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Special Issue "Biological Sample Analysis by Liquid Chromatography"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Analytical Chemistry".

Deadline for manuscript submissions: closed (30 April 2019).

Special Issue Editor

Assoc. Prof. Dr. Makoto Tsunoda
Website
Guest Editor
Laboratory of Bio-Analytical Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo ku, Tokyo 113-0033, Japan
Interests: HPLC; fluorescence; chemiluminescence; microfluidics
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

The analysis of biological compounds in biological samples such as blood plasma, urine, and tissue is essential to clarify biological phenomena. The analysis of drug and its metabolites after in-vivo administration is also important. Separation is considered one of the most important analytical methods. Chromatographic methods, especially HPLC, appear to be the most common, because the techniques allow for the separation of a quite complicated mixtures of analytes.

In this Special Issue, the contribution of original research and review articles regarding separation techniques using liquid chromatography, which is applied to biological fluids, are welcome.

Dr. Makoto Tsunoda
Guest Editor

Manuscript Submission Information

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Keywords

  • HPLC 
  • sample preparation 
  • metabolome 
  • proteome 
  • blood
  • plasma
  • urine 
  • bioanalysis 
  • mass spectrometry

Published Papers (17 papers)

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Research

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Open AccessArticle
Comprehensive Characterization of Lignans from Forsythia viridissima by UHPLC-ESI-QTOF-MS, and Their NO Inhibitory Effects on RAW 264.7 Cells
Molecules 2019, 24(14), 2649; https://doi.org/10.3390/molecules24142649 - 22 Jul 2019
Abstract
Lignans are known to be an important class of phenylpropanoid secondary metabolites. In the course of our studies on the chemodiversity of lignans, the necessity arose to develop a method for the fast detection and identification of bioactive lignan subclasses. In this study, [...] Read more.
Lignans are known to be an important class of phenylpropanoid secondary metabolites. In the course of our studies on the chemodiversity of lignans, the necessity arose to develop a method for the fast detection and identification of bioactive lignan subclasses. In this study, we detected 10 lignan derivatives of different extracts of F. viridissima by UHPLC-ESI-QTOF-MS. Lignan glycosides (1 and 2), lignans (3 and 4), and lignan dimers (510) were identified by analysis of their exact masses and MSe spectra along with the characteristic mass fragmentation patterns and molecular formulas. We further investigated NO inhibitory effects of F. viridissima fractions and their major lignan derivatives to evaluate those anti-inflammatory effects. The methylene chloride fraction of F. viridissima as well as compounds 8 and 10 showed potent dose-dependent NO inhibitory effects on RAW 264.7 cells. Corresponding to the NO inhibition by compounds 8 and 10, lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) expression was notably reduced by both compounds. Our combined data with the bioactive results and the component analysis by UHPLC-ESI-QTOF-MS suggest that the methylene chloride fraction of F. viridissima roots could be potential anti-inflammatory agents and these are related to major lignans including dimeric dibenzylbutyrolactone lignans. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
An LC-MS/MS Method to Measure S-Methyl-l-Cysteine and S-Methyl-l-Cysteine Sulfoxide in Human Specimens Using Isotope Labelled Internal Standards
Molecules 2019, 24(13), 2427; https://doi.org/10.3390/molecules24132427 - 02 Jul 2019
Cited by 3
Abstract
This is the first report describing an analytical method for quantitative analysis of two naturally occurring sulphur compounds, S-methyl-l-cysteine (SMC) and S-methyl-l-cysteine sulfoxide (SMCSO), in human body fluids using isotope-labelled internal standards and liquid chromatography-mass spectrometry (LC-MS)/MS [...] Read more.
