Identification of major xanthones and steroidal saponins in rat urine by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry technology following oral administration of Rhizoma Anemarrhenae decoction

Rhizoma Anemarrhenae (Zhimu in Chinese), the dried rhizome of Anemarrhena asphodeloides Bge. (Fam. Liliaceae), is a well-known traditional Chinese medicinal herb and has been used clinically in China for centuries to cure various diseases. However, like other traditional Chinese medicines, the effective constituents of this medicine, especially the assimilation and metabolites in vivo, which are very important to show their effects, have not been systematically studied. In this paper, solid-phase extraction and liquid chromatography-atmospheric pressure chemical ionization mass spectrometry technologies were used to study the constituents absorbed into rat urine and their metabolites after oral administration of Rhizoma Anemarrhenae decoction. A total of 11 compounds, including two xanthones, three of their metabolites and six steroidal saponins, were identified in rat urine sample. They were neomangiferin (1), glucuronide and monomethyl conjugate of mangiferin (2), mangiferin (3), monomethyl conjugate of mangiferin (4), dimethyl conjugate of mangiferin (5), timosaponin N or timosaponin E1 (6), timosaponin BII (7), timosaponin BIII (8), anemarrhenasaponin I or anemarrhenasaponin II (9), timosaponin AII (10) and timosaponin AIII (11). The results would efficaciously narrow the potentially active compounds range in Rhizoma Anemarrhenae decoction, and pave a helpful way for follow-up mechanism of action research.     

修饰丝网印刷电极的制备及抑郁小鼠大脑和血液样品中5-羟色胺含量的测定

制备了多壁碳纳米管和壳聚糖纳米复合材料(Multi-walled Carbon Nanotubes and Chitosan Nano-composites,MWCNTs-CHIN)修饰丝网印刷电极(MWCNTsCHIN/SPE),分别采用循环伏安法(CV)和方波伏安法(SWV)考察了5-HT在修饰丝网印刷电极上的电化学特性。在优化条件下,应用SWV法,5-羟色胺在0.30V处可产生灵敏的响应电流,且与其浓度呈线性,线性范围为0.01~1.00μmol/L,线性相关系数R为0.9969,检出限(S/N=3)为0.005μmol/L。用该方法测定慢性不可预见性应激抑郁模型(Chronic Unpredictable Mild Stress,CUMS)小鼠大脑和血液中5-HT的含量,结果表明,氟西汀组与空白组中5-HT的含量相当,模型组中5-HT的含量明显低于空白组(P0.01)。     

A novel ultra high‐performance liquid chromatography‐tandem mass spectrometry method for the simultaneous determination of xanthones and steroidal saponins in crude and salt‐processed Anemarrhenae Rhizoma aqueous extracts

We established a rapid and sensitive ultra high‐performance liquid chromatography tandem mass spectrometry method for the simultaneous quantification of xanthones and steroidal saponins in rat plasma. Chromatographic separation was achieved on a C₁₈ column with a mobile phase comprising acetonitrile and 0.1% formic acid. The detection was performed by negative electrospray ionization in multiple reaction monitoring mode. The validated method showed good linearity within the tested range (r > 0.9945). The intra‐ and interday precision at high, medium, and low concentrations was less than 7.96%. The bias of accuracies ranged from −1.92 to 9.62%. The extraction recoveries of the compounds ranged from 84.78 to 88.69%, and the matrix effects ranged from 96.76 to 108.59%. This method was successfully applied to a pharmacokinetic comparison of crude and salt‐processed Anemarrhenae Rhizoma aqueous extracts after oral administration in rats. The maximum plasma concentration and area under concentration–time curve of timosaponin BIII and timosaponin AIII increased significantly (P < 0.05 or 0.01) and those of timosaponin BII decreased significantly (P < 0.05) after processing. These results could contribute to the clinical application of crude and salt‐processed Anemarrhenae Rhizoma and reveal the processing mechanism.     

