Modified Jiu Wei Qiang Huo decoction improves dysfunctional metabolomics in influenza A pneumonia‐infected mice

In order to study the effective mechanism of a traditional Chinese medicine (TCM), modified Jiu Wei Qiang Huo decoction (MJWQH), against H1N1‐induced pneumonia in mice, we chose a holistic approach. A reverse‐phase liquid chromatography with quadruple time‐of‐flight mass spectrometry (LC‐Q‐TOF‐MS) was developed to determine metabolomic biomarkers in mouse serum for the MJWQH effects. Thirteen biomarkers of H1N1‐induced pneumonia in mice serum were identified, which comprised l ‐valine, lauroylcarnitine, palmitoyl‐l ‐carnitine, l ‐ornithine, uric acid, taurine, O‐succinyl‐l ‐homoserine, l ‐leucine, l ‐phenylalanine, PGF2α, 20‐ethyl‐PGE2, arachidonic acid, and glycerophospho‐N‐arachidonoyl ethanolamine. Among them, metabolites of amino acids, fatty acids and arachidonic acid had the most relevant changes in mice with H1N1‐induced pneumonia. MJWQH effectively improved weight loss, lung index, biomarkers and inflammatory mediators such as prostaglandin E2 and phospholipase A2 in the infected mice. Importantly, MJWQH reversed the elevated biomarkers to the control levels from the infection, which provided a systematic view and a theoretical basis for its prevention or treatment. The results suggest that the protective effect of MJWQH against H1N1‐induced pneumonia is possibly through regulation of pathways for amino acid, fatty acid and arachidonic acid metabolism. They also suggest that the LC‐MS‐based metabolomic strategy is a powerful tool for elucidation of the mechanisms of TCM. Copyright © 2013 John Wiley & Sons, Ltd.     

Metabolic alterations in triptolide‐induced acute hepatotoxicity

Triptolide, a major active constitute of Tripterygium wilfordii Hook. F, is prescribed for the treatment of autoimmune diseases in China. One of its most severe adverse effects observed in the clinical use is hepatotoxicity, but the mechanism is still unknown. Therefore, the present study applied an LC/MS‐based metabolomic analysis to characterize the metabolomic changes in serum and liver induced by triptolide in mice. Mice were administered triptolide by gavage to establish the acute liver injury model, and serum biochemical and liver histological analyses were applied to assess the degree of toxicity. Multivariate data analyses were performed to investigate the metabolic alterations. Potential metabolites were identified using variable importance in the projection values and Student's t‐test. A total of 30 metabolites were observed that were significantly changed by triptolide treatment and the abundance of 29 metabolites was correlated with the severity of toxicity. Pathway analysis indicated that the mechanism of triptolide‐induced hepatotoxicity was related to alterations in multiple metabolic pathways, including glutathione metabolism, tricarboxylic acid cycle, purine metabolism, glycerophospholipid metabolism, taurine and hypotaurine metabolism, pantothenate and CoA biosynthesis, pyrimidine metabolism and amino acid metabolism. The current study provides new mechanistic insights into the metabolic alterations that lead to triptolide‐induced hepatotoxicity.     

Combination of HPLC with organic and inorganic mass spectrometry to study the metabolic response of the clam Scrobicularia plana to arsenic exposure

Arsenic is a toxic element extensively studied in the marine environment due to differential toxicological effects of inorganic and organic species. In the present work, the bivalve Scrobicularia plana was exposed to As^V (10 and 100 μg/L) for 14 days to evaluate the metabolic perturbations caused by this element. Arsenic speciation and metabolomic analysis were performed in the digestive gland of the bivalve using two complementary analytical platforms based on inorganic and organic mass spectrometry. It has been observed the greater presence of the innocuous specie arsenobetaine produced in this organism as defense mechanism against arsenic toxicity, although significant concentrations of methylated and inorganic arsenic were also present, depending on the level of arsenic in aqueous media. Complementarily, a metabolomic study based on mass spectrometry and statistical discriminant analysis allows a good classification of samples associated to low and high As(V) exposure in relation to controls. About 15 metabolites suffer significant changes of expression by the presence of As(V): amino acids, nucleotides, energy‐related metabolites, free fatty acids, phospholipids and triacylglycerides, which can be related to membrane structural and functional damage. In addition, perturbation of the methylation cycle, associated with the increase of homocysteine and methionine was observed, which enhance the methylation of toxic inorganic arsenic to less toxic dimethylarsenic.     

