Ephedrae-Radix Aconiti Lateralis extracts.

The combination of Herba Ephedrae (Mahuang in Chinese) and Radix Aconiti Lateralis (Fuzi in Chinese) is a classical preparation in traditional Chinese medicine and used for treating colds and rheumatic arthralgia. However, herbal medicines containing ephedrines and Aconitum alkaloids are strictly regulated because of the potential for adverse effects on the cardiovascular system and the central nervous system. We aimed to investigate the pharmacokinetics of 11 alkaloids in the Mahuang-Fuzi combination and single-herb extracts after oral administration in rats. The alkaloids were norephedrine, norpseudoephedrine, ephedrine, pseudoephedrine, methylephedrine, aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine and benzoylhypaconine. Simultaneous determination of the alkaloids, including two pairs of diastereomers, was achieved in 14.5 min by a simple, rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method. The separation was performed on a Zorbax SB-Aq column (100 mm × 2.1 mm, 3.5 µm) at a flow rate of 0.3 mL/min using acetonitrile-0.1% formic acid aqueous solution as the mobile phase. The validated method demonstrated adequate sensitivity, selectivity and process efficiency for the quantitative analysis of complex herbal components. Compared with single-herb extracts, alkaloids in plasma (except methylephedrine, benzoylmesaconine and benzoylhypaconine) showed slower elimination (the mean residence time or half-life was longer), although the maximum plasma concentration and area under the plasma concentration curve values decreased. Accumulation may occur with continuous drug intake. These results suggest that drug monitoring may be essential for the safe use of the Mahuang-Fuzi combination.

UPLC-MS/MS determination of ephedrine, methylephedrine, amygdalin and glycyrrhizic acid in Beagle plasma and its application to a pharmacokinetic study after oral administration of Ma Huang Tang.

An ultra performance liquid chromatography-mass spectrometric (UPLC-MS) method was developed to investigate the pharmacokinetic properties of ephedrine, methylephedrine, amygdalin, and glycyrrhizic acid after oral gavage of Ma Huang Tang (MHT) in Beagles. Beagle plasma samples were pretreated using liquid-liquid extraction, and chromatographic separation was performed on a C18 column using a linear gradient of water-formic acid mixture (0.1%). The pharmacokinetic parameters of ephedrine, methylephedrine, amygdalin, and glycyrrhizic acid from MHT in Beagles were quantitatively determined by UPLC with tandem mass detector. The qualitative detection of the four compounds was accomplished by selected ion monitoring in negative/positive ion modes electrospray ionization-mass spectrometry (ESI-MS). Detection was based on multiple reaction monitoring with the precursor-to-product ion transitions m/z 166.096-116.983 (ephedrine), m/z 179.034-146.087 (methylephedrine), m/z 456.351-323.074 (amygdalin), and m/z 821.606-351.062 (glycyrrhizic acid). The selectivity, sensitivity, linearity, accuracy, precision, extraction recovery, ion suppression, and stability were within the acceptable ranges. The method described was successfully applied to reveal the pharmacokinetic properties of ephedrine, methylephedrine, amygdalin, and glycyrrhizic acid after oral gavage of MHT in Beagles.

Rapid on-site detection of ephedrine and its analogues used as adulterants in slimming dietary supplements by TLC-SERS.

Ephedrine and its analogues are in the list of prohibited substance in adulteration to botanical dietary supplements (BDS) for their uncontrollable stimulating side effects. However, they were always adulterated illegally in BDS to promote losing weight. In order to avoid detection, various kinds of ephedrine analogues were added rather than ephedrine itself. This has brought about great difficulties in authentication of BDS. In this study, we put forward for the first time a method which combined thin-layer chromatography (TLC) and surface-enhanced Raman scattering (SERS) to directly identify trace adulterant. Ephedrine, pseudoephedrine, methylephedrine, and norephedrine were mixed and used in this method to develop an analytical model. As a result, the four analogues were separated efficiently in TLC analysis, and trace-components and low-background SERS detection was realized. The limit of detection (LOD) of the four analogues was 0.01 mg/mL. Eight common Raman peaks (△υ = 620, 1003, 1030, 1159, 1181, 1205, 1454, 1603 cm(-1)) were extracted experimentally and statistically to characterize the common feature of ephedrine analogues. A TLC-SERS method coupled with common-peak model was adopted to examine nine practical samples, two of which were found to be adulterated with ephedrine analogues. Identification results were then confirmed by UPLC-QTOF/MS analysis. The proposed method was simple, rapid, and accurate and can also be employed to trace adulterant identification even when there are no available reference derivatives on-site or unknown types of ephedrine analogues are adulterated.