This is the first report describing an analytical method for quantitative analysis of two naturally occurring sulphur compounds, S-methyl-l-cysteine (SMC) and S-methyl-l-cysteine sulfoxide (SMCSO), in human body fluids using isotope-labelled internal standards and liquid chromatography-mass spectrometry (LC-MS)/MS techniques. This method was validated according to the guideline of the Royal Society of Chemistry Analytical Methods Committee. It offers significant advantages including simple and fast preparation of human biological samples. The limits of detection of SMC were 0.08 µM for urine and 0.04 µM for plasma. The limits of detection of SMCSO were 0.03 µM for urine and 0.02 µM for plasma. The calibration curves of all matrices showed linearity with correlation coefficients r2 > 0.9987. The intra and inter day precisions in three levels of known concentrations were >10% and >20%, respectively. The quantification accuracy was 98.28 ± 5.66%. The proposed method would be beneficial for the rapid and accurate determination of the SMC and SMCSO in human plasma and urine samples using by isotope labelled internal standards. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Quantitative Analysis of Tozadenant Using Liquid Chromatography-Mass Spectrometric Method in Rat Plasma and Its Human Pharmacokinetics Prediction Using Physiologically Based Pharmacokinetic Modeling
Molecules 2019, 24(7), 1295; https://doi.org/10.3390/molecules24071295 - 02 Apr 2019
Cited by 3
Abstract
Tozadenant is one of the selective adenosine A2a receptor antagonists with a potential to be a new Parkinson’s disease (PD) therapeutic drug. In this study, a liquid chromatography-mass spectrometry based bioanalytical method was qualified and applied for the quantitative analysis of tozadenant in [...] Read more.
Tozadenant is one of the selective adenosine A2a receptor antagonists with a potential to be a new Parkinson’s disease (PD) therapeutic drug. In this study, a liquid chromatography-mass spectrometry based bioanalytical method was qualified and applied for the quantitative analysis of tozadenant in rat plasma. A good calibration curve was observed in the range from 1.01 to 2200 ng/mL for tozadenant using a quadratic regression. In vitro and preclinical in vivo pharmacokinetic (PK) properties of tozadenant were studied through the developed bioanalytical methods, and human PK profiles were predicted using physiologically based pharmacokinetic (PBPK) modeling based on these values. The PBPK model was initially optimized using in vitro and in vivo PK data obtained by intravenous administration at a dose of 1 mg/kg in rats. Other in vivo PK data in rats were used to validate the PBPK model. The human PK of tozadenant after oral administration at a dose of 240 mg was simulated by using an optimized and validated PBPK model. The predicted human PK parameters and profiles were similar to the observed clinical data. As a result, optimized PBPK model could reasonably predict the PK in human. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Quantitative Characterization of Olaparib in Nanodelivery System and Target Cell Compartments by LC-MS/MS
Molecules 2019, 24(5), 989; https://doi.org/10.3390/molecules24050989 - 11 Mar 2019
Cited by 3Correction
Abstract
Olaparib, an orally active inhibitor of poly(ADP-ribose)polymerase(PARP), is the drug of choice in the treatment of gBRCA1/2+ metastatic breast cancers. Unfortunately, Olaparib is poorly soluble with low bioavailability and tumor accumulation; nano-delivery could be a good choice to overcome these disadvantages. Here, a [...] Read more.
Olaparib, an orally active inhibitor of poly(ADP-ribose)polymerase(PARP), is the drug of choice in the treatment of gBRCA1/2+ metastatic breast cancers. Unfortunately, Olaparib is poorly soluble with low bioavailability and tumor accumulation; nano-delivery could be a good choice to overcome these disadvantages. Here, a rapid and robust HPLC-ESI–MS/MS method for the quantification of Olaparib in ferritin nano-carriers led to the development of cells compartments, different tissues, plasma and urines and were validated to assess the effects of nano-delivery on cell compartment distribution of the drug. This method allows the quantification of Olaparib within the linear range of 0.1–10ng/mL in cells culture medium and cell cytoplasm, of 0.5–10ng/mL in nuclei, of 0.5–100ng/mL in plasma and urine and of 10–500ng/mL in tissue samples (kidney and liver). The limit of quantification was found to be 1.54 ng/mL for liver, 2.87 ng/mL for kidney, and lower than 0.48 ng/mL for all matrices. The method has been applied to quantify Ola encapsulated in ferritin-nano-carriers during the nano-drug development. The application of the method to human BRCA-mutated cell model to quantify the Olaparib distribution after incubation of free or ferritin-encapsulated Olaparib is also reported. This sensitive method allows the quantification of low concentrations of Olaparib released from nano-carriers in different cell compartments, leading to the determination of the drug release and kinetic profile of an essential parameter to validate nano-carriers. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessFeature PaperArticle
Anti-Idiotype DNA Aptamer Affinity Purification–High-Temperature Reversed-Phase Liquid Chromatography: A Simple, Accurate, and Selective Bioanalysis of Bevacizumab
Molecules 2019, 24(5), 857; https://doi.org/10.3390/molecules24050857 - 28 Feb 2019
Cited by 2
Abstract
This study presents a simple, accurate, and selective bioanalytical method of bevacizumab detection from plasma samples based on aptamer affinity purification–high-temperature reversed-phased liquid chromatography (HT-RPLC) with fluorescence detection. Bevacizumab in plasma samples was purified using magnetic beads immobilized with an anti-idiotype DNA aptamer [...] Read more.