Metabolic analysis of the antidepressive effects of Yangxinshi Tablet in a vascular depression model in mice

In recent years, vascular depression has become the focus of international attention. Yangxinshi Tablet (YXST) is usually used in cthe linic for the treatment of arrhythmia and heart failure, but we found that it also has antidepressive effects. The objective of the study was to identify biomarkers related to vascular depression in hippocampus and explore the antidepressive effects of YXST on the mouse model. Untargeted metabolomics based on UHPLC‐Q‐TOF/MS was applied to identify significantly differential biomarkers between the model group and control group. Unsupervised principal component analysis (PCA) was used to scan the tendency of groups and partial least squares‐discriminant analysis (PLS‐DA) to distinguish between the vascular depressive mice and the sham. PCA stores showed clear differences in metabolism between the vascular depressive mice and sham groups. The PLS‐DA model exhibited 38 metabolites as the biomarkers to distinguish the vascular depressive mice and the sham. Further, YXST significantly regulated 22 metabolites to normal levels. The results suggested that YXST has a comprehensive antidepressive effect on vascular depression via regulation of multiple metabolic pathways including amino acid, the tricarboxylic acid cycle and phosphoglyceride metabolisms. These findings provide insight into the pathophysiological mechanism underlying vascular depression and the mechanism of YXST.     

Effects of the Bark Resin Extract of Garcinia nigrolineata on Chronic Stress-Induced Memory Deficit in Mice Model and the In Vitro Monoamine Oxidases and β-Amyloid Aggregation Inhibitory Activities of Its Prenylated Xanthone Constituents

The present study describes investigation of the effects of the bark resin extract of Garcinia nigrolineata (Clusiaceae) on the cognitive function and the induction of oxidative stress in both frontal cortex and hippocampus by unpredictable chronic mild stress (UCMS). By using behavioral mouse models, i.e., the Y-maze test, the Novel Object Recognition Test (NORT), and the Morris Water Maze Test (MWMT), it was found that the negative impact of repeated mild stress-induced learning and memory deficit through brain oxidative stress in the UCMS mice was reversed by treatment with the bark resin extract G. nigrolineata. Moreover, the prenylated xanthones viz. cowagarcinone C, cowaxanthone, α-mangostin, cowaxanthone B, cowanin, fuscaxanthone A, fuscaxanthone B, xanthochymusxanthones A, 7-O-methylgarcinone E, and cowagarcinone A, isolated from the bark resin of G. nigrolineata, were assayed for their inhibitory activities against β-amyloid (Aβ) aggregation and monoamine oxidase enzymes (MAOs).     

超高效液相色谱-串联质谱法定性和高效液相色谱法定量分析天南星中氨基酸成分

为建立中药材中氨基类极性非紫外活性成分的定性与定量分析方法,以中药材天南星为研究对象,采用柱前衍生化技术,以异硫氰酸苯酯(PITC)为衍生化试剂,经C₁₈色谱柱(100 mm×2.1 mm, 3.5 μm)分离和超高效液相色谱-串联质谱(UHPLC-MS/MS)分析,共解析了天南星中20个成分,包括18个氨基酸和2个胺类化合物。经优化衍生化条件,应用高效液相色谱法(HPLC),以Diamonsil C₁₈色谱柱(250 mm×4.6 mm, 5 μm)分离,以乙腈和0.05 mol/L醋酸铵-醋酸缓冲液(pH 6.5)为流动相,梯度洗脱,在254 nm下检测,建立了同时测定15种氨基酸含量的方法,经方法学考察符合含量测定要求。谷氨酸、色氨酸在2~100 mg/L范围内、精氨酸在6~300 mg/L范围内、其余各氨基酸在0.8~40 mg/L范围内均呈良好的线性关系,相关系数均不小于0.9995;平均回收率在95%~105%之间,RSD均小于3%;并成功应用于12批中药材的测定。本方法简便、灵敏、准确,具有可操作性,可用于快速鉴定中药中的氨基类成分以及进行含量测定。     

Simultaneous determination of senkyunolide I and senkyunolide H in rat plasma by LC‐MS: application to a comparative pharmacokinetic study in normal and migrainous rats after oral administration of Chuanxiong Rhizoma extract

A selective liquid chromatographic–mass spectrometric method has been developed and validated for simultaneous determination of senkyunolide I (SEI) and senkyunolide H (SEH) from Chuanxiong Rhizoma in rat plasma. Plasma samples were extracted by liquid–liquid extraction with ethyl acetate and separated on a Kromasil C₁₈ column (250 × 4.6 mm, 5 µm), with methanol–water (55:45, v/v) as mobile phase. The linear range was 0.05–25 µg/mL for SEI and 0.01–5.0 µg/mL for SEH, with lower limits of quantitation of 0.05 and 0.01 µg/mL, respectively. Intra‐ and inter‐day precision were within 10.0 and 9.8%, and the accuracies (relative errors) were <9.6 and 5.9%, with the mean extraction recoveries 81.0–86.6 and 80.5–85.0% for the two anayltes, respectively. The validated method was successfully applied to a comparative pharmacokinetic study of SEI and SEH in normal and migrainous rats after oral administration of Chuanxiong Rhizoma extract. The results indicated that there were obvious differences between normal and migrainous rats in the pharmacokinetic behavior after oral administration of Chuanxiong Rhizoma extract. The absorption of SEI and SEH were significantly increased in migrainous rats compared with normal rats. Copyright © 2015 John Wiley & Sons, Ltd.     