Metabolic effects of Hedyotis diffusa on rats bearing Walker 256 tumor revealed by NMR‐based metabolomics

Hedyotis diffusa, a traditional Chinese herbal medicine, is widely used for oncotherapy and shows a positive effect in the clinical treatment. But its mechanism of anticancer activities is complicated and unclear. This study was undertaken to assess the therapeutic effects and reveal detailed mechanisms of H. diffusa for oncotherapy. A Walker 256 tumor‐bearing rat model was established, and metabolomic profiles of plasma and urine were obtained from ¹H NMR technique. Multivariate statistical analysis methods were used to characterize the discriminating metabolites between control (C), Walker 256 tumor‐bearing rats model (M), and H. diffusa treatment (H) groups. Finally, 13 and 10 metabolomic biomarkers in urine and plasma samples were further identified as characteristic metabolites in M group, whereas H group showed a partial metabolic balance recovered, such as ornithine, N‐acetyl‐l ‐aspartate, l ‐aspartate, and creatinine in urine samples, and acetate, lactate, choline, l ‐glutamine, and 3‐hydroxybutyrate in plasma samples. On the basis of the methods above, we hypothesized H. diffusa treatment reduced the injury caused by Walker 256 tumor and maintained a metabolic balance. Our study demonstrated that this method provided new insights into metabolic alterations in tumor‐bearing biosystems and researching on the effects of H. diffusa on the endogenous metabolism in tumor‐bearing rats.     

Gas chromatography/time‐of‐flight mass spectrometry‐based metabonomics of hepatocarcinoma in rats with lung metastasis: elucidation of the metabolic characteristics of hepatocarcinoma at formation and metastasis

Hepatocarcinoma (HCC) has a very high mortality rate and the high recurrence and metastasis rates contribute to the poor prognosis of HCC patients. To understand HCC formation and metastasis, we assessed the metabonomics of rat HCC and HCC with lung metastasis (HLM). The HLM rat model was established by exposure to diethylnitrosamine (DEN). Levels of serum and urine metabolites were quantified with gas chromatography/time‐of‐flight mass spectrometry (GC/TOFMS), and data were analyzed with partial least‐squares discrimination analysis (PLS‐DA). Serum and urine levels of some metabolites differed significantly between the control, HCC, and HLM groups. The products and intermediates from glycolysis and glutamate metabolism were elevated, while the tricarboxylic acid (TCA) cycle was inhibited, in both HCC and HLM. HLM samples revealed enhanced metabolism of nucleic acids, amino acids and glucuronic acid. PLS‐DA indicated that principal component weighting was greatest for serum serine, phenylalanine, lactic acid, tyrosine and glucuronic acid, and urine glycine, serine, 5‐oxyproline, malate, hippuric acid and uric acid. These data provide novel information that will improve understanding of the pathophysiological processes involved in HCC and HLM, and revealed potential metabolic markers for HCC invasion and metastasis. Copyright © 2010 John Wiley & Sons, Ltd.     

Metabolomics reveals significant impairments in the immune system of the APP/PS1 transgenic mice of Alzheimer's disease

Inflammatory processes and other failures related to the immune system are common features associated with Alzheimer's disease (AD), in both brain and the peripheral system. Thus, the study of the main organs of the immune system may have a great potential for the elucidation of pathological mechanisms underlying these abnormalities. This is the first metabolomic investigation performed in spleen and thymus from transgenic mice of AD. Tissues were fingerprinted using a metabolomic platform comprising GC‐MS and ultra‐HPLC‐MS. Multivariate statistics demonstrated significant differences in numerous metabolites between the APP/PS1 mice and wild‐type controls, and it was proven that multiple biochemical pathways are disturbed in these organs including abnormal metabolism of phospholipids, energy deficiencies, altered homeostasis of amino acids, oxidative stress, and others. Therefore, these findings highlight the importance of the proper metabolic functioning of peripheral immune system in the development of neurodegenerative disorders such as AD.     