This study presents a simple, accurate, and selective bioanalytical method of bevacizumab detection from plasma samples based on aptamer affinity purification–high-temperature reversed-phased liquid chromatography (HT-RPLC) with fluorescence detection. Bevacizumab in plasma samples was purified using magnetic beads immobilized with an anti-idiotype DNA aptamer for bevacizumab. The purified bevacizumab was separated with HT-RPLC and detected with its native fluorescence. Using aptamer affinity beads, bevacizumab was selectively purified and detected as a single peak in the chromatogram. HT-RPLC achieved good separation for bevacizumab with a sharp peak within 10 min. The calibration curves of the two monoclonal antibodies ranged from 1 to 50 μg/mL and showed good correlation coefficients (r2 > 0.999). The limit of detection (LOD) and lower limit of quantification (LLOQ) values for bevacizumab were 0.15 and 0.51 μg/mL, respectively. The proposed method was successfully applied to the bioanalysis of the plasma samples obtained from the patients with lung cancer and may be extended to plan optimal therapeutic programs and for the evaluation of biological equivalencies in the development of biosimilars. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Optimisation of Protein Extraction from Medicinal Cannabis Mature Buds for Bottom-Up Proteomics
Molecules 2019, 24(4), 659; https://doi.org/10.3390/molecules24040659 - 13 Feb 2019
Cited by 7
Abstract
Medicinal cannabis is used to relieve the symptoms of certain medical conditions, such as epilepsy. Cannabis is a controlled substance and until recently was illegal in many jurisdictions. Consequently, the study of this plant has been restricted. Proteomics studies on Cannabis sativa reported [...] Read more.
Medicinal cannabis is used to relieve the symptoms of certain medical conditions, such as epilepsy. Cannabis is a controlled substance and until recently was illegal in many jurisdictions. Consequently, the study of this plant has been restricted. Proteomics studies on Cannabis sativa reported so far have been primarily based on plant organs and tissues other than buds, such as roots, hypocotyl, leaves, hempseeds and flour. As far as we know, no optimisation of protein extraction from cannabis reproductive tissues has been attempted. Therefore, we set out to assess different protein extraction methods followed by mass spectrometry-based proteomics to recover, separate and identify the proteins of the reproductive organs of medicinal cannabis, apical buds and isolated trichomes. Database search following shotgun proteomics was limited to protein sequences from C. sativa and closely related species available from UniprotKB. Our results demonstrate that a buffer containing the chaotrope reagent guanidine hydrochloride recovers many more proteins than a urea-based buffer. In combination with a precipitation with trichloroacetic acid, such buffer proved optimum to identify proteins using a trypsin digestion followed by nano-liquid chromatography tandem mass spectrometry (nLC-MS/MS) analyses. This is validated by focusing on enzymes involved in the phytocannabinoid pathway. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Simultaneous Detection of Carnosine and Anserine by UHPLC-MS/MS and Its Application on Biomarker Analysis for Differentiation of Meat and Bone Meal
Molecules 2019, 24(2), 217; https://doi.org/10.3390/molecules24020217 - 09 Jan 2019
Cited by 3
Abstract
A novel ultra-high performance liquid chromatography (UHPLC) procedure, coupled with tandem mass spectrometry (MS/MS), was established for the analysis of anserine (ANS) and carnosine (CAR) in meat and bone meal (MBM) (bovine, ovine, porcine, and poultry origins). The pretreatment strategies were optimized for [...] Read more.
