Searching for synergistic calcium antagonists and novel therapeutic regimens for coronary heart disease therapy from a Traditional Chinese Medicine, Suxiao Jiuxin Pill

Publication date: 15 August 2018 Source:Journal of Chromatography B, Volume 1092 Author(s): Wei Lei, Jianan Ni, Xueting Xia, Min Jiang, Gang Bai Coronary heart disease is a vital cause of morbidity and mortality worldwide, an…

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Wei Lei, Jianan Ni, Xueting Xia, Min Jiang, Gang Bai

Coronary heart disease is a vital cause of morbidity and mortality worldwide, and calcium channel blockers (CCBs) are important drugs that can be used to treat cardiovascular diseases. Suxiao Jiuxin Pill (SX), a traditional Chinese medicine, is widely used as an emergency drug for coronary heart disease therapy. However, understanding its potential mechanism in intracellular calcium concentration ([Ca2+]i) modulation remains a challenge. To identify the active pharmacological ingredients (APIs) and reveal a novel combination therapy for ameliorating cardiovascular diseases, the ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) combined with a dual-luciferase reporter [Ca2+]i assay system was applied. Ligustrazine, ferulic acid, senkyunolide I, senkyunolide A and ligustilide were identified as potential calcium antagonists in SX, and the combination of ligustrazine and senkyunolide A showed synergetic calcium antagonistic activity. Additionally, the synergetic mechanism was further investigated by live-imaging analysis with the Ca2+ indicator fluo-4/AM by monitoring fluorescence changes. Our results indicated that ligustrazine can block voltage-operated Ca2+ channels (VDCCs) effectively and senkyunolide A can exert an inhibition effect mostly on ryanodine receptors (RYRs) and partly on VDCCs. Finally, an arterial ring assay showed that the combination of ligustrazine and senkyunolide A exerted a better vasodilatation function than using any components alone. In this study, we first revealed that a pair of natural APIs in combination acting on VDCCs and RYRs was more effective on vasodilatation by regulating [Ca2+]i.





A new high-performance thin-layer chromatographic method for determining bile salt hydrolase activity

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Nur Syakila Rohawi, Kalavathy Ramasamy, Snezana Agatonovic-Kustrin, Siong Meng Lim
A quantitative assay using high-performance thin-layer chromatography (HPTLC) was developed to investigate bile salt hydrolase (BSH) activity in Pediococcus pentosaceus LAB6 and Lactobacillus plantarum LAB12 probiotic bacteria isolated from Malaysian fermented food. Lactic acid bacteria (LAB) were cultured in de Man Rogosa and Sharpe (MRS) broth containing 1 mmol/L of sodium-based glyco- and tauro-conjugated bile salts for 24 h. The cultures were centrifuged and the resultant cell free supernatant was subjected to chromatographic separation on a HPTLC plate. Conjugated bile salts were quantified by densitometric scans at 550 nm and results were compared to digital image analysis of chromatographic plates after derivatisation with anisaldehyde/sulfuric acid. Standard curves for bile salts determination with both methods show good linearity with high coefficient of determination (R2) between 0.97 and 0.99. Method validation indicates good sensitivity with low relative standard deviation (RSD) (<10%), low limits of detection (LOD) of 0.4 versus 0.2 μg and limit of quantification (LOQ) of 1.4 versus 0.7 μg, for densitometric vs digital image analysis method, respectively. The bile salt hydrolase activity was found to be higher against glyco- than tauro-conjugated bile salts (LAB6; 100% vs >38%: LAB12; 100% vs >75%). The present findings strongly show that quantitative analysis via digitally-enhanced HPTLC offers a rapid quantitative analysis for deconjugation of bile salts by probiotics.

Graphical abstract

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Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Nur Syakila Rohawi, Kalavathy Ramasamy, Snezana Agatonovic-Kustrin, Siong Meng Lim

A quantitative assay using high-performance thin-layer chromatography (HPTLC) was developed to investigate bile salt hydrolase (BSH) activity in Pediococcus pentosaceus LAB6 and Lactobacillus plantarum LAB12 probiotic bacteria isolated from Malaysian fermented food. Lactic acid bacteria (LAB) were cultured in de Man Rogosa and Sharpe (MRS) broth containing 1 mmol/L of sodium-based glyco- and tauro-conjugated bile salts for 24 h. The cultures were centrifuged and the resultant cell free supernatant was subjected to chromatographic separation on a HPTLC plate. Conjugated bile salts were quantified by densitometric scans at 550 nm and results were compared to digital image analysis of chromatographic plates after derivatisation with anisaldehyde/sulfuric acid. Standard curves for bile salts determination with both methods show good linearity with high coefficient of determination (R 2 ) between 0.97 and 0.99. Method validation indicates good sensitivity with low relative standard deviation (RSD) (<10%), low limits of detection (LOD) of 0.4 versus 0.2 μg and limit of quantification (LOQ) of 1.4 versus 0.7 μg, for densitometric vs digital image analysis method, respectively. The bile salt hydrolase activity was found to be higher against glyco- than tauro-conjugated bile salts (LAB6; 100% vs >38%: LAB12; 100% vs >75%). The present findings strongly show that quantitative analysis via digitally-enhanced HPTLC offers a rapid quantitative analysis for deconjugation of bile salts by probiotics.

Graphical abstract

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A novel strategy for isolation and determination of sugars and sugar alcohols from conifers

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): B.A. Sarvin, A.P. Seregin, O.A. Shpigun, I.A. Rodin, A.N. Stavrianidi
The ultrasound-assisted extraction method for isolation of 17 sugars and sugar alcohols from conifers with a subsequent hydrophilic interaction liquid chromatography-tandem mass spectrometry method for their determination is proposed. The optimization of extraction parameters was carried out using Taguchi – L9 (34) orthogonal array experimental design for the following parameters—a methanol concentration in the extraction solution, an extraction time, a type of plant sample and an extraction temperature. The optimal ultrasound-assisted extraction conditions were—MeOH concentration – 30% (water – 70%), extraction time – 30 min, type of plant sample – II (grinded leaves 2–4 mm long), extraction temperature – 60 °C. Pure water and acetonitrile were used as eluents in gradient elution mode to separate the analytes. Direct determination of multiple sugars and sugar alcohols was carried out using a mass spectrometric detector operated in a multiple reaction monitoring mode, providing detection limits in the range between 0.1 and 20 ng/mL and good analytical characteristics of the method without derivatization. The developed approach was validated by multiple successive extraction method applied to test its performance on a series of 10 samples, i.e. 2 samples per each of 5 genera: Abies, Larix, Picea, Pinus (Pinaceae) and Juniperus (Cupressaceae), widely distributed in the boreal conifer forests of Eurasia. The novel strategy can be used for profiling of sugars and sugar alcohols in a wide range of plant species.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): B.A. Sarvin, A.P. Seregin, O.A. Shpigun, I.A. Rodin, A.N. Stavrianidi

