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Marker Compounds (marker + compound)
Selected AbstractsN -Cyanomethyl- N -Methyl-1-(3,,4,-methylenedioxyphenyl)-2-propylamine: An MDMA Manufacturing By-ProductJOURNAL OF FORENSIC SCIENCES, Issue 5 2008Helen Salouros B.Sc. Abstract:, This paper describes the structural elucidation of a compound produced during the synthesis of 3,4-methylenedioxymethylamphetamine (MDMA) via the reductive amination of 3,4-methylenedioxyphenyl-2-propanone (3,4-MDP-2-P) with methylamine and sodium cyanoborohydride. The compound was isolated from MDMA by column chromatography, proton and carbon nuclear magnetic resonance spectroscopy, LC/mass spectrometry, and total synthesis were used to identify the compound as N -cyanomethyl- N -methyl-1-(3,,4,-methylenedioxyphenyl)-2-propylamine. This compound has been identified as a potential synthetic route marker for the reductive amination of 3,4-MDP-2-P with methylamine and sodium cyanoborohydride and as such it should prove valuable to forensic scientists engaged in profiling illicit drugs. Profiling MDMA can provide useful information to law enforcement agencies relating to synthetic route, precursor chemicals and reagents employed and may be used for comparative analyses of different drug seizures. This paper also describes the structural elucidation of the analogous methylamphetamine synthetic route marker compound, N -cyanomethyl- N -methyl-1-phenyl-2-propylamine, produced during the reductive amination of phenyl-2-propanone using methylamine and sodium cyanoborohydride. [source] Polycyclic aromatic hydrocarbons in smoked cheeseJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2008Marie Suchanová Abstract BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) represent a group of organic compounds containing two or more aromatic rings. Their control in the human food chain is required due to the mutagenic and carcinogenic potential, exhibited in vertebrates. In the present study, the occurrence of PAHs in 36 cheeses smoked by various processes was investigated. RESULTS: PAH concentrations (sum of 15 US EPA PAHs) found in samples smoked under controlled industrial conditions were at level 0.11 µg kg,1, whereas in ,home-made' cheeses, the PAH content was up to 10 times higher. A similar trend was observed for B[a]P, a marker compound representing carcinogenic PAHs. While its levels in commercial products prepared by controlled smoking technologies were close to the limit of quantification (0.03 µg kg,1); in household samples, the B[a]P content ranged from 0.6 to 0.9 µg kg,1. Significantly higher amounts of PAHs (up to three to six times) were found in surface layers as compared to internal parts of cheese. CONCLUSION: Although smoked cheese is a popular food, only several papers have focused on PAH levels in these products. This paper evaluates the contribution of different smoking technologies to PAH contamination of several cheeses and thus can help in a risk assessment associated with their consumption. Moreover, the study shows the concentration ratios of selected PAHs, from which the type of smoking technology can be indicated. The results obtained in this study also supported the suggestion of the EU Scientific Committee on Food to use benzo[a]pyrene as an indicator of the occurrence of higher-molecular mass PAHs. Copyright © 2008 Society of Chemical Industry [source] A 90 day repeated oral toxicity study on plantamajoside concentrate from Plantago asiaticaPHYTOTHERAPY RESEARCH, Issue 12 2007Byung-Gyu Park Abstract Plantago asiatica is distributed widely in East Asia. Since ancient times it has been used as a diuretic to treat acute urinary infections, and as an antiinflammatory, antiasthmatic, antioxidant, antibacterial, antihyperlipidemic and antihepatitis drug. The major compound, plantamajoside from P. asiatica, which is used as a marker compound in chemotaxonomic studies, was reported to have antibacterial activity, inhibition activity against cAMP phosphodiesterase and 5-lipoxygenase and antioxidant activity. However, there are no reports on the safety of plantamajoside. This study assessed the toxic effects of plantamajoside concentrate (PC), the purity of which was above 80%, in rats following administration at dose levels of 0, 500, 1000 and 2000 mg/kg body weight/day for 13 weeks, as recommended by the OECD guidelines. The results showed that there were no differences in body weight, food intake, water consumption, relative organ weight or the hematological and serum biochemical values among the different dosage groups. No death or abnormal clinical signs were observed during the experimental period. Therefore, the results suggested that no observed adverse effect level (NOAEL) of the PC in rats after oral administration