Simultaneous determination of atractylenolide II and atractylenolide III by liquid chromatography-tandem mass spectrometry in rat plasma and its application in a pharmacokinetic study after oral administration of Atractylodes Macrocephala Rhizoma extract

Atractylenolide II (AII) and atractylenolide III (AIII) are the major active components in Atractylodes Macrocephala Rhizoma (AMR). In this study, a sensitive, rapid and selective liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method was developed and validated for the simultaneous determination of AII and AIII in rat plasma using loliolide as internal standard (IS). After protein precipitation with ethyl acetate, the analytes were injected into an LC‐MS/MS system for quantification. Chromatography was performed using a C₁₈ column, eluting with water and acetonitrile (45:55, v/v) at 0.2 mL/min. All analytes including IS were monitored under positive ionization conditions by multiple reaction monitoring with an electrospray ionization source. The validated method was successfully applied to the pharmacokinetic study of AII and AIII in rat plasma after oral administration of AMR extract. The results provided a meaningful basis for evaluating the clinical applications of traditional Chinese medicine. Copyright © 2012 John Wiley & Sons, Ltd.     

Application of a crystallization kinetics model to simulate the effect of operation conditions on Crystaf profiles and calibration curves

Crystallization analysis fractionation (Crystaf) is a polymer characterization technique used to estimate chemical composition distributions (CCDs) of semicrystalline copolymers. The Crystaf profile can be transformed into a CCD using a calibration curve that relates average comonomer content to peak crystallization temperature. The calibration curve depends on copolymer molecular properties and Crystaf operation conditions. In this investigation, we applied a crystallization kinetics model to simulate Crystaf calibration curves and to quantify how Crystaf calibration curves depend on these factors. We applied the model to estimate the CCDs of three ethylene/1‐hexene copolymers from Crystaf profiles measured at different cooling rates and showed that our predictions agree well with the CCDs described by Stockmayer's distribution. We have also used this new methodology to investigate the effects of cooling rate, molecular weight, and comonomer type on Crystaf profiles and calibration curves. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 866–876, 2009     

Liquid chromatography mass spectrometry for the determination of salvianolic acid B,a natural compound from the herb Danshen in rat plasma and application to pharmacokinetic study

A sensitive and specific liquid chromatographic–electrospray ionization mass spectrometric method was developed for quantification of salvianolic acid B in rat plasma with resveratrol as the internal standard. The analytes were separated on a reversed‐phase column with acetonitrile (40%) and water (60%) containing 0.75% formic acid as mobile phase at a flow rate of 1 mL/min. Liquid–liquid extraction was adopted for the sample preparation, and the analytes were determined using electrospray negative ionization mass spectrometry in the selective monitoring mode. The method was validated over the concentration range 0.1–40 µg/mL using 0.1 mL of plasma with coefficients of correlation >0.999. The intra‐ and inter‐day precisions of analysis were <10%, and accuracy ranged from 94 to 101%. This method was successfully applied to a pharmacokinetics of salvianolic acid B in rats. Copyright © 2009 John Wiley & Sons, Ltd.     

Development of a molecularly imprinted polymer for selective extraction followed by liquid chromatographic determination of sitagliptin in rat plasma and urine

A novel water-compatible molecularly imprinted solid-phase extraction (MISPE) combined with zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) method for selective extraction and determination of sitagliptin in rat serum and urine was developed and validated. The effects of progenic solvents, pH, cross linker and amount of monomer were studied to optimize the efficiency and selectivity. The adsorption kinetics and isotherms were measured. The molecularly imprinted polymer (MIP) showed good specific adsorption capacity with an optimum of 180 mg/g at pH 7.5 and selective extraction of sitagliptin from rat plasma and urine. The recovery of sitagliptin from rat urine and plasma was >98%. The limits of detection (LOD) and quantification (LOQ) were 0.03 and 0.10 μg/L respectively. The proposed method overcomes the matrix effects of phospholipids generally encountered while preparation of plasma samples by precipitation of proteins.     