The ultrasound-assisted extraction method for isolation of 17 sugars and sugar alcohols from conifers with a subsequent hydrophilic interaction liquid chromatography-tandem mass spectrometry method for their determination is proposed. The optimization of extraction parameters was carried out using Taguchi – L9 (34) orthogonal array experimental design for the following parameters—a methanol concentration in the extraction solution, an extraction time, a type of plant sample and an extraction temperature. The optimal ultrasound-assisted extraction conditions were—MeOH concentration – 30% (water – 70%), extraction time – 30 min, type of plant sample – II (grinded leaves 2–4 mm long), extraction temperature – 60 °C. Pure water and acetonitrile were used as eluents in gradient elution mode to separate the analytes. Direct determination of multiple sugars and sugar alcohols was carried out using a mass spectrometric detector operated in a multiple reaction monitoring mode, providing detection limits in the range between 0.1 and 20 ng/mL and good analytical characteristics of the method without derivatization. The developed approach was validated by multiple successive extraction method applied to test its performance on a series of 10 samples, i.e. 2 samples per each of 5 genera: Abies, Larix, Picea, Pinus (Pinaceae) and Juniperus (Cupressaceae), widely distributed in the boreal conifer forests of Eurasia. The novel strategy can be used for profiling of sugars and sugar alcohols in a wide range of plant species.





Determination of aflatoxin and zearalenone analogs in edible and medicinal herbs using a group-specific immunoaffinity column coupled to ultra-high-performance liquid chromatography with tandem mass spectrometry

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Shujuan Sun, Kai Yao, Sijun Zhao, Pimiao Zheng, Sihan Wang, Yuyang Zeng, Demei Liang, Yuebin Ke, Haiyang Jiang
Six aflatoxins (AFs; AF B1, B2, G1, G2, M1 and M2) and six zearalenone (ZEN) analogs (ZEN, zearalanone, α-zeralanol, β-zeralanol, α-zearalenol, and β-zearalenol) were simultaneously extracted from edible and medicinal herbs using a group-specific immunoaffinity column (IAC) and then identified by ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS). The IAC was prepared by coupling N-hydroxysuccinimide-activated Sepharose 4B Fast Flow gel with two group-specific monoclonal antibodies. The column capacities to six AFs and six ZEN analogs ranged from 100.2 ng to 167.1 ng and from 59.5 ng to 244.4 ng, respectively. The IAC–UPLC–MS/MS method was developed and validated with three different matrices (Chinese yam [Dioscorea polystachya], Platycodon grandiflorum and coix seed [Semen Coicis]). Recoveries of twelve analytes from edible and medicinal herbs were in the range of 64.7%–112.1%, with relative standard deviations below 13.7%. The limits of quantification were in the range from 0.08 μg kg−1 to 0.2 μg kg−1. The method was proven to be sensitive and accurate, and suitable for the determination of real samples.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Shujuan Sun, Kai Yao, Sijun Zhao, Pimiao Zheng, Sihan Wang, Yuyang Zeng, Demei Liang, Yuebin Ke, Haiyang Jiang

Six aflatoxins (AFs; AF B1, B2, G1, G2, M1 and M2) and six zearalenone (ZEN) analogs (ZEN, zearalanone, α-zeralanol, β-zeralanol, α-zearalenol, and β-zearalenol) were simultaneously extracted from edible and medicinal herbs using a group-specific immunoaffinity column (IAC) and then identified by ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS). The IAC was prepared by coupling N-hydroxysuccinimide-activated Sepharose 4B Fast Flow gel with two group-specific monoclonal antibodies. The column capacities to six AFs and six ZEN analogs ranged from 100.2 ng to 167.1 ng and from 59.5 ng to 244.4 ng, respectively. The IAC–UPLC–MS/MS method was developed and validated with three different matrices (Chinese yam [Dioscorea polystachya], Platycodon grandiflorum and coix seed [Semen Coicis]). Recoveries of twelve analytes from edible and medicinal herbs were in the range of 64.7%–112.1%, with relative standard deviations below 13.7%. The limits of quantification were in the range from 0.08 μg kg−1 to 0.2 μg kg−1. The method was proven to be sensitive and accurate, and suitable for the determination of real samples.





Multivariate analytics of chromatographic data: Visual computing based on moving window factor models

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Valentin Steinwandter, Michal Šišmiš, Patrick Sagmeister, Ulrich Bodenhofer, Christoph Herwig
Chromatography is one of the most versatile unit operations in the biotechnological industry. Regulatory initiatives like Process Analytical Technology and Quality by Design led to the implementation of new chromatographic devices. Those represent an almost inexhaustible source of data. However, the analysis of large datasets is complicated, and significant amounts of information stay hidden in big data.Here we present a new, top-down approach for the systematic analysis of chromatographic datasets. It is the goal of this approach to analyze the dataset as a whole, starting with the most important, global information. The workflow should highlight interesting regions (outliers, drifts, data inconsistencies), and help to localize those regions within a multi-dimensional space in a straightforward way.Moving window factor models were used to extract the most important information, focusing on the differences between samples. The prototype was implemented as an interactive visualization tool for the explorative analysis of complex datasets. We found that the tool makes it convenient to localize variances in a multidimensional dataset and allows to differentiate between explainable and unexplainable variance. Starting with one global difference descriptor per sample, the analysis ends up with highly resolute temporally dependent difference descriptor values, thought as a starting point for the detailed analysis of the underlying raw data.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Valentin Steinwandter, Michal Šišmiš, Patrick Sagmeister, Ulrich Bodenhofer, Christoph Herwig

Chromatography is one of the most versatile unit operations in the biotechnological industry. Regulatory initiatives like Process Analytical Technology and Quality by Design led to the implementation of new chromatographic devices. Those represent an almost inexhaustible source of data. However, the analysis of large datasets is complicated, and significant amounts of information stay hidden in big data. Here we present a new, top-down approach for the systematic analysis of chromatographic datasets. It is the goal of this approach to analyze the dataset as a whole, starting with the most important, global information. The workflow should highlight interesting regions (outliers, drifts, data inconsistencies), and help to localize those regions within a multi-dimensional space in a straightforward way. Moving window factor models were used to extract the most important information, focusing on the differences between samples. The prototype was implemented as an interactive visualization tool for the explorative analysis of complex datasets. We found that the tool makes it convenient to localize variances in a multidimensional dataset and allows to differentiate between explainable and unexplainable variance. Starting with one global difference descriptor per sample, the analysis ends up with highly resolute temporally dependent difference descriptor values, thought as a starting point for the detailed analysis of the underlying raw data.