Naturally occurring norephedrine oxazolidine derivatives in khat (Catha edulis).

Khat (Catha edulis Forsk.) is a perennial shrub whose young leaves are chewed for their psychostimulating and anorectic properties. The main active principles of khat are believed to be the phenylpropylamino alkaloids, primarily (-)-cathinone [(S)-α-aminopropiophenone], (+)-cathine [(1S)(2S)-norpseudoephedrine], and (-)-norephedrine [(1R)(2S)-norephedrine]. GC-MS analyses of young leaf extracts indicated the presence of two oxazolidine derivatives, 2,4-dimethyl-5-phenyloxazolidine and 4-methyl-2-(trans-1-pentenyl)-5-phenyloxazolidine. To ascertain the chemical identity of these compounds, we synthesized the putative compounds by condensation of norephedrine and acetaldehyde or trans-2-hexenal, respectively. Spectroscopic analyses (GC-MS, NMR) of the structures of these synthetic compounds showed them to have identical retention indexes and mass spectra characteristic to 2,4-dimethyl-5-phenyloxazolidine and 4-methyl-2-(trans-1-pentenyl)-5-phenyloxazolidine. Marked differences in the ratios between each of these two norephedrine oxazolidine derivatives and total phenylpropylamino alkaloids were found among thirteen different khat accessions further indicating polymorphism in alkaloid ratios and content in C. edulis.

[Determination of ephedrine hydrochloride, pseudoephedrine hydrochloride and methylephedrine hydrochloride in maxingshigan decoction by CE].

OBJECTIVE: To establish the method for determination of ephedrine hydrochloride, pseudoephedrine hydrochloride and methylephedrine hydrochloride in maxingshigan decoction by capillary electrophoresis. METHODS: The separation was performed on a fused silica capillary of 60 cm x 55 microcrpm ID (52 cm of effective length). 60 mmol/L NaB4O7 + 10% (V/V) CH3OH (pH 9.0) was selected as the running buffer. The separation voltage was 12 kV. The samples was injected by gravity (10 s, 15 cm). The detection wavelength was 210 nm and berberine hydrochloride was the internal standard. RESULTS: The linear range of determination for ephedrine hydrochloride, pseudoephedrine hydrochloride and methylephedrine hydrochloride were 20.0-160.0 microg/mL (r = 0.9999), 7.5-60.0 microg/mL (r = 0.9991) and 2.0-10.0 microg/mL (r = 0.9993). The average recoveries were 98.0%, 97.0% and 97.8%, the precisions of the method were 2.31%, 2.21% and 2.00% (n=6), respectively. CONCLUSION: The method is convenient, rapid and accurate for the quality control of maxingshigan decoction.

Comparison of contents of five ephedrine alkaloids in three official origins of Ephedra Herb in China by high-performance liquid chromatography.

In the present paper, a fast and economical HPLC method [on a Phenomenex Polar-RP column with a solution of (phosphoric acid:triethylamine:dibutylamine:water = 0.40:0.1:0.2:499.3) and methanol] is developed, and applied for the determination of norephedrine, norpseudoephedrine, ephedrine (E), pseudoephedrine (PE) and methylephedrine (ME) in 64 samples of three species from main habitats in China. Quantitation data showed that total alkaloid content in Ephedra equisetina Bge. (2.708 ± 0.642%) is higher than that in E. sinica Stapf. (1.365 ± 0.624%) and E. intermedia Schrenk et C. A. Mey. (1.537 ± 0.746%), but the range of total alkaloid content in each species is so wide that the ranges of the three species greatly overlap. The contents of E, PE and ME are different among the three species. The ratio E/total alkaloid content and ratio E/PE as well as E and ME contents can be used for identification of E. sinica, E. intermedia and E. equisetina from one another.

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.