A metabolomic strategy to screen the prototype components and metabolites of Qingkailing injection in rat urine by high‐performance liquid chromatography with tandem mass spectrometry

Xenobiotic metabolome identification of Chinese herbal formula in biological systems is a very challenging task. Qingkailing injection is a typical Chinese herbal injection, which is wildly used clinically in China. However, the holistic metabolic fate of the ingredient from Qingkailing injection remains unclear. In this work, a metabolomic strategy for comprehensively elucidating Qingkailing injection derived prototype components and metabolites in rat urine conducted by hybrid linear ion trap high‐resolution mass spectrometry was developed. High‐performance liquid chromatography coupled with hybrid linear ion trap high‐resolution mass spectrometry was developed to obtain the urine profiling between the control group and Qingkailing injection treated group. Orthogonal partial least squares discriminate analysis was applied to distinguish the exogenous and the endogenous. In the S‐plot, 37 xenobiotics derived from Qingkailing injection were found in urine, including 18 prototype compounds and 19 metabolites. The characterization of the prototype components and metabolites in rat's urine provided essential data for further pharmacological studies of Qingkailing injection. Our results indicated that the metabolomic approach was an effective tool to discover, screen, and analyze the multiple prototype components and their metabolites from complicated traditional Chinese preparations in vivo.     

Liquid chromatography/mass spectrometry for investigating the biochemical effects induced by aristolochic acid in rats: the plasma metabolome

In this study, high‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry in conjunction with chemometric methods including principal components analysis was used to investigate metabolic profiling in plasma samples from rats dosed with aristolochic acid (AA). Differentiating metabolites were identified by high‐resolution mass spectrometry and tandem mass spectrometry analyses, database searching and comparison with the analytical results of authentic standards. Several metabolites in plasma including a glucuronide conjugate, bile acids, lysophosphatidylcholines and fatty acids were detected in rats exposed to AA. To improve visualization, a z‐score plot and a cluster heat map were generated for the concentration fluctuations of the metabolites in different dosage groups. The results obtained from this study indicated that class‐specific metabolomic patterns were obviously differentiated for each metabolite in the different dosage groups of AA. Copyright © 2010 John Wiley & Sons, Ltd.     

Metabonomic analysis of serum reveals antifatigue effects of Yi Guan Jian on fatigue mice using gas chromatography coupled to mass spectrometry

Yi Guan Jian (YGJ), one of the most commonly used traditional Chinese medicines, has been reported to possess significant antifatigue effects. However, the mechanisms underlying its antifatigue effects remain largely unresolved. In this study, a metabonomics approach, involving gas chromatography coupled to mass spectrometry and a multivariate statistical technique, was developed to estimate the extent to which YGJ alleviated the exhausting swimming‐induced fatigue of mice. High‐dose treatment with YGJ significantly extended the swimming time of fatigued mice. Significant alterations of metabolites involving amino acids, organic acids and carbohydrates were observed in the serum of fatigued mice, which were reversed by YGJ treatment while biochemical indexes returned to normal. These metabolic changes suggest that the antifatigue effect of YGJ is associated with the impairement of amino acid, organic acids and carbohydrates. It also appears that YGJ can induce significant metabolic alterations independent of the exhausting swimming‐induced metabolic changes. The significantly altered metabolites induced by YGJ intervention include l‐ 2‐amino‐acetoacetate, taurine, fumaric acid, malic acid, oxoadipic acid and l‐ aspartate, all of which are associated with antifatigue properties. This suggests that YGJ exerts chemopreventive effects via antifatigue mechanisms.     

Serum metabolomics as a novel diagnostic approach for gastrointestinal cancer

Conventional tumor markers are unsuitable for detecting carcinoma at an early stage and lack clinical efficacy and utility. In this study, we attempted to investigate the differences in serum metabolite profiles of gastrointestinal cancers and healthy volunteers using a metabolomic approach and searched for sensitive and specific metabolomic biomarker candidates. Human serum samples were obtained esophageal (n = 15), gastric (n = 11), and colorectal (n = 12) cancer patients and healthy volunteers (n = 12). A model for evaluating metabolomic biomarker candidates was constructed using multiple classification analysis, and the results were assessed with receiver operating characteristic curves. Among the 58 metabolites, the levels of nine, five and 12 metabolites were significantly changed in the esophageal, gastric and colorectal cancer patients, respectively, compared with the healthy volunteers. Multiple classification analysis revealed that the variations in the levels of malonic acid and l ‐serine largely contributed to the separation of esophageal cancer; gastric cancer was characterized by changes in the levels of 3‐hydroxypropionic acid and pyruvic acid; and l ‐alanine, glucuronoic lactone and l ‐glutamine contributed to the separation of colorectal cancer. Our approach revealed that some metabolites are more sensitive for detecting gastrointestinal cancer than conventional biomarkers. Our study supports the potential of metabolomics as an early diagnostic tool for cancer. Copyright © 2011 John Wiley & Sons, Ltd.     