Chromatographic test methods for characterizing alkylsiloxane-bonded silica columns for reversed-phase liquid chromatography

Publication date: 15 August 2018 Source:Journal of Chromatography B, Volume 1092 Author(s): Colin F. Poole Major obstacles to formulating a simple retention mechanism for reversed-phase liquid chromatography have a direct impact on t…

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Colin F. Poole

Major obstacles to formulating a simple retention mechanism for reversed-phase liquid chromatography have a direct impact on the development of experimental methods for column characterization as they limit our capability to understand observed differences in retention at a system level. These problems arise from the heterogeneous composition of the stationary phase, the difficulty of providing a working definition for the phase ratio, and uncertainty as to whether the distribution mechanism for varied compounds is a partition, adsorption or mixed (combination) of these models. Retention factor and separation factor measurements offer little guidance as they represent an average of various and variable contributing factors that can only be interpreted by assuming a specific model. Column characterization methods have tended to ignore these difficulties by inventing a series of terms to describe column properties, such as hydrophobicity, hydrophilicity, silanol activity, steric resistance, etc., without proper definition. This has allowed multiple scales to be proposed for the same property which generally are only weakly correlated. Against this background we review the major approaches for the characterization of alkylsiloxane-bonded silica stationary phases employing prototypical compounds, the hydrophobic-subtraction model and the solvation parameter model. Those methods using prototypical compounds are limited by the lack of compounds with a singular dominant interaction. The multivariate approaches that extract column characteristic properties from the retention of varied compounds are more hopeful but it is important to be more precise in defining the characteristic column properties and cognizant that general interpretation of these properties for varied columns cannot escape the problem of a poor understanding of the distribution mechanism.





Simultaneous determination of six bioactive saponins from Rhizoma Panacis Japonici in rat plasma by UHPLC-MS/MS: Application to a pharmacokinetic study

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Hong Zheng, Feng Qiu, Hui Zhao, Jie Chen, Lei Wang, Haiyan Zou
A specific, sensitive and rapid ultra high performance liquid chromatography-tandem mass spectrometric (UHPLC-MS/MS) method was developed and validated for simultaneous determination of six major bioactive constituents in Rhizoma Panacis Japonici (RPJ), including oleanolic acid-type chikusetsusaponin V, IV, hemsgiganoside B, damarane-type ginsenoside Rb1, Rg1 and Re in rat plasma, using estazolam as the internal standard (IS). Plasma samples were pretreated with methanol/acetonitrile (1:1, V/V) for protein precipitation. Chromatographic separation was performed on an Agilent Eclipse Plus C18 column, using a gradient mobile phase consisting of methanol and 0.1% formic acid aqueous solution. A tandem mass spectrometric detection with an electrospray ionization (ESI) interface was conducted via multiple reaction monitoring (MRM) under positive ionization mode. For all the six analytes of interest, the calibration curves were linear in the concentration range of 2.00–500 ng/mL with r ≥ 0.9956. The intra- and inter-day precisions (in terms of relative standard deviation, RSD) were all below 10.2% and the accuracies (in terms of relative error, RE) were within −5.0% to 6.3% for all six analytes. Extraction recovery, matrix effect and stability data all met the acceptance criteria of FDA guideline for bioanalytical method validation. The developed method was applied to the pharmacokinetic study in rat. After oral administration of the total saponins from RPJ, six analytes were quickly absorbed into the blood and presented the phenomenon of double peaks. Among the six analytes, ginsenoside Rb1 showed slowest elimination from plasma with a t1/2z of 16.00 h, while that of the others were between 1.72 and 5.62 h. In conclusion, the developed method was successfully used to simultaneously analyze major oleanolic acid-type and damarane-type saponins of RPJ in rat plasma after oral administration.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Hong Zheng, Feng Qiu, Hui Zhao, Jie Chen, Lei Wang, Haiyan Zou

A specific, sensitive and rapid ultra high performance liquid chromatography-tandem mass spectrometric (UHPLC-MS/MS) method was developed and validated for simultaneous determination of six major bioactive constituents in Rhizoma Panacis Japonici (RPJ), including oleanolic acid-type chikusetsusaponin V, IV, hemsgiganoside B, damarane-type ginsenoside Rb1, Rg1 and Re in rat plasma, using estazolam as the internal standard (IS). Plasma samples were pretreated with methanol/acetonitrile (1:1, V/V) for protein precipitation. Chromatographic separation was performed on an Agilent Eclipse Plus C18 column, using a gradient mobile phase consisting of methanol and 0.1% formic acid aqueous solution. A tandem mass spectrometric detection with an electrospray ionization (ESI) interface was conducted via multiple reaction monitoring (MRM) under positive ionization mode. For all the six analytes of interest, the calibration curves were linear in the concentration range of 2.00–500 ng/mL with r ≥ 0.9956. The intra- and inter-day precisions (in terms of relative standard deviation, RSD) were all below 10.2% and the accuracies (in terms of relative error, RE) were within −5.0% to 6.3% for all six analytes. Extraction recovery, matrix effect and stability data all met the acceptance criteria of FDA guideline for bioanalytical method validation. The developed method was applied to the pharmacokinetic study in rat. After oral administration of the total saponins from RPJ, six analytes were quickly absorbed into the blood and presented the phenomenon of double peaks. Among the six analytes, ginsenoside Rb1 showed slowest elimination from plasma with a t 1/2z of 16.00 h, while that of the others were between 1.72 and 5.62 h. In conclusion, the developed method was successfully used to simultaneously analyze major oleanolic acid-type and damarane-type saponins of RPJ in rat plasma after oral administration.





First report on the pharmacokinetic profile of nimbolide, a novel anticancer agent in oral and intravenous administrated rats by LC/MS method

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Shandilya Mahamuni Baira, Amit Khurana, Jaganmohan Somagoni, R. Srinivas, Chandraiah Godugu, M.V.N. Kumar Talluri
Nimbolide is a novel, natural compound with promising potential as a drug candidate for anticancer activity. It is isolated from the Indian traditional medicinal plant Azadirachta indica popularly known as neem. The present study was undertaken to explore the oral bioavailability and pharmacokinetic characteristics of nimbolide in rats using the LC/QTOF/MS method. A simple protein precipitation method using acetonitrile was employed for extracting nimbolide from rat plasma. The chromatographic separation of nimbolide and the internal standard (regorafenib) was attained on an Aquity BEH C18 column (100 × 2.1 mm, 2.7 μm), using ACN and 0.1% of formic acid in water as mobile phase components in a gradient elution mode at a flow rate of 0.45 mL/min over a short run time of 4 min. A mass detection was carried out using target ions of [M + H]+ at m/z 467.2074 for nimbolide and m/z 483.0847 for the internal standard. The LC/MS method was validated and all the parameters were found well within the specified limits. The calibration curve was constructed in the range of 1–1000 ng/mL. The method shows good accuracy (91.66–97.12%) and precision (intra 2.21–6.92% CV and inter-day 2.56–4.62% CV). This developed LC/MS method was effectively applied to the pharmacokinetic study of nimbolide upon oral and intravenous administration in rats. In concordance with its physicochemical properties and high lipophilicity, we found that it shows poor oral absorption at different doses (10, 30 and 50 mg/kg). As expected, higher plasma levels were observed upon intravenous (10 mg/kg) administration. This method can be extended for evaluation of drug interaction and drug metabolism in rats as well as in humans. Moreover, our rapid and sensitive method may cater the need to accelerate the preclinical formulation development and lead optimization for future drug development of this potent anticancer agent. Further, our oral bioavailability studies demonstrated that nimbolide possesses poor oral absorption, which could be the probable reason for the delay in therapeutic translation of this promising agent for clinical use.

