bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantification of reduced glutathione by HPLC‐UV in erythrocytes of hemodialysis patients
Authors: Garcia Solange Cristina , Schott Karen , Charão Mariele , Moro Angela , Bulcão Rachel , Grotto Denise , Valentini Juliana , Bohrer Denise , Cardoso Simone , Pomblum Valdeci 
Published: January 2008

AbstractReduced glutathione (GSH) is a well‐known multifunctional antioxidant. Its depletion is linked to a number of pathologies, such as renal insufficiency. Feasible methodologies in clinical chemistry are vital. Therefore a methodology for GSH quantification was optimized and validated by HPLC‐UV. Important aspects such as acid deproteinization and GSH stability were established. The erythrocytes were hemolyzed, deproteinized, derivatized with 5,5‐dithio‐bis (2‐nitrobenzoic) acid and analyzed using HPLC, on an RP18 gradient elution, λ = 330 nm. The method was applied to hemodialysis patients (n = 75) compared with healthy subjects (n = 40). The assay was linear from 0.5 to 3.0 mm (r2 > 0.99). The intra‐ and inter‐run reproducibilities were obtained with CV% < 10%. The accuracy (bias %) ranged from 1.32 to –6.38%, and the recovery was >94%. The derivatized sample was stable for 60 days at –20°C. The GSH levels in hemodialysis patients showed a significant increase compared with healthy subjects (p < 0.05) and an inverse correlation with age (r = –0.286; p = 0.013) was found. This method used UV detection, reduction of the phosphate concentration in the mobile phase and effective protein removal with trichloroacetic acid. The method proved to be reproducible, precise, accurate and stable. Thus, it can be suggested for routine laboratory tests for the verification of physiopathological conditions. Copyright © 2007 John Wiley & Sons, Ltd.
Correlation between the genetic diversity and variation of total phenolic acids contents in Fructus Xanthii from different populations in China
Authors: Han Ting , Hu Yuan , Zhou Shan‐Yong , Li Hui‐Liang , Zhang Qiao‐Yan , Zhang Hong , Huang Bao‐Kang , Rahman Khalid , Zheng Han‐Chen , Qin Lu‐Ping 
Published: January 2008

AbstractFructus Xanthii (Cang‐Er‐Zi) is a traditional Chinese medicine that is used in curing nasal diseases and headache according to the Chinese Pharmacopoeia. For the effective quality control of its medicinal values, reflected by chemical variation patterns, in addition to the relationship with genetic diversity, analyses based on UV spectrophotometry, HPLC fingerprinting and inter‐simple sequence repeat (ISSR) molecular markers were carried out, involving 16 Xanthium populations from different locations in China. The HPLC data showed considerable variation of chemical constituents among the 16 Xanthium populations, and they were classified to three chemotypes by hierarchical clustering analysis. Abundant genetic diversity was detected among the Xanthium populations, which were also clustered into three groups based on their ISSR data and varied according to different species. Combining the genetic divergence and chemical differences showed an important result that, in the two chemotypes, the higher contents of total phenolic acids (TPA) in Fructus Xanthii showed greater genetic diversity (I). We suggest that genetic diversity affects the contents of TPA. Since variable phenolic acid contents may affect therapeutic efficacy, it is important to point out that combining the use of genetic base with chemotype will help control the favourable chemotypes and breed new cultivars with more desirable chemical constituents. Copyright © 2007 John Wiley & Sons, Ltd.
Novel molecularly imprinted monolithic column for selective on‐line extraction of ciprofloxacin from human urine
Authors: Yan Hongyuan , Row Kyung Ho 
Published: January 2008