A novel ultra-high performance liquid chromatography (UHPLC) procedure, coupled with tandem mass spectrometry (MS/MS), was established for the analysis of anserine (ANS) and carnosine (CAR) in meat and bone meal (MBM) (bovine, ovine, porcine, and poultry origins). The pretreatment strategies were optimized for four types of MBM samples prior to UHPLC-MS/MS analysis. This method allowed determining CAR and ANS in short analysis time (18 min per sample). The limits of detection (LODs) and limits of quantification (LOQs) of two analytes in four types of MBM samples were in the ranges of 0.41–3.07 ng/g and 0.83–5.71 ng/g, respectively. The recovery rates spiked with low, intermediate, and high levels of two analytes in four types of MBM samples were 48.53–98.93%, 60.12–98.94%, and 67.90–98.92%, respectively. Acceptable inter-day reproducibility (RSD < 12.63%) supported the application of this proposed method for determining CAR and ANS in MBM samples. Overall, this rapid, effective, and robust method was successfully applied for quantitative detection of CAR and ANS in MBM samples. Furthermore, The CAR/ANS ratio was found to be in the decreasing order: porcine > bovine > ovine > poultry MBM. This proposed methodology was novelly applied to identify the biomarker (CAR/ANS ratio) for species-specific identification of MBM. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Simultaneous Determination of Five Phenolic Acids and Four Flavonoid Glycosides in Rat Plasma Using HPLC-MS/MS and Its Application to a Pharmacokinetic Study after a Single Intravenous Administration of Kudiezi Injection
Molecules 2019, 24(1), 64; https://doi.org/10.3390/molecules24010064 - 25 Dec 2018
Cited by 7
Abstract
This study has developed a reliable and precise high performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of five phenolic acids and four flavonoid glycosides in rat plasma after a single intravenous administration of Kudiezi injection (KI). Chromatographic separation was carried [...] Read more.
This study has developed a reliable and precise high performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of five phenolic acids and four flavonoid glycosides in rat plasma after a single intravenous administration of Kudiezi injection (KI). Chromatographic separation was carried out on an Ultimate®XB-C18 column (4.6 × 100 mm, 3.5 μm) using a gradient elution program with a mobile phase consisting of water containing 0.5% acetic acid and acetonitrile at a flow rate of 0.6 mL/min. Detection was performed on a triple-quadrupole tandem mass spectrometry using multiple reaction monitoring in negative electrospray ionization mode. The calibration curves of all analytes showed good linearity (R2 > 0.990). The results of selectivity, intra-day and inter-day precisions, extraction recoveries, matrix effects and stability were satisfactory. Pharmacokinetic parameters showed that luteolin-7-O-β-d-gentiobioside, luteolin-7-O-β-d-glucuronide, luteolin-7-O-β-d-glucoside and apigenin-7-O-β-d-glucuronide were eliminated quickly (0.07 h < t1/2 < 0.66 h), whereas 5-caffeoylquinic acid, caftaric acid, chlorogenic acid, 4-caffeoylquinic acid and caffeic acid were eliminated relatively slowly (2.22 h < t1/2 < 6.09 h) in rat blood. The pharmacokinetic results would be valuable to identify bioactive constituents, elucidate mechanisms of pharmacological actions or adverse drug reactions and guide the rational clinical use of KI. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Quantification of 1,3-olein-2-palmitin (OPO) and Palmitic Acid in sn-2 Position of Triacylglycerols in Human Milk by Liquid Chromatography Coupled with Mass Spectrometry
Molecules 2019, 24(1), 22; https://doi.org/10.3390/molecules24010022 - 21 Dec 2018
Cited by 1
Abstract
This study describes the identification and quantification of fatty acids in the sn-2 position of triacylglycerols (TAG) and of the most abundant TAG regioisomers in human milk by liquid chromatography coupled with high-resolution mass spectrometry (HPLC-HRMS). Over 300 individual TAG species were [...] Read more.