Graphical abstract

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Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Shandilya Mahamuni Baira, Amit Khurana, Jaganmohan Somagoni, R. Srinivas, Chandraiah Godugu, M.V.N. Kumar Talluri

Nimbolide is a novel, natural compound with promising potential as a drug candidate for anticancer activity. It is isolated from the Indian traditional medicinal plant Azadirachta indica popularly known as neem. The present study was undertaken to explore the oral bioavailability and pharmacokinetic characteristics of nimbolide in rats using the LC/QTOF/MS method. A simple protein precipitation method using acetonitrile was employed for extracting nimbolide from rat plasma. The chromatographic separation of nimbolide and the internal standard (regorafenib) was attained on an Aquity BEH C18 column (100 × 2.1 mm, 2.7 μm), using ACN and 0.1% of formic acid in water as mobile phase components in a gradient elution mode at a flow rate of 0.45 mL/min over a short run time of 4 min. A mass detection was carried out using target ions of [M + H]+ at m/z 467.2074 for nimbolide and m/z 483.0847 for the internal standard. The LC/MS method was validated and all the parameters were found well within the specified limits. The calibration curve was constructed in the range of 1–1000 ng/mL. The method shows good accuracy (91.66–97.12%) and precision (intra 2.21–6.92% CV and inter-day 2.56–4.62% CV). This developed LC/MS method was effectively applied to the pharmacokinetic study of nimbolide upon oral and intravenous administration in rats. In concordance with its physicochemical properties and high lipophilicity, we found that it shows poor oral absorption at different doses (10, 30 and 50 mg/kg). As expected, higher plasma levels were observed upon intravenous (10 mg/kg) administration. This method can be extended for evaluation of drug interaction and drug metabolism in rats as well as in humans. Moreover, our rapid and sensitive method may cater the need to accelerate the preclinical formulation development and lead optimization for future drug development of this potent anticancer agent. Further, our oral bioavailability studies demonstrated that nimbolide possesses poor oral absorption, which could be the probable reason for the delay in therapeutic translation of this promising agent for clinical use.

Graphical abstract

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Simultaneous measurement of folate cycle intermediates in different biological matrices using liquid chromatography–tandem mass spectrometry

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Jatin Nandania, Meri Kokkonen, Liliya Euro, Vidya Velagapudi
The folate cycle is an essential metabolic pathway in the cell, involved in nucleotide synthesis, maintenance of the redox balance in the cell, methionine metabolism and re-methylation reactions. Standardised methods for the measurement of folate cycle intermediates in different biological matrices are in great demand. Here we describe a rapid, sensitive, precise and accurate liquid chromatographic–tandem mass spectrometric (LC–MS/MS) method with a wide calibration curve range and a short run time for the simultaneous determination of folate cycle metabolites, including tetrahydrofolic acid (THF), 5‑methyl THF, 5‑formyl THF, 5,10‑methenyl THF, 5,10‑methylene THF, dihydrofolic acid (DHF) and folic acid in different biological matrices. Extraction of folate derivatives from soft and hard tissue samples as well as from adherent cells was achieved using homogenisation in buffer, while extraction from the whole blood and plasma relied on the anion exchange solid-phase extraction (SPE) method. Chromatographic separation was completed using a Waters Atlantis dC18 2.0 × 100 mm, 3-μ column with a gradient elution using formic acid in water (0.1% v/v) and acetonitrile as the mobile phases. LC gradient started with 95% of the aqueous phase which was gradually changed to 95% of the organic phase during 2.70 min in order to separate the selected metabolites. The analytes were separated with a run time of 5 min at a flow rate of 0.300 mL/min and detected using a Waters Xevo-TQS triple quadrupole mass spectrometer in the multiple reaction monitoring mode (MRM) at positive polarity. The instrument response was linear over a calibration range of 0.5 to 2500 ng/mL (r2 > 0.980). The developed bioanalytical method was thoroughly validated in terms of accuracy, precision, linearity, recovery, sensitivity and stability for tissue and blood samples. The matrix effect was compensated by using structurally similar isotope labelled internal standard (IS), 13C5‑methyl THF, for all folate metabolites. However, not all folate metabolites can be accurately quantified using this method due to their high interconversion rates especially at low pH. This applies to 5,10‑methylene THF which interconverts into THF, and 5,10‑methenyl‑THF interconverting into 5‑formyl‑THF. Using this method, we measured folate cycle intermediates in mouse bone marrow cells and plasma, in human whole blood; in mouse muscle, liver, heart and brain samples.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Jatin Nandania, Meri Kokkonen, Liliya Euro, Vidya Velagapudi

The folate cycle is an essential metabolic pathway in the cell, involved in nucleotide synthesis, maintenance of the redox balance in the cell, methionine metabolism and re-methylation reactions. Standardised methods for the measurement of folate cycle intermediates in different biological matrices are in great demand. Here we describe a rapid, sensitive, precise and accurate liquid chromatographic–tandem mass spectrometric (LC–MS/MS) method with a wide calibration curve range and a short run time for the simultaneous determination of folate cycle metabolites, including tetrahydrofolic acid (THF), 5‑methyl THF, 5‑formyl THF, 5,10‑methenyl THF, 5,10‑methylene THF, dihydrofolic acid (DHF) and folic acid in different biological matrices. Extraction of folate derivatives from soft and hard tissue samples as well as from adherent cells was achieved using homogenisation in buffer, while extraction from the whole blood and plasma relied on the anion exchange solid-phase extraction (SPE) method. Chromatographic separation was completed using a Waters Atlantis dC18 2.0 × 100 mm, 3-μ column with a gradient elution using formic acid in water (0.1% v/v) and acetonitrile as the mobile phases. LC gradient started with 95% of the aqueous phase which was gradually changed to 95% of the organic phase during 2.70 min in order to separate the selected metabolites. The analytes were separated with a run time of 5 min at a flow rate of 0.300 mL/min and detected using a Waters Xevo-TQS triple quadrupole mass spectrometer in the multiple reaction monitoring mode (MRM) at positive polarity. The instrument response was linear over a calibration range of 0.5 to 2500 ng/mL (r2 > 0.980). The developed bioanalytical method was thoroughly validated in terms of accuracy, precision, linearity, recovery, sensitivity and stability for tissue and blood samples. The matrix effect was compensated by using structurally similar isotope labelled internal standard (IS), 13C5‑methyl THF, for all folate metabolites. However, not all folate metabolites can be accurately quantified using this method due to their high interconversion rates especially at low pH. This applies to 5,10‑methylene THF which interconverts into THF, and 5,10‑methenyl‑THF interconverting into 5‑formyl‑THF. Using this method, we measured folate cycle intermediates in mouse bone marrow cells and plasma, in human whole blood; in mouse muscle, liver, heart and brain samples.