is considered to be greater than 2000 mg/kg in rats under the conditions employed in this study. Copyright © 2007 John Wiley & Sons, Ltd. [source] Force propagation and force generation in cells,CYTOSKELETON, Issue 9 2010Oliver Jonas Abstract Determining how forces are produced by and propagated through the cytoskeleton (CSK) of the cell is of great interest as dynamic processes of the CSK are intimately correlated with many molecular signaling pathways. We are presenting a novel approach for integrating measurements on cell elasticity, transcellular force propagation, and cellular force generation to obtain a comprehensive description of dynamic and mechanical properties of the CSK under force loading. This approach uses a combination of scanning force microscopy (SFM) and Total Internal Reflection Fluorescence (TIRF) microscopy. We apply well-defined loading schemes onto the apical cell membrane of fibroblasts using the SFM and simultaneously use TIRF microscopy to image the topography of the basal cell membrane. The locally distinct changes of shape and depth of the cytoskeletal imprints onto the basal membrane are interpreted as results of force propagation through the cytoplasm. This observation provides evidence for the tensegrity model and demonstrates the usefulness of our approach that does not depend on potentially disturbing marker compounds. We confirm that the actin network greatly determines cell stiffness and represents the substrate that mediates force transduction through the cytoplasm of the cell. The latter is an essential feature of tensegrity. Most importantly, our new finding that, both intact actin and microtubule networks are required for enabling the cell to produce work, can only be understood within the framework of the tensegrity model. We also provide, for the first time, a direct measurement of the cell's mechanical power output under compression at two femtowatts. © 2010 Wiley-Liss, Inc. [source] Optimization and validation of a chromatographic method for the simultaneous quantification of six bioactive compounds in Rhizoma et Radix Polygoni CuspidatiJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2008Guangsheng Qian ABSTRACT A reverse-phase HPLC method was developed for simultaneous quantification of six bioactive compounds in Rhizoma et Radix Polygoni Cuspidati. These compounds , polydatin (1), resveratrol (2), rhein (3), emodin (4), chrysophanol (5) and physcion (6) , were analysed from 24 authentic samples of the herb using UV HPLC. Based on the UV absorption characteristics of the six compounds, absorption wavelengths of 306 nm were chosen to quantify compounds 1 and 2, and 290 nm for compounds 3,6. A reliable and reproducible quantitative HPLC method for analysing authentic samples of Rhizoma et Radix Polygoni Cuspidati from different cultivation regions was developed. The results showed that the concentration of compound 1 in samples from Sichuan was almost 2-fold higher than that of samples acquired in Guangxi. Furthermore, compounds 3 and 5 were not found in all the samples tested. Thus, instead of using polydatin (1) and emodin (4) as markers for quality assessment, as in conventional practice, these findings show that compounds 2 and 6 are more suited to act as marker compounds for a more specific assessment of the quality of this herb. [source] Comparative analysis of the chemical profile of wild and cultivated populations of Corydalis saxicola by high-performance liquid chromatographyPHYTOCHEMICAL ANALYSIS, Issue 5 2007Hui-liang Li Abstract Studies on the simultaneous determination and chemical fingerprinting of alkaloids in Corydalis saxicola Bunting. (Yanhuanglian) were performed for authentication purposes. Ninety samples prepared from different parts of C. saxicola, including whole plants, roots, stems, leaves and flowers, from wild and cultivated populations, were submitted to quantitative determination and fingerprint analysis. Five major alkaloids, namely, tetradehydroscoulerine, dehydroapocavidine, dehydroisoapocavidine, coptisine and dehydrocavidine, were quantitatively analysed by reversed-phase HPLC with acceptable recoveries (>98.2%). Chemical fingerprinting of C. saxicola was established and involved 11 markers. The results indicated that there were no obvious differences between the chemical profiles of wild and of cultivated C. saxicola populations, and that the mean alkaloid contents of the five marker compounds in cultivated populations were significantly higher than those of the wild plants. The highest content of total alkaloids (up to 28.8 mg/g) was found in roots of C. saxicola. The total alkaloids of the leaves were approximately 50% of those of roots, suggesting that the leaves may be employed as an alternative source of alkaloids. Chemical