This study describes the identification and quantification of fatty acids in the sn-2 position of triacylglycerols (TAG) and of the most abundant TAG regioisomers in human milk by liquid chromatography coupled with high-resolution mass spectrometry (HPLC-HRMS). Over 300 individual TAG species were observed and 1,3-olein-2-palmitin (OPO) was identified as the most abundant TAG regioisomer. Validation of the HPLC-HRMS method showed repeatability and intermediate reproducibility values ranging from 3.1 to 16.6% and 4.0 to 20.7%, respectively, and accuracy ranging from 75 to 97%. Results obtained by the HPLC-HRMS method were comparable to results from the ISO 6800 method for the quantification of palmitic acid in the sn-2 position of TAG (81.4 and 81.8 g 100 g−1 total palmitic acid, respectively). Processing the data obtained with the HPLC-HRMS method is extremely time consuming and, therefore, a targeted method suitable for the quantification of OPO in human milk samples by ultra-performance (UP) LC coupled with triple quadrupole (QQQ) MS was developed and validated. OPO identification and quantification by UPLC-QQQ were based on nominal mass and a fragmentation pattern obtained by multiple reaction monitoring experiments. The method was validated in terms of accuracy and precision by analyzing different aliquots of the same human milk sample over time and comparing the results with values obtained by HPLC-HRMS. Intermediate reproducibility was <15% and trueness comparable to HPLC-HRMS. Quantification of OPO in human milk samples collected at 30, 60 and 120 days postpartum showed that OPO content varies between 333 ± 11.8 and 383 ± 18.0 mg 100mL−1. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Metabolomics of Solanum lycopersicum Infected with Phytophthora infestans Leads to Early Detection of Late Blight in Asymptomatic Plants
Molecules 2018, 23(12), 3330; https://doi.org/10.3390/molecules23123330 - 15 Dec 2018
Cited by 9
Abstract
Tomato crops suffer attacks of various pathogens that cause large production losses. Late blight caused by Phytophthora infestans is a devastating disease in tomatoes because of its difficultly to control. Here, we applied metabolomics based on liquid chromatography–mass spectrometry (LC-MS) and metabolic profiling [...] Read more.
Tomato crops suffer attacks of various pathogens that cause large production losses. Late blight caused by Phytophthora infestans is a devastating disease in tomatoes because of its difficultly to control. Here, we applied metabolomics based on liquid chromatography–mass spectrometry (LC-MS) and metabolic profiling by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) in combination with multivariate data analysis in the early detection of late blight on asymptomatic tomato plants and to discriminate infection times of 4, 12, 24, 36, 48, 60, 72 and 96 h after inoculation (hpi). MALDI-MS and LC-MS profiles of metabolites combined with multivariate data analysis are able to detect early-late blight-infected tomato plants, and metabolomics based on LC-MS discriminates infection times in asymptomatic plants. We found the metabolite tomatidine as an important biomarker of infection, saponins as early infection metabolite markers and isocoumarin as early and late asymptomatic infection marker along the post infection time. MALDI-MS and LC-MS analysis can therefore be used as a rapid and effective method for the early detection of late blight-infected tomato plants, offering a suitable tool to guide the correct management and application of sanitary defense approaches. LC-MS analysis also appears to be a suitable tool for identifying major metabolites of asymptomatic late blight-infected tomato plants. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Rapid Characterization and Identification of Chemical Constituents in Gentiana radix before and after Wine-Processed by UHPLC-LTQ-Orbitrap MSn
Molecules 2018, 23(12), 3222; https://doi.org/10.3390/molecules23123222 - 06 Dec 2018
Cited by 5
Abstract
Gentiana radix is used in traditional Chinese medicine and has functions of clearing heat and drying dampness, as well as purging liver and gallbladder fire. A highly sensitive and effective strategy for rapid screening and identification of target constituents has been developed by [...] Read more.