Ochratoxin A determination in swine muscle and liver from French conventional or organic farming production systems

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Vincent Hort, Marina Nicolas, Brice Minvielle, Corentin Maleix, Caroline Desbourdes, Frédéric Hommet, Sylviane Dragacci, Gaud Dervilly-Pinel, Erwan Engel, Thierry Guérin
Consumers generally considered organic products to be healthier and safer but data regarding the contamination of organic products are scarce. This study evaluated the impact of the farming system on the levels of ochratoxin A (OTA) in the tissues of French pigs (muscle and liver) reared following three different types of production (organic, Label Rouge and conventional). Because OTA is present at trace levels in animal products, a sensitive ultra-high performance liquid chromatography–tandem mass spectrometry method using stable isotope dilution assay was developed and validated. OTA was detected or quantified (LOQ of 0.10 μg kg−1) in 67% (n = 47) of the 70 pig liver samples analysed, with concentrations ranging from <0.10 to 3.65 μg kg−1. The maximum concentration was found in a sample from organic production but there were no significant differences in the content of OTA between farming systems. OTA was above the LOQ in four out of 25 samples of the pork muscles. A good agreement was found between OTA levels in muscle and liver (liver concentration = 2.9 × OTA muscle concentration, r = 0.981).

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Vincent Hort, Marina Nicolas, Brice Minvielle, Corentin Maleix, Caroline Desbourdes, Frédéric Hommet, Sylviane Dragacci, Gaud Dervilly-Pinel, Erwan Engel, Thierry Guérin

Consumers generally considered organic products to be healthier and safer but data regarding the contamination of organic products are scarce. This study evaluated the impact of the farming system on the levels of ochratoxin A (OTA) in the tissues of French pigs (muscle and liver) reared following three different types of production (organic, Label Rouge and conventional). Because OTA is present at trace levels in animal products, a sensitive ultra-high performance liquid chromatography–tandem mass spectrometry method using stable isotope dilution assay was developed and validated. OTA was detected or quantified (LOQ of 0.10 μg kg−1) in 67% (n = 47) of the 70 pig liver samples analysed, with concentrations ranging from <0.10 to 3.65 μg kg−1. The maximum concentration was found in a sample from organic production but there were no significant differences in the content of OTA between farming systems. OTA was above the LOQ in four out of 25 samples of the pork muscles. A good agreement was found between OTA levels in muscle and liver (liver concentration = 2.9 × OTA muscle concentration, r = 0.981).





Gas chromatography-mass spectrometry based plasma metabolomics of H1N1-induced inflammation in mice and intervention with Flos Lonicerae Japonica-Fructus Forsythiae herb pair

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Wenjuan Qian, An Kang, Linxiu Peng, Tong Xie, Jianjian Ji, Wei Zhou, Jinjun Shan, Liuqing Di
Flos Lonicerae Japonica-Fructus Forsythiae herb pair (Yin-Qiao in Chinese, YQ), is used clinically for the treatment of viral pneumonia due to its heat-clearing and detoxifying functions. In the present work, the effect of YQ in H1N1-induced inflammation in mice was investigated by metabolomics based on GC–MS. Body weight and histological results were used to assess the lung injury, while the levels of IL-6 and TNF-α in plasma were used to evaluate the extent of inflammation. The acquired GC–MS data were further subjected to multivariate data analysis, and the significantly altered metabolites identified. After statistical and pathway analysis, 17 significantly altered metabolites and 3 possible metabolic pathways were found in plasma between normal and H1N1-induced pneumonia mice, while 17 significant differential metabolites were identified when YQ treatment group was compared with model group. This work indicates that oral administration of YQ could protect mice from H1N1-induced inflammation partially by ameliorating the associated metabolic disturbances.

Graphical abstract

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Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Wenjuan Qian, An Kang, Linxiu Peng, Tong Xie, Jianjian Ji, Wei Zhou, Jinjun Shan, Liuqing Di

Flos Lonicerae Japonica-Fructus Forsythiae herb pair (Yin-Qiao in Chinese, YQ), is used clinically for the treatment of viral pneumonia due to its heat-clearing and detoxifying functions. In the present work, the effect of YQ in H1N1-induced inflammation in mice was investigated by metabolomics based on GC–MS. Body weight and histological results were used to assess the lung injury, while the levels of IL-6 and TNF-α in plasma were used to evaluate the extent of inflammation. The acquired GC–MS data were further subjected to multivariate data analysis, and the significantly altered metabolites identified. After statistical and pathway analysis, 17 significantly altered metabolites and 3 possible metabolic pathways were found in plasma between normal and H1N1-induced pneumonia mice, while 17 significant differential metabolites were identified when YQ treatment group was compared with model group. This work indicates that oral administration of YQ could protect mice from H1N1-induced inflammation partially by ameliorating the associated metabolic disturbances.

Graphical abstract

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Simultaneous quantification of 18 saturated and unsaturated fatty acids and 7 sterols as their tert-butyldimethylsilyl derivatives in human saliva using gas chromatography-tandem mass spectrometry

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Ju-Yeon Moon, Tae Yeon Kong, Hyun-Jun Jang, Han Chang Kang, Yong-Yeon Cho, Joo Young Lee, Hye Suk Lee
The profiling of fatty acids (FAs) or sterols has been applied in clinical studies, but still needs to be improved to enable their simultaneous quantification. Moreover, little progress has been made in determining the levels of FAs and sterols in human saliva in a single run. In this study, gas chromatography-tandem mass spectrometry (GC–MS/MS) using one-step tert-butyldimethylsilyl (TBDMS) derivatization was developed for comprehensive profiling of 18 FAs (eight saturated, five monounsaturated, and five polyunsaturated FAs) and 7 sterols (cholesterol and its precursors). The TBDMS derivatization process was also optimized in terms of reaction solvent, catalyst, temperature, and reaction time. The optimized conditions resulted in better derivatization efficiency with good chromatographic separation through a high-temperature column within 23 min. The present method provided good linearity (r > 0.993), precision (coefficient of variation, 2.7% to 10.4%), and accuracy (91.5% to 103.4%). The overall recovery ranged from 73.8% to 114.3% for the 18 FAs, and from 68.9% to 79.8% for the 7 sterols. The validated method was applied to characterize FAs and sterols in human saliva samples. This is the first report of a GC–MS/MS method for the simultaneous determination of various FAs and sterols from a small volume (100 μL) of saliva. This approach can be used as a primary screening tool to examine the levels of both FAs and sterols in saliva, providing detailed information about their homeostasis for diagnostic and prognostic purposes.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Ju-Yeon Moon, Tae Yeon Kong, Hyun-Jun Jang, Han Chang Kang, Yong-Yeon Cho, Joo Young Lee, Hye Suk Lee