Hepatoprotective Effects of Ixeris chinensis on Nonalcoholic Fatty Liver Disease Induced by High-Fat Diet in Mice: An Integrated Gut Microbiota and Metabolomic Analysis

Ixeris chinensis (Thunb.) Nakai (IC) is a folk medicinal herb used in Mongolian medical clinics for the treatment of hepatitis and fatty liver diseases even though its pharmacological mechanism has not been well characterized. This study investigated the hepatoprotective mechanism of IC on mice with nonalcoholic fatty liver disease (NAFLD) by integrating gut microbiota and metabolomic analysis. A high-fat diet (HFD) was used to develop nonalcoholic fatty liver disease, after which the mice were treated with oral IC (0.5, 1.5 and 3.0 g/kg) for 10 weeks. HFD induced NAFLD and the therapeutic effects were characterized by pathological and histological evaluations, and the serum indicators were analyzed by ELISA. The gut microbial and metabolite profiles were studied by 16S rRNA sequencing and untargeted metabolomic analysis, respectively. The results showed that the administration of IC resulted in significant decreases in body weight; liver index; serum biomarkers such as ALT, TG, and LDL-C; and the liver inflammatory factors IL-1β, IL-6, and TNF-α. The 16S rRNA sequencing results showed that administration of IC extract altered both the composition and abundance of the gut microbiota. Untargeted metabolomic analysis of liver samples detected a total of 212 metabolites, of which 128 were differentially expressed between the HFD and IC group. IC was found to significantly alter the levels of metabolites such as L-glutamic acid, pyridoxal, ornithine, L-aspartic acid, D-proline, and N4-acetylaminobutanal, which are involved in the regulation of glutamine and glutamate, Vitamin B6 metabolism, and arginine and proline metabolic pathways. Correlation analysis indicated that the effects of the IC extract on metabolites were associated with alterations in the abundance of Akkermansiaceae, Lachnospiraceae, and Muribaculaceae. Our study revealed that IC has a potential hepatoprotective effect in NAFLD and that its function might be linked to improvements in the composition of gut microbiota and their metabolites.     

Targeted Metabolomics of Dried Blood Spot Extracts

Dried blood spot (DBS) samples are already successfully used in newborn screening and pharmacological analyses. The application of DBS matrix to further metabolomic methods will considerably extend the analytical options for the diagnostics of metabolic diseases. We present an MS/MS based method for the simultaneous extraction and quantification of 188 metabolites from dried blood spots. We provide a sensitive and reproducible method that adapts the AbsoluteIDQ? p180 kit of Biocrates to the DBS matrix for the quantification of metabolites of different substance classes including amino acids, biogenic amines, free carnitine, acylcarnitines, hexoses, glycerophospholipids, lysophosphatidylcholines, phosphatidylcholines, and sphingolipids.     

Study of plasma metabolic profiling and biomarkers of chronic unpredictable mild stress rats based on gas chromatography/mass spectrometry

A metabolomic investigation of chronic unpredictable mild stress (CUMS) rats was carried out. Plasma obtained from Sprague-Dawley (SD) rats treated by CUMS was analyzed using gas chromatography/mass spectrometry. Thirty-seven metabolites were identified among the detected compounds. Subsequent data analysis using the t test and principal component analysis (PCA) revealed significant metabolic changes in the rats' plasma after CUMS treatment. Clear separation between the model and control group was achieved, and the level of twelve metabolites, including amino acids, sugar, organic acids and fatty acids, were significantly different between plasma samples from the controls and CUMS group. These observations suggested that the depressed state may be associated with perturbation of amino acid metabolism, energy metabolism and glycometabolism. The study suggested that the metabolomics approach could be used as a potential powerful tool to investigate the biochemical change in certain physiopathological conditions, such as depression, as an early diagnostic means.     

Characterization of N‐methylated amino acids by GC‐MS after ethyl chloroformate derivatization