AES depth profiling with a tilted sample in front of a cylindrical mirror analyzer: quantification and profile shape changes according to an extension of the conventional MRI model

The influence of the tilt angle of a sample in front of a cylindrical mirror analyzer (CMA) on AES depth profiles is calculated with the conventional mixing‐roughness‐information (MRI) depth model and an extended MRI model. While the conventional model works with an average electron escape depth value, the extended model takes into account the intensity from different segments along the azimuth angle corresponding to different escape depth values before summing up for the total, measured intensity. The deviation between both approaches is generally less than 4%, even for the worst case at 47.7° tilt angle. The shape of the profile is slightly different for both approaches. Because, for a CMA with coaxial gun, the sample tilt angle varies as the electron beam incidence angle, the influence of the latter has to be additionally taken into account for quantification of AES. In reasonable agreement with experimental results it is shown that above 45° the Auger peak intensity of Cu (914 eV) increases up to about a factor of two for an incidence angle of 85°. Copyright © 2006 John Wiley & Sons, Ltd.     

Development of a liquid chromatography–tandem mass spectrometry method for the determination of Grayanotoxins in rat blood and its application to toxicokinetic study

A sensitive and specific high‐performance liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method was developed for the determination of Grayanotoxin I (GTX I) and Grayanotoxin III (GTX III) in rat whole blood. Grayanotoxins (GTXs) and clindamycin as internal standard (IS) were extracted from rat blood via solid‐phase extraction using PEP solid‐phase extraction cartridges. Chromatographic separation of the analytes was achieved on a Kinetex C₁₈ (100 × 2.1 mm, 2.6 µm) reversed‐phase column using a gradient elution with the mobile phase of 1% acetic acid in water and methanol at a flow rate of 0.2 mL/min. Electrospray ionization mass spectrometry was operated in the positive ion mode with multiple reaction monitoring. The calibration curves obtained were linear over the concentration range of 1–100 ng/mL with a lower limit of quantification of 1 ng/mL for GTXs. The relative standard deviation of intra‐day and inter‐day precision was below 6.8% and accuracy ranged from 94.8 to 106.6%. The analytes were stable in the stability studies. The validated method was successfully applied to the quantification and toxicokinetic study of GTXs in rats for the first time after oral administration of 11.52 mg/kg mad honey and 0.35 mg/kg GTX III, respectively. Copyright © 2014 John Wiley & Sons, Ltd.     

Hydrolysis of Nb(V) and Ta(V) in aqueous KCl at 25°C. Part II: Construction of a thermodynamic model for Ta(V)

In this work the hydrolysis of Ta(V) in 3.0M KCl has been studied by measuring the H₃O⁺ ion concentration with a glass electrode. The experimental work consisted of automatically controlled potentiometric titrations. The results were treated using graphical and numerical methods and, as a result, the hydrolysis process can be considered as a homonuclear protolysis. Finally, the results obtained were compared with other data found in the literature and a hydrolysis model for Ta(V) was built by means of the modified Bromley theory.     

Development and validation of an LC‐MS/MS method for the determination of a novel thienoquinolin urea transporter inhibitor PU‐48 in rat plasma and its application to a pharmacokinetic study

A specific, sensitive and stable high‐performance liquid chromatographic–tandem mass spectrometry (LC‐MS/MS) method was developed and validated for the quantitative determination of methyl 3‐amino‐6‐methoxythieno [2,3‐b]quinoline‐2‐carboxylate (PU‐48), a novel diuretic thienoquinolin urea transporter inhibitor in rat plasma. In this method, the chromatographic separation of PU‐48 was achieved with a reversed‐phase C₁₈ column (100 × 2.1 mm, 3 μm) at 35°C. The mobile phase consisted of acetonitrile and water with 0.05% formic acid added with a gradient elution at flow rate of 0.3 mL/min. Samples were detected with the triple‐quadrupole tandem mass spectrometer with multiple reaction monitoring mode via electrospray ionization source in positive mode. The retention time were 6.2 min for PU‐48 and 7.2 min for megestrol acetate (internal standard, IS). The monitored ion transitions were mass‐to‐charge ratio (m/z) 289.1 → 229.2 for PU‐48 and m/z 385.3 → 267.1 for the internal standard. The calibration curve for PU‐48 was linear over the concentration range of 0.1–1000 ng/mL (r² > 0.99), and the lower limit of quantitation was 0.1 ng/mL. The precision, accuracy and stability of the method were validated adequately. The developed and validated method was successfully applied to the pharmacokinetic study of PU‐48 in rats.