The profiling of fatty acids (FAs) or sterols has been applied in clinical studies, but still needs to be improved to enable their simultaneous quantification. Moreover, little progress has been made in determining the levels of FAs and sterols in human saliva in a single run. In this study, gas chromatography-tandem mass spectrometry (GC–MS/MS) using one-step tert-butyldimethylsilyl (TBDMS) derivatization was developed for comprehensive profiling of 18 FAs (eight saturated, five monounsaturated, and five polyunsaturated FAs) and 7 sterols (cholesterol and its precursors). The TBDMS derivatization process was also optimized in terms of reaction solvent, catalyst, temperature, and reaction time. The optimized conditions resulted in better derivatization efficiency with good chromatographic separation through a high-temperature column within 23 min. The present method provided good linearity (r > 0.993), precision (coefficient of variation, 2.7% to 10.4%), and accuracy (91.5% to 103.4%). The overall recovery ranged from 73.8% to 114.3% for the 18 FAs, and from 68.9% to 79.8% for the 7 sterols. The validated method was applied to characterize FAs and sterols in human saliva samples. This is the first report of a GC–MS/MS method for the simultaneous determination of various FAs and sterols from a small volume (100 μL) of saliva. This approach can be used as a primary screening tool to examine the levels of both FAs and sterols in saliva, providing detailed information about their homeostasis for diagnostic and prognostic purposes.





A method for determination of aldosterone in adrenal tributary venous serum by derivatization using Girard P reagent isotopologues followed by LC/ESI-MS/MS

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Tatsuya Higashi, Miho Akaishi, Mai Yokota, Tatsunori Suzuki, Shoujiro Ogawa, Yuki Sugiura, Tetsuo Nishikawa, Koshiro Nishimoto, Makoto Suematsu
The quantification of aldosterone (ALD) in adrenal tributary venous blood serum/plasma combined with the super-selective adrenal venous sampling (ssAVS) technique is recognized as a definitive procedure for differentiation of the forms of primary aldosteronism (PA), identification of the affected segment(s) and operating decision-making. In this study, an enhanced throughput and sensitive method was developed and validated for the quantification of ALD in ssAVS serum samples by liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) combined with derivatization using the Girard P reagent (GP) isotopologues (2H0- and 2H5-GP). The right and left adrenal serum samples were separately pretreated and derivatized with either isotopologue. The two samples were then combined and injected together for LC/ESI-MS/MS analysis. Based on the mass differences between the isotopologues, the derivatized ALD in the two samples were quantified within a single run. This method enabled the reproducible (intra- and inter-assay relative standard deviations, 6.6% or lower) and accurate (98.2–107.0%) quantification of the serum ALD using a 25-μL sample, and the lower limit of quantification was 1.0 ng/mL. The developed method was used for the analysis of 11 pairs of ssAVS serum samples (total of 22 samples) of patients with ALD-producing adenoma and proven to have a satisfactory applicability; this method enabled the identification of the affected adrenal and the determination of the laterality of PA, and reduced the analysis time to about 2/3 compared to the previous method for 22 samples.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Tatsuya Higashi, Miho Akaishi, Mai Yokota, Tatsunori Suzuki, Shoujiro Ogawa, Yuki Sugiura, Tetsuo Nishikawa, Koshiro Nishimoto, Makoto Suematsu

The quantification of aldosterone (ALD) in adrenal tributary venous blood serum/plasma combined with the super-selective adrenal venous sampling (ssAVS) technique is recognized as a definitive procedure for differentiation of the forms of primary aldosteronism (PA), identification of the affected segment(s) and operating decision-making. In this study, an enhanced throughput and sensitive method was developed and validated for the quantification of ALD in ssAVS serum samples by liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) combined with derivatization using the Girard P reagent (GP) isotopologues (2H0- and 2H5-GP). The right and left adrenal serum samples were separately pretreated and derivatized with either isotopologue. The two samples were then combined and injected together for LC/ESI-MS/MS analysis. Based on the mass differences between the isotopologues, the derivatized ALD in the two samples were quantified within a single run. This method enabled the reproducible (intra- and inter-assay relative standard deviations, 6.6% or lower) and accurate (98.2–107.0%) quantification of the serum ALD using a 25-μL sample, and the lower limit of quantification was 1.0 ng/mL. The developed method was used for the analysis of 11 pairs of ssAVS serum samples (total of 22 samples) of patients with ALD-producing adenoma and proven to have a satisfactory applicability; this method enabled the identification of the affected adrenal and the determination of the laterality of PA, and reduced the analysis time to about 2/3 compared to the previous method for 22 samples.





Pharmacokinetic, bioavailability and tissue distribution study of MP3950, a new gastroprokinetic candidate compound, in rat using UPLC-MS/MS

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Yu Zhao, Min Zhao, Qi Jiang, Feng Qin, Chengying Wang, Zhili Xiong, Shaojie Wang, Zhonggui He, Xingjie Guo, Longshan Zhao
MP3950 is being developed as a gastroprokinetic candidate compound. To illustrate the pharmacokinetic profiles, absolute bioavailability after intravenous administration and oral administration with MP3950 as well as tissue distribution in vivo, an UPLC-MS/MS approach which was rapid and selective was developed to determine MP3950 in plasma and tissue of rat. Sample pre-treatment of plasma sample was one-step protein precipitation. 0.1% formic acid containing 5 mmol/L ammonium acetate-methanol(55/45,v/v) was used for isocratic elution on a Waters ACQUITY UPLC® BEH C18 (50 mm × 2.1 mm, 1.7 μm) to achieve the separation. The analysis was performed in MRM mode via positive ESI mode. LLOQ of the method was 10 ng/mL, and the linearity up to 10,000 ng/mL. The intra-day precision (relative standard deviation, RSD) was 4.0–9.0% and the inter-day precision was 4.2–10.6%. The accuracy (relative error, RE) was −1.2–2.4%. Tissue samples were collected from the brain, heart, liver, spleen, lung, kidney, stomach, duodenum, small intestine, large intestine, appendix and skeletal muscle. The same liquid chromatographic and mass spectrometric conditions were used, and it’s proven that this method was feasible to analyze the MP3950 in tissues with good precision and accuracy over the range from 10 to 5000 ng·mL−1. It was found that the concentration of MP3950 is higher in digestive system. The tissue distribution, pharmacokinetic and bioavailability of MP3950 in rats were carried out by the method for the first time, which can provide enough information for the further development and investigation of MP3950.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Yu Zhao, Min Zhao, Qi Jiang, Feng Qin, Chengying Wang, Zhili Xiong, Shaojie Wang, Zhonggui He, Xingjie Guo, Longshan Zhao