fingerprints and quantitative HPLC analysis will have a positive impact on the conservation and cultivation of this medicinal plant. Copyright © 2007 John Wiley & Sons, Ltd. [source] Flooding induced emissions of volatile signalling compounds in three tree species with differing waterlogging tolerancePLANT CELL & ENVIRONMENT, Issue 9 2010LUCIAN COPOLOVICI ABSTRACT To gain insight into variations in waterlogging responsiveness, net assimilation rate, stomatal conductance, emissions of isoprene and marker compounds of anoxic metabolism ethanol and acetaldehyde, and stress marker compounds nitric oxide (NO), volatile products of lipoxygenase (LOX) pathway and methanol were studied in seedlings of temperate deciduous tree species Alnus glutinosa, Populus tremula and Quercus rubra (from highest to lowest waterlogging tolerance) throughout sustained root zone waterlogging of up to three weeks. In all species, waterlogging initially resulted in reductions in net assimilation and stomatal conductance and enhanced emissions of ethanol, acetaldehyde, NO, LOX products and methanol, followed by full or partial recovery depending on process and species. Strong negative correlations between gs and internal NO concentration and NO flux, valid within and across species, were observed throughout the experiment. Isoprene emission capacity was not related to waterlogging tolerance. Less waterlogging tolerant species had greater reduction and smaller acclimation capacity in foliage physiological potentials, and larger emission bursts of volatile stress marker compounds. These data collectively provide encouraging evidence that emissions of volatile organics and NO can be used as quantitative measures of stress tolerance and acclimation kinetics in temperate trees. [source] Determination of the stable carbon isotopic compositions of 2-methyltetrols in ambient aerosols from the Changbai MountainsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2010Li Li Isoprene is one of the most important non-methane hydrocarbons (NMHCs) in the troposphere: it is a significant precursor of O3 and it affects the oxidative state of the atmosphere. The diastereoisomeric 2-methyltetrols, 2-methylthreitol and 2-methylerythritol, are marker compounds of the photooxidation products of atmospheric isoprene. In order to obtain valuable information on the ,13C value of isoprene in the atmosphere, the stable carbon isotopic compositions of the 2-methyltetrols in ambient aerosols were investigated. The 2-methyltetrols were extracted from filter samples and derivatized with methylboronic acid, and the ,13C values of the methylboronate derivatives were determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). The ,13C values of the 2-methyltetrols were then calculated through a simple mass balance equation between the 2-methyltetrols, methylboronic acid and the methylboronates. The ,13C values of the 2-methyltetrols in aerosol samples collected at the Changbai Mountain Nature Reserves in eastern China were found to be ,24.66,±,0.90, and ,24.53,±,1.08, for 2-methylerythritol and 2-methylthreitol, respectively. Based on the measured isotopic composition of the 2-methyltetrols, the average ,13C value of atmospheric isoprene is inferred to be close to or slightly heavier than ,24.66, at the collection site during the sampling period. Copyright © 2010 John Wiley & Sons, Ltd. [source] Quality assessment of Cortex Phellodendri by high-performance liquid chromatography coupled with electrospray ionization mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 4 2010Yong Mei Hu Abstract A simple method based on liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry (LC-DAD-ESI-MS) was developed for the quality assessment of Cortex Phellodendri (CP), which was mainly derived from two species of Phellodendron chinense Schneid and Phellodendron amurense Rupr. Total 41 compounds, including 14 phenols, 24 alkaloids and three liminoidal triterpenes were identified or tentatively characterized from the 75% methanol extract of CP samples by online ESI-MSn fragmentation and UV spectra analysis. Among them, two phenols and six alkaloids were simultaneously quantified using HPLC-DAD method. The validated HPLC-DAD method showed a good linearity, precision, repeatability and accuracy for the quantification of eight marker compounds. Furthermore, the plausible fragmentation pathway of the representative compounds were proposed in the present study. The differences of the chemical constituents content and the comprehensive HPLC profiles between the two CP species using LC-DAD-ESI-MS method are reported for the first time, indicating that the CP drugs from different resources should be used separately in the clinic. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||||||||