Methylation is an essential metabolic process in the biological systems, and it is significant for several biological reactions in living organisms. Methylated compounds are known to be involved in most of the bodily functions, and some of them serve as biomarkers. Theoretically, all α‐amino acids can be methylated, and it is possible to encounter them in most animal/plant samples. But the analytical data, especially the mass spectral data, are available only for a few of the methylated amino acids. Thus, it is essential to generate mass spectral data and to develop mass spectrometry methods for the identification of all possible methylated amino acids for future metabolomic studies. In this study, all N‐methyl and N,N‐dimethyl amino acids were synthesized by the methylation of α‐amino acids and characterized by a GC‐MS method. The methylated amino acids were derivatized with ethyl chloroformate and analyzed by GC‐MS under EI and methane/CI conditions. The EI mass spectra of ethyl chloroformate derivatives of N‐methyl ( 1–18 ) and N,N‐dimethyl amino acids ( 19–35 ) showed abundant [M‐COOC₂H₅]⁺ ions. The fragment ions due to loss of C₂H₄, CO₂, (CO₂ + C₂H₄) from [M‐COOC₂H₅]⁺ were of structure indicative for 1–18 . The EI spectra of 19–35 showed less number of fragment ions when compared with those of 1–18 . The side chain group (R) caused specific fragment ions characteristic to its structure. The methane/CI spectra of the studied compounds showed [M + H]⁺ ions to substantiate their molecular weights. The detected EI fragment ions were characteristic of the structure that made easy identification of the studied compounds, including isomeric/isobaric compounds. Fragmentation patterns of the studied compounds ( 1–35 ) were confirmed by high‐resolution mass spectra data and further substantiated by the data obtained from ¹³C₂‐labeled glycines and N‐ethoxycarbonyl methoxy esters. The method was applied to human plasma samples for the identification of amino acids and methylated amino acids. Copyright © 2016 John Wiley & Sons, Ltd.     

Targeted metabolomic analysis of 33 amino acids and biogenic amines in human urine by ion‐pairing HPLC‐MS/MS: Biomarkers for tacrolimus nephrotoxicity after renal transplantation

Calcineurin inhibitor nephrotoxicity, especially for the widely used tacrolimus, has become a major concern in post‐transplant immunosuppression. Multiparametric amino acid metabolomics is useful for biomarker identification of tacrolimus nephrotoxicity, for which specific quantitative methods are highlighted as a premise. This article presents a targeted metabolomic assay to quantify 33 amino acids and biogenic amines in human urine by high‐performance liquid chromatography coupled with tandem mass spectrometry. Chromatographic separation was carried out on an Agilent Zorbax SB‐C₁₈ column (3.0 × 150 mm, 5 μm) with addition of an ion‐pairing agent in the mobile phase, and MS/MS detection was achieved in both the positive and negative multiple reaction monitoring modes. Good correlation coefficients (r² > 0.98) were obtained for most analytes. Intra‐ and inter‐day precision, stability, carryover and incurred sample reanalysis met with the acceptance criteria of the guidance of the US Food and Drug Administration. Analysis on urine from healthy volunteers and renal transplantation patients with tacrolimus nephrotoxicity confirmed symmetric dimethylarginine and serine as biomarkers for kidney injury, with AUC values of 0.95 and 0.81 in receiver operating characteristic analysis, respectively. Additionally, symmetric dimethylarginine exhibited a tight correlation with serum creatinine, and was therefore indicative of renal function. The targeted metabolomic assay was time and cost prohibitive for amino acid analysis in human urine, facilitating the biomarker identification of tacrolimus nephrotoxicity.     

ESI‐MS/MS analysis of protonated N‐methyl amino acids and their immonium ions

Methylation is one of the important posttranslational modifications of biological systems. At the metabolite level, the methylation process is expected to convert bioactive compounds such as amino acids, fatty acids, lipids, sugars, and other organic acids into their methylated forms. A few of the methylated amino acids are identified and have been proved as potential biomarkers for several metabolic disorders by using mass spectrometry–based metabolomics workstation. As it is possible to encounter all the N‐methyl forms of the proteinogenic amino acids in plant/biological systems, it is essential to have analytical data of all N‐methyl amino acids for their detection and identification. In earlier studies, we have reported the ESI‐MS/MS data of all methylated proteinogenic amino acids, except that of mono‐N‐methyl amino acids. In this study, the N‐methyl amino acids of all the amino acids ( 1 ‐ 21 ; including one isomeric pair) were synthesized and characterized by ESI‐MS/MS, LC/MS/MS, and HRMS. These data could be useful for detection and identification of N‐methyl amino acids in biological systems for future metabolomics studies. The MS/MS spectra of [M + H]⁺ ions of most N‐methyl amino acids showed respective immonium ions by the loss of (H₂O, CO). The other most common product ions detected were [MH‐(NH₂CH₃]⁺, [MH‐(RH)]⁺ (where R = side chain group) ions, and the selective structure indicative product ions due to side chain and N‐methyl group. The isomeric/isobaric N‐methyl amino acids could easily be differentiated by their distinct MS/MS spectra. Further, the MS/MS of immonium ions inferred side chain structure and methyl group on α‐nitrogen of the N‐methyl amino acids.     