MP3950 is being developed as a gastroprokinetic candidate compound. To illustrate the pharmacokinetic profiles, absolute bioavailability after intravenous administration and oral administration with MP3950 as well as tissue distribution in vivo, an UPLC-MS/MS approach which was rapid and selective was developed to determine MP3950 in plasma and tissue of rat. Sample pre-treatment of plasma sample was one-step protein precipitation. 0.1% formic acid containing 5 mmol/L ammonium acetate-methanol(55/45,v/v) was used for isocratic elution on a Waters ACQUITY UPLC® BEH C18 (50 mm × 2.1 mm, 1.7 μm) to achieve the separation. The analysis was performed in MRM mode via positive ESI mode. LLOQ of the method was 10 ng/mL, and the linearity up to 10,000 ng/mL. The intra-day precision (relative standard deviation, RSD) was 4.0–9.0% and the inter-day precision was 4.2–10.6%. The accuracy (relative error, RE) was −1.2–2.4%. Tissue samples were collected from the brain, heart, liver, spleen, lung, kidney, stomach, duodenum, small intestine, large intestine, appendix and skeletal muscle. The same liquid chromatographic and mass spectrometric conditions were used, and it's proven that this method was feasible to analyze the MP3950 in tissues with good precision and accuracy over the range from 10 to 5000 ng·mL−1. It was found that the concentration of MP3950 is higher in digestive system. The tissue distribution, pharmacokinetic and bioavailability of MP3950 in rats were carried out by the method for the first time, which can provide enough information for the further development and investigation of MP3950.





Development of an automated high-throughput sample preparation protocol for LC-MS/MS analysis of glycated peptides

Publication date: 15 August 2018 Source:Journal of Chromatography B, Volume 1092 Author(s): Jongho Jeon, Jiwon Yang, Jong-Moon Park, Na-Young Han, Yeong-Bae Lee, Hookeun Lee Advanced glycation end products (AGEs) are known …

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Jongho Jeon, Jiwon Yang, Jong-Moon Park, Na-Young Han, Yeong-Bae Lee, Hookeun Lee

Advanced glycation end products (AGEs) are known to play a leading part in the pathogenesis of human diseases, such as diabetes, Alzheimer's disease, lateral sclerosis, and atherosclerosis. It is for this reason that research on AGEs is crucial and large-scale studies are needed for the treatment of diseases. The aim of this study was to develop a reproducible method to analyze Amadori compounds using an automated enrichment protocol for high-throughput analysis of clinical samples. The developed method enabled the enrichment of Amadori compounds simultaneously from 96 samples, and it was applied to the discovery of biomarkers in AGEs related diseases. In this study, ten human serum samples were processed using automated filter-aided sample preparation (aFASP) in a 96-well filter plate, and the eluted peptide mixtures were enriched by Affinity Cellufine PB in a fritted 96-well filter plate using a liquid handling robotic system. The eluted glycated peptides were analyzed by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system. A total of 982 unique glycated peptides, corresponding to 524 unique glycated proteins, were identified from the analysis of ten human samples. The advantages and potentials of the automated sample preparation system were demonstrated through label free quantification of the glycated peptides.





Microwave assisted extraction for the determination of chlorogenic acid in Flos Lonicerae by direct analysis in real time mass spectrometry (DART-MS)

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Xiao-Hui Yao, Jian-Yi Xu, Jing-Yi Hao, Yi Wan, Tao Chen, Dong-Yang Zhang, Long Li
Flos Lonicerae was an important Chinese medicine. In this research, a microwave assisted extraction method was applied for the extraction of chlorogenic acid from Flos Lonicerae. The operating conditions were optimized using a Box–Behnken design test. Under the optimal conditions, the extraction yield of chlorogenic acid reached 32.52 ± 1.31 mg/g. Next, a direct analysis in real time mass spectrometry (DART-MS) method was utilized to quantify of chlorogenic acid in Flos Lonicerae extracts. The primary parameters were optimized to obtain maximum signal intensity. In the detection process of the actual samples, the results obtained by DART–MS are consistent with those obtained by HPLC method with short detection time and acceptable repeatability and precision (<15%). In addition, the DART–MS/MS method has several advantages, such as speed, low cost and simplicity. Therefore, the DART-MS method is an efficient method that can be applied in the quantification of chlorogenic acid in Flos Lonicerae.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Xiao-Hui Yao, Jian-Yi Xu, Jing-Yi Hao, Yi Wan, Tao Chen, Dong-Yang Zhang, Long Li

Flos Lonicerae was an important Chinese medicine. In this research, a microwave assisted extraction method was applied for the extraction of chlorogenic acid from Flos Lonicerae. The operating conditions were optimized using a Box–Behnken design test. Under the optimal conditions, the extraction yield of chlorogenic acid reached 32.52 ± 1.31 mg/g. Next, a direct analysis in real time mass spectrometry (DART-MS) method was utilized to quantify of chlorogenic acid in Flos Lonicerae extracts. The primary parameters were optimized to obtain maximum signal intensity. In the detection process of the actual samples, the results obtained by DART–MS are consistent with those obtained by HPLC method with short detection time and acceptable repeatability and precision (<15%). In addition, the DART–MS/MS method has several advantages, such as speed, low cost and simplicity. Therefore, the DART-MS method is an efficient method that can be applied in the quantification of chlorogenic acid in Flos Lonicerae.





Microdialysis combined with RRLC–MS/MS for the pharmacokinetics of two major alkaloids of Bi qi capsule and the potential roles of P-gp and BCRP on their penetration

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Tiankun Ren, Menglin Li, Hao Zheng, Wenwei Liu, Jinlan Zhang
Bi qi capsule (BQC) is a traditional Chinese medicine prescription that is clinically used for the treatment of rheumatoid arthritis. Strychnine and brucine, as two typical kinds of alkaloids, are the primary active and neurotoxic constituents of BQC. In this study, a sensitive and reliable rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS/MS) quantitative method was used to determine the concentrations of brucine and strychnine in rat brain and blood dialysates. The blood-brain barrier (BBB) penetration of free brucine and strychnine and their pharmacokinetic characteristics were investigated by the validated RRLC-MS/MS method coupled with in vivo microdialysis for the first time. The dialysate brain-blood AUC ratios of brucine were 0.098, 0.44 and 0.40 respectively at 0.4, 0.8 and 1.6 g kg−1 doses of BQC, and the dialysate brain-blood AUC ratios of strychnine were 0.20, 1.25 and 2.06 respectively at 0.4, 0.8 and 1.6 g kg−1 doses of BQC. The high brain-blood AUC ratios of brucine and strychnine were observed in medium and high dose groups of BQC. In addition, the effects of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) on brucine and strychnine across BBB were also studied using the above method as well as molecular docking. The results prompted that brucine was the substrate of P-gp, and strychnine might be the inhibitor of P-gp. Brucine and strychnine showed high brain penetration, so it is very important to well control the clinic dosage of BQC and manufactory quality for avoiding the side effects and obtaining good therapeutic efficacy. Our study could be further used in investigating BBB penetration for other drugs caused neurotoxicity.