AbstractWater‐compatible ciprofloxacin‐imprinted monolithic columns were synthesized in water‐containing systems for selective extraction of ciprofloxacin from human urine samples. Methanol–water (10:3, v/v) was used as a porogenic solvent and the obtained monolithic imprinted polymers reveal high selectivity to ciprofloxacin in an aqueous environment; the affinity can be easily controlled by adjusting the pH of the mobile phase. Owing to the unique porous structure and flow‐through channels existing in the network skeleton of the monolithic MIP, urine samples could be directly injected into the column, proteins and other biological matrix were quickly washed out and ciprofloxacin was selectively retained and enriched. Good linearity was obtained from 0.08 to 400 mg/L (r = 0.998) with the relative standard deviations less than 3.6%. The limit of detection of the method was 0.04 mg/L and the recoveries were more than 94.5% at three different concentrations. Moreover, by increasing the injection volume to 2.0 mL, the sensitivity of the method could be improved 100‐fold according to the peak height of ciprofloxacin. This expedient greatly simplified the overall procedure, resulting in a rapid and efficient sample analysis while maintaining precision and accuracy. Copyright © 2007 John Wiley & Sons, Ltd.
Measurement of reduced and total mercaptamine in urine using liquid chromatography with ultraviolet detection
Authors: Kuśmierek Krzysztof , Bald Edward 
Published: January 2008

AbstractA simple liquid chromatographic method for the determination of reduced and total mercaptamine in human urine is described. The method is based on derivatization with 2‐chloro‐1‐methylquinolinium tetrafluoroborate followed by ion‐pairing reversed‐phase liquid chromatography separation and ultraviolet‐absorbance detection at 355 nm. Total mercaptamine was determined by reductive conversion of its oxidized fraction to the thiol form before the derivatization step. Baseline separation was achieved on an analytical Zorbax SB C18 (5 µm, 150 × 4.6 mm) column with a mobile phase consisting of pH 2.0 0.05 mol L−1 trichloroacetic acid buffer (component A) and acetonitrile (component B) pumped at 1.2 mL min−1. Gradient elution was used: 0–3 min 12% B, 3–9 min 12–30% B, 9–12 min 30–12% B. The response of the detector was linear within the ranges studied, from 0.1 to 50 µmol L−1 for reduced mercaptamine and from 0.4 to 400 µmol L−1 for total mercaptamine. The imprecision ranges for reduced and total mercaptamine were within 1.45–11.71 and 0.73–10.61%, respectively. The analytical accuracy for determined compounds was from 98.79 to 109.77%. The lower limits of detection and quantitation were 0.05 and 0.1 µmol L−1 of urine for reduced mercaptamine, and 0.2 and 0.4 µmol L−1 of urine for total mercaptamine, respectively. This method can be used for routine clinical monitoring of the title thiol‐drug and its reduced and oxidized fractions. Moreover, cysteine and cysteinylglycine can be measured concurrently, if needed. Copyright © 2007 John Wiley & Sons, Ltd.
Separation of different forms of proteose peptone 3 by hydrophobic interaction chromatography with a dual salt system
Authors: Sousa A. , Passarinha L. A. , Rodrigues L. R. , Teixeira J. A. , Mendonça A. , Queiroz J. A. 
Published: January 2008

AbstractA panel of four hydrophobic adsorbents (butyl‐, octyl‐, phenyl‐ and epoxy‐Sepharose) was used to examine the selectivity and fractionation of several proteose peptone 3 (PP3) forms from a freeze‐dried extract of whey bovine milk. In particular, the effects of altering the ligand type and salt were investigated. The chromatographic studies suggest that PP3 strongly interacts among the three commercial hydrophobic resins leading to a drop off in selectivity, while a complete binding was achieved at low salt concentrations (below 0.5 m) and total elution only with phosphate buffer and/or water stepwise conditions. Only in epoxy–Sepharose was an appreciably selectivity of the several fractions of PP3 present in the initial feedstock attained. Despite the high salt concentration for a complete binding of PP3 (above 1.5 m ammonium sulfate) onto this support, the dual salt system (ammonium sulfate 1 m and sodium citrate 0.8 m) led to a high separation degree of high and low molecular weight forms of PP3. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of lovastatin in human plasma by ultra‐performance liquid chromatography/electrospray ionization tandem mass spectrometry
Authors: Wang Dong , Wang Dongmei , Qin Feng , Chen Lingyun , Li Famei 
Published: January 2008