Pressurized CEC coupled with QTOF‐MS for urinary metabolomics

Pressurized CEC (pCEC) coupled with ESI‐QTOF‐MS using a sheathless interface was applied for metabolomics to develop an alternative analytical method for metabolic profiling of complex biofluid samples such as urine. The hyphenated system was investigated with mixed standards and pooled urine samples to evaluate its precision, repeatability, linearity, sensitivity, and selectivity. The applied voltage, mobile phase, and gradient elution were optimized and applied for the analysis of urinary metabolites. Multivariate data analysis was subsequently performed and used to distinguish lung cancer patients from healthy controls successfully. High separation efficiency has been achieved in pCEC due to the EOF. For metabolite identification, the pCEC‐MS separation mechnism was helpful for discriminating the fragment ions of glutamine conjugates from co‐eluted metabolites. Three glutamine conjugates, including phenylacetylglutamine, acylglutamine C8:1, and acylglutamine C6:1 were identified among 16 differential urinary metabolites of lung cancer. Receiver‐operating‐characteristic analysis of acylglutamine C8:1 resulted in an area‐under‐curve value of 0.882. Overall, this work suggests that this pCEC‐ESI‐QTOF‐MS method may provide a novel and useful platform for metabolomic studies due to its superior separation and identification.     

An ultrasonication-assisted extraction and derivatization protocol for GC/TOFMS-based metabolite profiling

Conventional chemical derivatization of metabolites in biological specimens is time-consuming, which limits the throughput and efficiency of metabolite profiling using a gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) platform. We report an ultrasonication-assisted protocol which reduces the derivatization time from hours to about 30 min and significantly enhances the derivatization efficiency prior to a GC/TOFMS analysis. The protocol was evaluated using 40 compounds representing different classes of human metabolites, and demonstrated good analytical precision and accuracy. In comparison with the conventional method, the new protocol was able to increase the intensity of most of the identified peaks (71.0%) in the GC/TOFMS chromatograms of human serum samples. The detected compounds with increased intensity include most amino acids, keto-containing organic acids, carbonyl-containing carbohydrates, and unsaturated fatty acids. We applied this protocol in a metabolomic study of human serum samples obtained from 34 patients diagnosed with hypertension and 29 age- and gender-matched healthy subjects. Metabolite markers associated with hypertension, including glucosamine, D-sorbitol, 1-stearoylglycerol, and homocysteine, were identified and validated by statistical methods and use of reference standards. Our work highlights the potential of this novel approach for the large-scale metabolite profiling of samples generated from plant, animal, and clinical and epidemiological studies.     

Oxygenated Metabolites of n‐3 Polyunsaturated Fatty Acids as Potential Oxidative Stress Biomarkers: Total Synthesis of 8‐F3t‐IsoP, 10‐F4t‐NeuroP and [D4]‐10‐F4t‐NeuroP

A wide variety of metabolic products of polyunsaturated fatty acids is of paramount importance for improving our medical knowledge in the field of oxidized lipids. Two novel metabolites of n‐3 polyunsaturated fatty acids, 8‐F_3t‐IsoP and 10‐F_4t‐NeuroP as well as a deuterated derivative thereof were synthesized based on an acetylenic intermediate. An original approach achieved lateral chain insertion of 8‐F_3t‐IsoP by a ring‐closing alkyne metathesis/semi‐reduction strategy together with a temporary tether.     

Simultaneous determination of thirteen kinds of amino acid and eight kinds of acylcarnitine in human serum by LC–MS/MS and its application to measure the serum concentration of lung cancer patients

Easy‐to‐use early cancer detection methods based on metabolomics using serum samples have been developed recently. Among metabolites, amino acids and acylcarnitine are two of the most suitable candidates for diagnosing lung cancer. The purpose of the present study was to develop a novel, sensitive and specific liquid chromatography–tandem mass spectrometry (LC–MS/MS) method to simultaneously determine 13 amino acids and 8 acylcarnitines in lung cancer patients in serum. After derivatization, the 21 analytes were separated using a C₁₈ column with gradient elution program in 14 min, obtaining recovery within 90.4–113.8% and precision within 0.3–14.8%. The method was successfully applied in concentration determination of lung cancer patients and healthy controls. The results showed that the serum concentration of lung cancer patients were significant from those of healthy controls.