Gentiana radix is used in traditional Chinese medicine and has functions of clearing heat and drying dampness, as well as purging liver and gallbladder fire. A highly sensitive and effective strategy for rapid screening and identification of target constituents has been developed by using ultra high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap) in crude and wine-processed Gentiana radix. Based on the accurate mass measurement (<5 ppm), retention times, and MS fragmentation ions, 52 constituents were unambiguously or tentatively characterized from Gentiana radix, including 21 iridoids, 11 flavonoids, 19 xanthones, and a triterpenoid. This study demonstrated that the established method could be a rapid, effective analytical tool for screening and characterization of compounds in the complex systems of Gentiana radix. By comparing the structure and peak areas of chemical constituents in crude and wine-processed Gentiana radix, we found that some compounds in crude and wine-processed Gentiana radix were significantly different. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Determination of Tranquilizers in Swine Urine by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry
Molecules 2018, 23(12), 3215; https://doi.org/10.3390/molecules23123215 - 05 Dec 2018
Cited by 1
Abstract
A rapid, reliable, and sensitive method was developed for the determination of ten tranquilizers in swine urine. Sample preparation was based on solid-phase extraction, which combined isolation of the compounds and sample cleanup in a single step. Separation was performed on a reversed [...] Read more.
A rapid, reliable, and sensitive method was developed for the determination of ten tranquilizers in swine urine. Sample preparation was based on solid-phase extraction, which combined isolation of the compounds and sample cleanup in a single step. Separation was performed on a reversed phase C18 column by gradient elution with a chromatographic run time of seven minutes, consisting of 0.1% formic acid in water and acetonitrile as the mobile phase. Multiple reaction monitoring in positive mode was applied for data acquisition. Matrix-matched calibration was used for quantification and good linearity was obtained with coefficients of determination higher than 0.99. The average recoveries of fortified samples at concentrations between 0.05 and 10 µg/L ranged from 85% to 106% with interday relative standard deviations of less than 13% in all cases. The limits of detection and limits of quantification obtained for tranquilizers in the urine were in the ranges of 0.03–0.1 µg/L and 0.05–0.25 µg/L, respectively. The applicability of the proposed method was demonstrated by analyzing real samples; diazepam was detected at concentrations between 0.3 and 0.6 μg/L. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Intracellular Accumulation of Linezolid and Florfenicol in OptrA-Producing Enterococcus faecalis and Staphylococcus aureus
Molecules 2018, 23(12), 3195; https://doi.org/10.3390/molecules23123195 - 04 Dec 2018
Cited by 5
Abstract
The optrA gene, which confers transferable resistance to oxazolidinones and phenicols, is defined as an ATP-binding cassette (ABC) transporter but lacks transmembrane domains. The resistance mechanism of optrA and whether it involves antibiotic efflux or ribosomal protection remain unclear. In this study, we [...] Read more.
The optrA gene, which confers transferable resistance to oxazolidinones and phenicols, is defined as an ATP-binding cassette (ABC) transporter but lacks transmembrane domains. The resistance mechanism of optrA and whether it involves antibiotic efflux or ribosomal protection remain unclear. In this study, we determined the MIC values of all bacterial strains by broth microdilution, and used ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry to quantitatively determine the intracellular concentrations of linezolid and florfenicol in Enterococcus faecalis and Staphylococcus aureus. Linezolid and florfenicol both accumulated in susceptible strains and optrA-carrying strains of E. faecalis and S. aureus. No significant differences were observed in the patterns of drug accumulation among E. faecalis JH2-2, E. faecalis JH2-2/pAM401, and E. faecalis JH2-2/pAM401+optrA, but also among S. aureus RN4220, S. aureus RN4220/pAM401, and S. aureus RN4220/pAM401+optrA. ANOVA scores also suggested similar accumulation conditions of the two target compounds in susceptible strains and optrA-carrying strains. Based on our findings, the mechanism of optrA-mediated resistance to oxazolidinones and phenicols obviously does not involve active efflux and the OptrA protein does not confer resistance via efflux like other ABC transporters. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Rapid HPLC-ESI-MS/MS Analysis of Neurotransmitters in the Brain Tissue of Alzheimer’s Disease Rats before and after Oral Administration of Xanthoceras sorbifolia Bunge
Molecules 2018, 23(12), 3111; https://doi.org/10.3390/molecules23123111 - 28 Nov 2018
Cited by 1
Abstract
In order to explore the potential therapeutic effect of Xanthoceras sorbifolia Bunge. against Alzheimer’s disease, an HPLC-MS/MS method has been developed and validated for simultaneous determination in rat brain of eight neurotransmitters, including dopamine, norepinephrine, 5-hydroxy-tryptamine, acetylcholine, l-tryptophan, γ-aminobutyric acid, glutamic acid [...] Read more.