AbstractA fast and sensitive ultra‐performance liquid chromatography tandem mass spectrometry (UPLC‐MS/MS) method was developed for the determination of lovastatin in human plasma. With simvastatin as internal standard, sample pretreatment involved one‐step extraction with n‐hexane–methylene dichloride–isopropanol (20:10:1, v/v/v) of 0.5 mL plasma. Chromatographic separation was carried out on an Acquity™ UPLC BEH C18 column with mobile phase consisting of acetonitrile–water (containing 5 mmol/L ammonium acetate; 85:15, v/v) at a flow‐rate of 0.35 mL/min. The detection was performed on a triple‐quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) via electrospray ionization source with positive mode. The analysis time was shorter than 1.7 min per sample. The standard curve was linear (r2 ≥ 0.99) over the concentration range 0.025–50.0 ng/mL with a lower limit of quantification of 0.025 ng/mL. The intra‐ and inter‐day precision values were below 11% and the accuracy (relative error) was within 6.0% at three quality control levels. This is the first method of MS with MRM coupled to UPLC for the determination of lovastatin, which showed great advantages of high sensitivity, selectivity and high sample throughput. It was fully validated and successfully applied to the pharmacokinetic study of lovastatin tablets in healthy Chinese male volunteers after oral administration. Copyright © 2007 John Wiley & Sons, Ltd.
Optimization and validation of RP‐HPLC‐UV method with solid‐phase extraction for determination of buparvaquone in human and rabbit plasma: application to pharmacokinetic study
Authors: Venkatesh Gantala , Majid M. I. A. , Ramanathan S. , Mansor S. M. , Nair N. K. , Croft Simon L. , Navaratnam V. 
Published: January 2008

AbstractA simple, sensitive and specific reversed‐phase high‐performance liquid chromatographic method with UV detection at 251 nm was developed for quantitation of buparvaquone (BPQ) in human and rabbit plasma. The method utilizes 250 µL of plasma and sample preparation involves protein precipitation followed by solid‐phase extraction. The method was validated on a C18 column with mobile phase consisting of ammonium acetate buffer (0.02 m, pH 3.0) and acetonitrile in the ratio of 18:82 (v/v) at a flow rate of 1.1 mL/min. The calibration curves were linear (correlation coefficient ≥0.998) in the selected range. The method is specific and sensitive with limit of quantitation of 50 ng/mL for BPQ. The validated method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions and BPQ was found to be stable. Partial validation studies were carried out using rabbit plasma and intra‐ and inter‐day precision and accuracy were within 7%. This method is simple, reliable and can be routinely used for preclinical pharmacokinetic studies for BPQ. Copyright © 2007 John Wiley & Sons, Ltd.
A stereospecific high‐performance liquid chromatographic assay for the determination of ketoconazole enantiomers in rat plasma
Authors: Hamdy Dalia A. , Brocks Dion R. 
Published: January 2008

AbstractA stereospecific high‐performance liquid chromatographic assay was developed for the quantitation of ketoconazole enantiomers (KTZ) in rat plasma. After protein precipitation of 100 µL plasma using acetonitrile, a wash step was performed using hexane. The supernatant was removed and KTZ enantiomers and amiodarone, the internal standard, were extracted using liquid–liquid extraction with tert‐butyl methyl ether. After transfer and evaporation of the organic layer, the residue was reconstituted in mobile phase and injected into the HPLC through a chiral column. The mobile phase consisted of hexane:ethanol:2‐propanol with diethyl amine, pumped at 1.5 mL/min. All components eluted within 18 min. KTZ enantiomers were baseline resolved and peaks were symmetrical in appearance with no interferences. Calibration curves were linear over the range 62.5–5000 ng/mL of enantiomer. The intraday and interday CV% assessments were ≤19 and <13%, respectively, and mean error was <4% for both enantiomers. The lower limit of quantitation was 62.5 ng/mL for each enantiomer based on 100 µL rat plasma. In rats, plasma concentrations of (+)‐KTZ were higher than those of antipode after single oral doses. The assay was shown to be sensitive and appropriate for use in pharmacokinetics study of KTZ in rat. Copyright © 2008 John Wiley & Sons, Ltd.
Oxidative stress increases 6‐nitronorepinephrine and 6‐nitroepinephrine concentrations in rat brain
Authors: Tsunoda Makoto , Uchino Erika , Imai Kazuhiro , Funatsu Takashi 
Published: January 2008