Graphical abstract

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Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Tiankun Ren, Menglin Li, Hao Zheng, Wenwei Liu, Jinlan Zhang

Bi qi capsule (BQC) is a traditional Chinese medicine prescription that is clinically used for the treatment of rheumatoid arthritis. Strychnine and brucine, as two typical kinds of alkaloids, are the primary active and neurotoxic constituents of BQC. In this study, a sensitive and reliable rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS/MS) quantitative method was used to determine the concentrations of brucine and strychnine in rat brain and blood dialysates. The blood-brain barrier (BBB) penetration of free brucine and strychnine and their pharmacokinetic characteristics were investigated by the validated RRLC-MS/MS method coupled with in vivo microdialysis for the first time. The dialysate brain-blood AUC ratios of brucine were 0.098, 0.44 and 0.40 respectively at 0.4, 0.8 and 1.6 g kg−1 doses of BQC, and the dialysate brain-blood AUC ratios of strychnine were 0.20, 1.25 and 2.06 respectively at 0.4, 0.8 and 1.6 g kg−1 doses of BQC. The high brain-blood AUC ratios of brucine and strychnine were observed in medium and high dose groups of BQC. In addition, the effects of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) on brucine and strychnine across BBB were also studied using the above method as well as molecular docking. The results prompted that brucine was the substrate of P-gp, and strychnine might be the inhibitor of P-gp. Brucine and strychnine showed high brain penetration, so it is very important to well control the clinic dosage of BQC and manufactory quality for avoiding the side effects and obtaining good therapeutic efficacy. Our study could be further used in investigating BBB penetration for other drugs caused neurotoxicity.

Graphical abstract

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Application of dispersive solid phase extraction for trace analysis of toxic chemicals in foods

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Sarah Neely, Jordan Martin, Natalia Ferreira da Cruz, Gavin Piester, Morgan Robinson, Richard Okoniewski, Buu N. Tran
The objectives of this study were to develop and validate a method for the identification of toxic organic chemicals, including groups of controlled substances, alkaloids and pesticides that are highly toxic and considered threats to public health. This project aims to ensure our laboratory’s readiness to respond to emergencies involving our food supply in cooperation with the Food Emergency Response Network (FERN) program. The food matrices were homogenized in a blender or food processor prior to extraction with an acetonitrile-water mixture using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure. The extracts were then analyzed by either gas chromatography–mass spectrometry (GC–MS) or liquid chromatography-electrospray tandem mass spectrometry (LC-ESI/MS/MS). Method validation was performed on a variety of food matrices including lettuce, grapes, milk, chicken, pork and beef. MDLs for the toxic compounds ranged from 0.01 to 0.66 mg/kg (ppm). The findings in this study will provide a valuable resource for the determination of toxic chemicals in food matrices for emergency response situations.

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Sarah Neely, Jordan Martin, Natalia Ferreira da Cruz, Gavin Piester, Morgan Robinson, Richard Okoniewski, Buu N. Tran

The objectives of this study were to develop and validate a method for the identification of toxic organic chemicals, including groups of controlled substances, alkaloids and pesticides that are highly toxic and considered threats to public health. This project aims to ensure our laboratory's readiness to respond to emergencies involving our food supply in cooperation with the Food Emergency Response Network (FERN) program. The food matrices were homogenized in a blender or food processor prior to extraction with an acetonitrile-water mixture using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure. The extracts were then analyzed by either gas chromatography–mass spectrometry (GC–MS) or liquid chromatography-electrospray tandem mass spectrometry (LC-ESI/MS/MS). Method validation was performed on a variety of food matrices including lettuce, grapes, milk, chicken, pork and beef. MDLs for the toxic compounds ranged from 0.01 to 0.66 mg/kg (ppm). The findings in this study will provide a valuable resource for the determination of toxic chemicals in food matrices for emergency response situations.





An insight into the determination of trace levels of benzodiazepines in biometric systems: Use of crab shell powder as an environmentally friendly biosorbent

Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092
Author(s): Fatemeh Samadi, Ali Sarafraz-Yazdi, Zarrin Es’haghi
A vortex assisted dispersive solid phase extraction approach (VADSPE) based on crab shell powder as biodegradable and biocompatible μ-sorbent was developed for simultaneous analysis of three benzodiazepines (BZPs): Oxazepam, Flurazepamand Diazepam, in biological matrixes included blood, nail, hair and urine samples. The effective parameters in VADSPE process, including the volume of uptake solvent, the dosage of sorbent, extraction time and back extraction time, were optimized using response surface methodology(RSM) based on central composite design(CCD). The suggested technique allows successful trapping of BZPs in a single-step extraction. Under the optimized extraction conditions, the proposed approach was exhibited low limits of detection (0.003–1.2 μg·mL−1), an acceptable linearity (0.04–20 μg·mL−1). Method performance was assessed by recovery experiments at spiking levels of 10 μg·mL−1(n = 5) for BZPs in blood, nail, hair and urine samples. Relative recoveries were determined by HPLC, which were between 36%and 95.6%.

Graphical abstract

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Publication date: 15 August 2018
Source:Journal of Chromatography B, Volume 1092

Author(s): Fatemeh Samadi, Ali Sarafraz-Yazdi, Zarrin Es'haghi

A vortex assisted dispersive solid phase extraction approach (VADSPE) based on crab shell powder as biodegradable and biocompatible μ-sorbent was developed for simultaneous analysis of three benzodiazepines (BZPs): Oxazepam, Flurazepamand Diazepam, in biological matrixes included blood, nail, hair and urine samples. The effective parameters in VADSPE process, including the volume of uptake solvent, the dosage of sorbent, extraction time and back extraction time, were optimized using response surface methodology(RSM) based on central composite design(CCD). The suggested technique allows successful trapping of BZPs in a single-step extraction. Under the optimized extraction conditions, the proposed approach was exhibited low limits of detection (0.003–1.2 μg·mL−1), an acceptable linearity (0.04–20 μg·mL−1). Method performance was assessed by recovery experiments at spiking levels of 10 μg·mL−1(n = 5) for BZPs in blood, nail, hair and urine samples. Relative recoveries were determined by HPLC, which were between 36%and 95.6%.

Graphical abstract

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