In order to explore the potential therapeutic effect of Xanthoceras sorbifolia Bunge. against Alzheimer’s disease, an HPLC-MS/MS method has been developed and validated for simultaneous determination in rat brain of eight neurotransmitters, including dopamine, norepinephrine, 5-hydroxy-tryptamine, acetylcholine, l-tryptophan, γ-aminobutyric acid, glutamic acid and aspartic acid with a simple protein precipitation method for sample pre-treatment. The brain samples were separated on a polar functional group embedded column, then detected on a 4000 QTrap HPLC-MS/MS system equipped with a turbo ion spray source in positive ion and multiple reaction monitoring mode. The method was fully validated to be precise and accurate within the linearity range of the assay, and successfully applied to compare the neurotransmitters in the rat brain from four groups of normal, Alzheimer’s disease, and the oral administration group of X. sorbifolia extract and huperzine. The results indicated that brain levels of dopamine, norepinephrine and acetyl choline all decreased in the AD rats, while l-tryptophan showed an opposite trend. After administration of the Xanthoceras sorbifolia extract and huperzine, the level of acetyl choline and tryptophan returned to normal. Combination of the metabolic analysis, the results indicated that acetyl choline and l-tryptophan could be employed as therapy biomarkers for AD, and the results shown that the crude extract of the husks from Xanthoceras sorbifolia might ameliorate the impairment of learning and memory in the Alzheimer’s disease animal model with similar function of AchEI as huperzine. The established method would provide an innovative and effective way for the discovery of novel drug against Alzheimer’s disease, and stimulate a theoretical basis for the design and development of new drugs. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Determination of Tryptophan and Its Major Metabolites in Fluid from the Anterior Chamber of the Eye in Diabetic Patients with Cataract by Liquid Chromotography Mass Spectrometry (LC-MS/MS)
Molecules 2018, 23(11), 3012; https://doi.org/10.3390/molecules23113012 - 17 Nov 2018
Cited by 3
Abstract
Tryptophan (TRP) is to an essential amino acid and its catabolites are significant to human health. By using ultra-high-performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS), levels of three major components of kynurenic pathway namely tryptophan (TRP), kynurenic acid [...] Read more.
Tryptophan (TRP) is to an essential amino acid and its catabolites are significant to human health. By using ultra-high-performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS), levels of three major components of kynurenic pathway namely tryptophan (TRP), kynurenic acid (KYNA) and kynurenine (KYN) in fluid from the anterior chamber of the eye were determined. The analysis was carried out on a Synergi 4 μ Fusion-RP column using gradient elution mode. For quantitative determination, l-tryptophan-amino-15N, 99 ATOM % 15N was used as an internal standard. The method was linear in the concentration range 4–2000 ng mL−1 for TRP, KYNA and KYN. The mean recoveries measured at four concentration levels for TRP, KYN and KYNA included the following ranges 94.3–96.1; 91.0–95.0; and 96.0–97.6%, respectively. The intra-day precision parameters were smaller than 4.4, 6.4 and 5% respectively. The developed method was applied to study the level of TRP, KYNA and KYN in eye fluid for the retrospective case series which included 28 patients suffering from cataracts and diabetes (n = 8). The experimental data was subjected to statistical analysis. The Mann-Whitney U-test revealed clear differences in the level of TRP catabolites and the ratios of TRP/KYN representing the activities of specific enzyme of kynurenine pathway in examined groups of patients. A level of probability p < 0.05 was used throughout a paper to denote statistically significant differences between the groups. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Open AccessArticle
Integrated Proteomics and Lipidomics Investigation of the Mechanism Underlying the Neuroprotective Effect of N-benzylhexadecanamide
Molecules 2018, 23(11), 2929; https://doi.org/10.3390/molecules23112929 - 09 Nov 2018
Cited by 2
Abstract
Macamides are very important secondary metabolites produced by Lepidium meyenii Walp, which possess multiple bioactivities, especially in the neuronal system. In a previous study, we observed that macamides exhibited excellent effects in the recovery of injured nerves after 1-methyl-4-phenylpyridinium (MPP+)-induced dopaminergic [...] Read more.