Abstract6‐Nitronorepinephrine (nitroNE) and 6‐nitroepinephrine (nitroE) are reaction products of nitric oxide and norepinephrine and epinephrine, respectively. The authors have previously reported a method for determination of nitroNE and nitroE in rat brain using high‐performance liquid chromatography–peroxyoxalate chemiluminescence reaction detection. In this study, the effect of oxidative stress on nitroNE and nitroE concentrations in rat brain was examined using this method. After kainic acid administration in rats for 2 days, the concentrations of both nitroNE and nitroE in rat brains were found to have increased by 400–600%, which was partly suppressed by the co‐administration of a superoxide dismutase mimetic. This indicates that oxidative stress might increase nitroNE and nitroE concentrations in rat brains. Copyright © 2008 John Wiley & Sons, Ltd.
Development of extraction procedures for the determination of imidacloprid: application to residue analysis and dynamics of two formulations in Chinese cabbage
Authors: Khay Sathya , Abd El‐Aty A. M. , Cho Soon‐Kil , Choi Jeong‐Heui , Mamun M. I. R. , Goudah Ayman , Shin Ho‐Chul , Shim Jae‐Han 
Published: January 2008

AbstractThis study was undertaken to investigate whether an additional column clean‐up procedure can affect the accuracy of an analytical method developed for the determination of imidacloprid residues in Chinese cabbage. Thereafter, the residue levels and the degradation rates of imidacloprid were investigated in experimental Chinese cabbage plots after treatment with two different commercial formulations: emulsifiable concentrate (EC) and wettable powder (WP). The analyte was determined using high‐performance liquid chromatography–ultraviolet detection (HPLC‐UVD) and confirmed by high‐performance liquid chromatography–mass spectrometry (HPLC‐MS) in the select ion‐monitoring mode. The mean recoveries ranged from 75.34 to 98.00% and 96.95 to 100.97%, with relative standard deviations of 0.86–4.14 and 1.22–3.52%, in samples treated with and without additional column clean‐up procedures, respectively. The minimum detectable amount of imidacloprid was 4 ng, while the limits of detection and quantitation were 0.2 and 0.5 ppm, respectively. The degradation of pesticide was monitored throughout a period of 13 days under greenhouse conditions. Although the behaviors of the EC and WP formulations appear to be similar, the absolute residue levels obtained with EC and WP treatments differed slightly. When imidacloprid formulations were applied (as foliar treatments) according to the recommended rate, the final residues (13 days post‐treatment) in Chinese cabbage were much lower than the maximum residue limit (MRL = 3.5 ppm) established by the Korean Food and Drug Administration. Taken together, our study suggests that the analysis of imidacloprid can be performed without an additional column clean‐up procedure, and the decline curve and the residue levels in Chinese cabbage could change if the same active ingredient is used in different formulations. Copyright © 2008 John Wiley & Sons, Ltd.
Analysis of hairy root culture of Rauvolfia serpentina using direct analysis in real time mass spectrometric technique
Authors: Madhusudanan K. P. , Banerjee Suchitra , Khanuja Suman P. S. , Chattopadhyay Sunil K. 
Published: January 2008