Macamides are very important secondary metabolites produced by Lepidium meyenii Walp, which possess multiple bioactivities, especially in the neuronal system. In a previous study, we observed that macamides exhibited excellent effects in the recovery of injured nerves after 1-methyl-4-phenylpyridinium (MPP+)-induced dopaminergic neuronal damage in zebrafish. However, the mechanism underlying this effect remains unclear. In the present study, we observed that N-benzylhexadecanamide (XA), which is a typical constituent of macamides, improved the survival rate of neurons in vitro. We determined the concentration of neurotransmitters in MN9D cells and used it in conjunction with an integrated proteomics and lipidomics approach to investigate the mechanism underlying the neuroprotective effects of XA in an MPP+-induced neurodegeneration cell model using QqQ MS, Q-TOF MS, and Orbitrap MS. The statistical analysis of the results led to the identification of differentially-expressed biomarkers, including 11 proteins and 22 lipids, which may be responsible for the neuron-related activities of XA. All these potential biomarkers were closely related to the pathogenesis of neurodegenerative diseases, and their levels approached those in the normal group after treatment with XA. Furthermore, seven lipids, including five phosphatidylcholines, one lysophosphatidylcholine, and one phosphatidylethanolamine, were verified by a relative quantitative approach. Moreover, four proteins (Scarb2, Csnk2a2, Vti1b, and Bnip2) were validated by ELISA. The neurotransmitters taurine and norepinephrine, and the cholinergic constituents, correlated closely with the neuroprotective effects of XA. Finally, the protein–lipid interaction network was analyzed. Based on our results, the regulation of sphingolipid metabolism and mitochondrial function were determined to be the main mechanisms underlying the neuroprotective effect of XA. The present study should help us to better understand the multiple effects of macamides and their use in neurodegenerative diseases. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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Hair Metabolomics in Animal Studies and Clinical Settings
Molecules 2019, 24(12), 2195; https://doi.org/10.3390/molecules24122195 - 12 Jun 2019
Cited by 1
Abstract
Metabolomics is a powerful tool used to understand comprehensive changes in the metabolic response and to study the phenotype of an organism by instrumental analysis. It most commonly involves mass spectrometry followed by data mining and metabolite assignment. For the last few decades, [...] Read more.
Metabolomics is a powerful tool used to understand comprehensive changes in the metabolic response and to study the phenotype of an organism by instrumental analysis. It most commonly involves mass spectrometry followed by data mining and metabolite assignment. For the last few decades, hair has been used as a valuable analytical sample to investigate retrospective xenobiotic exposure as it provides a wider window of detection than other biological samples such as saliva, plasma, and urine. Hair contains functional metabolomes such as amino acids and lipids. Moreover, segmental analysis of hair based on its growth rate can provide information on metabolic changes over time. Therefore, it has great potential as a metabolomics sample to monitor chronic diseases, including drug addiction or abnormal conditions. In the current review, the latest applications of hair metabolomics in animal studies and clinical settings are highlighted. For this purpose, we review and discuss the characteristics of hair as a metabolomics sample, the analytical techniques employed in hair metabolomics and the consequence of hair metabolome alterations in recent studies. Through this, the value of hair as an alternative biological sample in metabolomics is highlighted. Full article
(This article belongs to the Special Issue Biological Sample Analysis by Liquid Chromatography)
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