AbstractThe applicability of a new mass spectrometric technique, DART (direct analysis in real time) has been studied in the analysis of the hairy root culture of Rauvolfia serpentina. The intact hairy roots were analyzed by holding them in the gap between the DART source and the mass spectrometer for measurements. Two nitrogen‐containing compounds, vomilenine and reserpine, were characterized from the analysis of the hairy roots almost instantaneously. The confirmation of the structures of the identified compounds was made through their accurate molecular formula determinations. This is the first report of the application of DART technique for the characterization of compounds that are expressed in the hairy root cultures of Rauvolfia serpentina. Moreover, this also constitutes the first report of expression of reserpine in the hairy root culture of Rauvolfia serpentina. Copyright © 2008 John Wiley & Sons, Ltd.
Chemical and Principal‐Component Analyses of the Essential Oils of Apioideae Taxa (Apiaceae) from Central Balkan
Authors: Kapetanos Chrysostomos , Karioti Anastasia , Bojović Srdjan , Marin Petar , Veljić Milan , Skaltsa Helen 
Published: January 2008

AbstractThe volatile constituents of the essential oils of 23 taxa belonging to the Apioideae subfamily were studied in detail. The investigated taxa were Pimpinella serbica (Vis.) Bentham & Hooker, Libanotis montana Cr., Cnidium silaifolium (Jacq.) Simk. ssp. orientale (Boiss.) Tutin, Bupleurum praealtum L., B. sibthorpianum S. S. var. diversifolium (Roch.) Hay, Aegopodium podagraria L., Torilis anthriscus (L.) Gmel., Orlaya grandiflora (L.) Hoffm., Laserpitium siler L., Laser trilobum (L.) Brokh., Chaerophyllum aureum L., C. hirsutum L., C. temulum L., Pastinaca sativa L., P. hirsuta Pancic., Tordylium maximum L., Physospermum cornubiense (L.) DC., Peucedanum alsaticum L., P. oreoselinum (L.) Moench, P. cervaria (L.) Cuss., P. austriacum (Jacq.) Koch, P. longifolium W. et K., and P. officinale L. All of these species grow wild in the central part of the Balkan Peninsula. The essential oils were found to be complex mixtures of various compounds, more than 100 constituents being in each taxon, with contributions of main products never exceeding 25% of the total content. Sesquiterpene hydrocarbons were found to be the main group of constituents of all taxa, except for Peucedanum species, where monoterpene hydrocarbons were identified as the main components. The chemotaxonomic value of the essential‐oil composition is discussed according to results of principal‐component analysis (PCA). The essential‐oil composition mainly reflects current taxonomic relationships between the investigated taxa.
Total Synthesis of Junionone, a Natural Monoterpenoid from Juniperus communis L., and Determination of the Absolute Configuration of the Naturally Occurring Enantiomer by ROA Spectroscopy
Authors: Lovchik Martin A. , Fráter Georg , Goeke Andreas , Hug Werner 
Published: January 2008

AbstractRecently, we reported a novel access to 2,2‐diethyl‐3‐[(E/Z)‐prop‐1‐en‐1‐yl]cyclobutanone by an intramolecular nucleophilic substitution with allylic rearrangement (SNi′) of (E)‐6‐chloro‐3,3‐diethylhept‐4‐en‐2‐one. The ring closure reaction was found to proceed with selective syn‐displacement of the leaving group. This method was now applied to the total synthesis of junionone, an olfactorily interesting cyclobutane monoterpenoid isolated from Juniperus communis, L. SNi′ Ring closure of the ketone enolate of (E)‐3,3‐dimethyl‐5‐[(2R,3R)‐3‐methyloxiran‐2‐yl]pent‐4‐en‐2‐one (R,R)‐(E)‐4′ proceeded only after the epoxide moiety had been activated by Lewis acid and led to the junionone precursors (3R)‐ and (3S)‐3‐[(1E,3R)‐3‐hydroxybut‐1‐en‐1‐yl]‐2,2‐dimethylcyclobutanone (S/R,R)‐(E)‐3. The ratio of syn‐ and anti‐conformers in the transitory molecular arrangement was found to depend on the nature of the Lewis acid. The absolute configuration of both the synthetic as well as the natural junionone, isolated from juniper berry oil, was determined by Raman Optical Activity (ROA) spectroscopy. Our experiments led to a novel synthetic route to both (+)‐ and (−)‐junionone, the first determination of the absolute configuration of natural junionone, and to the development of a practical ROA procedure for measuring milligram quantities of volatile liquids.
Synthesis and DNA‐Recognition and ‐Cleavage Properties of Multiply Charged Porphyrin Esters
Authors: Wu Lin , Hu Peng , Xiao Ying , Zhang Ming , Zhang Lixia , Weng Xiaocheng , Wu Xiaojun , Zhou Xiang , Cao Xiaoping 
Published: January 2008

AbstractA series of systematically modified porphyrin esters, compounds 1–6, with multiple, permanent positive charges introduced at the meso‐positions via N‐methylated 4‐, 3‐, or 2‐pyridyl moieties, were prepared and characterized. Their singlet‐oxygen production, CT‐DNA‐binding properties, and plasmid‐DNA photocleavage propensities were determined spectroscopically and by gel electrophoresis, and compared to those of the known, fourfold‐charged parent porphyrin 4,4′,4″,4′′′‐porphyrin‐5,10,15,20‐tetrayltetrakis(1‐methylpyridinium) (TMPyP4). Some interesting structure–activity relationships could be established to rationalize effects affecting DNA binding mode and cleavage ability.
New Bioactive Clerodane Diterpenoids from the Roots of Casearia membranacea
Authors: Chen Ching‐Yu , Cheng Yuan‐Bin , Chen Shun‐Ying , Chien Ching‐Te , Kuo Yao‐Haur , Guh Jih‐Hwa , Khalil Ashraf Taha , Shen Ya‐Ching 
Published: January 2008

AbstractBioassay‐guided fractionation of the acetone extract of the roots of Casearia membranacea furnished three new clerodane diterpenes, caseamembrins S–U (1–3) and the known caseamembrin Q (4). Their structures were established by extensive spectroscopic analyses, especially 2D‐NMR. Compounds 1–4 were tested against human tumor cells, including HeLa (cervical epitheloid carcinoma), DLD‐1 (colon carcinoma), Daoy (medulloblastoma), and KB (oral epidermoid carcinoma) cell lines. Caseamembrin T (2) exhibited the most potent activity against Daoy cells (ED50=10 ng/ml), superior to that of the standard drug mitomycin.
Variability in Essential‐Oil Composition of Piper marginatum sensu lato
Authors: Andrade Eloisa Helena A. , Carreira Léa Maria M. , da Silva Milton Helio L. , da Silva João Domingos , Bastos Cleber N. , Sousa Pergentino José C. , Guimarães Elsie F. , Maia José Guilherme S. 
Published: January 2008

AbstractThis paper contains data on the chemical composition of the essential oils of 22 leaf samples of Piper marginatum Jacq. collected in different areas and ecosystems of the brazilian Amazon, as well as an overview of the available literature. The species presents a large synonymy based on their different leaf characteristics and distinct scents where some of them smell like anise or very close compounds. By GC, GC/MS, and cluster analysis, we identified seven chemotypes for the leaf oils. The main components found in chemotype I were safrole (1) and 3,4‐(methylenedioxy)propiophenone (2). The chemotype II was dominated by 3,4‐(methylenedioxy)propiophenone (2) and p‐mentha‐1(7),8‐diene (10). The major compounds identified in chemotype III were 3,4‐(methylenedioxy)propiophenone (2), myristicin (3), (E)‐β‐ocimene (11), and γ‐terpinene (12). In the chemotype IV, the principal constituents were β‐caryophyllene (13), α‐copaene (14), and 3,4‐(methylenedioxy)propiophenone (2). The chemotype V was dominated by (E)‐isoosmorhizole (6), (E)‐anethole (8), and isoosmorhizole (7). The main compounds found in the chemotype VI were 2‐methoxy‐4,5‐(methylenedioxy)propiophenone (4), methoxy‐4,5‐(methylenedioxy)propiophenone isomer 5, and (E)‐isoosmorhizole (6). The major constituents in chemotype VII were β‐caryophyllene (13), bicyclogermacrene (15), and (E)‐asarone (9).