Rapid determination of amino acids in fruits of Ziziphus jujuba by hydrophilic interaction ultra-high-performance liquid chromatography coupled with triple-quadrupole mass spectrometry

Unraveling the Mechanism of Xiaochaihu Granules in Alleviating Yeast-Induced Fever Based on Network Analysis and Experimental Validation

Xiaochaihu granules (XCHG) are extensively used to treat fever. Nevertheless, the underlying mechanism remains elusive. This study aimed to explore the potential of XCHG in mitigating yeast-induced fever and the underlying metabolic pathways. The chemical composition of XCHG was ascertained using ultra-fast liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS), followed by integrated network analysis to predict potential targets. We then conducted experimental validation using pharmacological assays and metabolomics analysis in a yeast-induced mouse fever model. The study identified 133 compounds in XCHG, resulting in the development of a comprehensive network of herb-compound-biological functional modules. Subsequently, molecular dynamic (MD) simulations confirmed the stability of the complexes, including γ-aminobutyric acid B receptor 2 (GABBR2)-saikosaponin C, prostaglandin endoperoxide synthases (PTGS2)-lobetyolin, and NF-κB inhibitor IκBα (NFKBIA)-glycyrrhizic acid. Animal experiments demonstrated that XCHG reduced yeast-induced elevation in NFKBIA's downstream regulators [interleukin (IL)-1β and IL-8], inhibited PTGS2 activity, and consequently decreased prostaglandin E2 (PGE2) levels. XCHG also downregulated the levels of 5-hydroxytryptamine (5-HT), γ-aminobutyric acid (GABA), corticotropin releasing hormone (CRH), and adrenocorticotrophin (ACTH). These corroborated the network analysis results indicating XCHG's effectiveness against fever in targeting NFKBIA, PTGS2, and GABBR2. The hypothalamus metabolomics analysis identified 14 distinct metabolites as potential antipyretic biomarkers of XCHG. In conclusion, our findings suggest that XCHG alleviates yeast-induced fever by regulating inflammation/immune responses, neuromodulation, and metabolism modules, providing a scientific basis for the anti-inflammatory and antipyretic properties of XCHG.

Asparagine-Glucose Amadori Compounds: Formation, Characterization, and Analysis in Dry Jujube Fruit

Amadori rearrangement products of asparagine with glucose (Asn-Glc-ARP) were first prepared through Maillard model reactions and identified via liquid chromatography-mass spectroscopy. With the study on the effect of the reaction temperature, pH values, and reaction time, the ideal reaction condition for accumulation of Asn-Glc-ARP was determined at 100 °C for 40 min under pH 7. Asparagine (Asn) was prone to degrade from Asn-Glc-ARP in alkaline pH values within a lower temperature range, while in an acidic environment with high temperatures, deamidation of Asn-Glc-ARP to Asp-Glc-ARP (Amadori rearrangement products of aspartic acid with glucose) was displayed as the dominant pathway. The deamidation reaction on the side chain of the amide group took place at Asn-Glc-ARP and transferred it into the hydroxyl group, forming Asp-Glc-ARP at the end. Considering that lyophilization as pretreatment led to limited water activity, a single aspartic acid was not deamidated from Asn directly nor did it degrade from Asp-Glc-ARP even at 120 °C. The degradation of Asn-Glc-ARP through tandem mass spectrometry (MS/MS) analysis showed the obvious fragment ion at m/z 211, indicating that the stable oxonium ion formed during fragmentation. The structure of Asn-Glc-ARP was proposed as 1-deoxy-1-l-asparagino-d-fructose after separation and purification. Also, the content of Asn-Glc-ARP within dry jujube fruit (HeTianYuZao) was quantitated as high as 8.1 ± 0.5 mg/g.

Development and comparison of parallel reaction monitoring and data-independent acquisition methods for quantitative analysis of hydrophilic compounds in white tea

In the present work, parallel reaction monitoring (PRM) and data-independent acquisition (DIA) methods were developed for the accurate quantitation of amino acids, alkaloids nucleosides and nucleotides in tea. The quality peaks were significantly enhanced by optimizing the LC elution procedure, HCD voltage, MS resolution, and scanning event. Both methods were validated with good liner linearity (0.004-200 μg/mL), LODs (0.001-0.309 μg/mL for PRM and 0.001-0.564 μg/mL for DIA). Applied to white tea sample, the contents of these hydrophilic compounds were range from 34,655.39 to 70,586.14 mg/kg, and caffeine (32,529.02 mg/kg) and theanine (5483.46 mg/kg) were determined as the most abundant ones. Based on the quantitation data set, the white tea samples from Puer, Lincang and Xishuangbanna were clearly discriminated using multivariate data analysis. The results of the present works show that PRM and DIA have great potential in quantitative analysis of multiple hydrophilic compounds in food samples.

Development and Validation of a Method for Hydrolysis and Analysis of Amino Acids in Ruminant Feeds, Tissue, and Milk Using Isotope Dilution Z-HILIC Coupled with Electrospray Ionization Triple Quadrupole LC-MS/MS

Current analytical methods for amino acid (AA) analysis in ruminant nutrition are time-consuming and expensive. This study aimed to develop a method for AA analysis that is faster, more efficient, rugged, and accessible. Four representative matrixes were selected for method development and validation: milk, tissue, feed, and soy flour standard reference material from National Institute of Standards and Technology. Acid and alkaline hydrolysis were used to analyze 18 AA. Separation of AA was performed using a Z-HILIC column in an 18-min run coupled to a triple quadrupole LC/MS system in positive and negative electrospray ionization for identification and quantitation. The method was evaluated for recovery, precision, calibration curve linearity, and limits of detection (LODs) and limits of quantitation (LOQs) and applied to other feed samples. Good quantitation results were achieved for all AA, with coefficients of determination (R2) over 0.995; LODs at 0.2-28.2 and LOQs at 0.7-94.1 ng/mL; intraday and interday precision <14.9% relative standard deviation; blank recovery between 75.6 and 116.2%; and sample recovery between 75.6 and 118.0%. Overall, AA concentrations were similar to literature values, and there was a tendency for higher N recovery as AA. In conclusion, an efficient and robust method was validated to routinely analyze AA for appropriate characterization in diet formulation for dairy cattle.

Glutamate dehydrogenase in "Liverworld"-A study in selected species to explore a key enzyme of plant primary metabolism in Marchantiophyta

In plants, glutamate dehydrogenase (GDH) is an ubiquitous enzyme that catalyzes the reversible amination of 2-oxoglutarate in glutamate. It contributes to both the amino acid homeostasis and the management of intracellular ammonium, and it is regarded as a key player at the junction of carbon and nitrogen assimilation pathways. To date, information about the GDH of terrestrial plants refers to a very few species only. We focused on selected species belonging to the division Marchantiophyta, providing the first panoramic overview of biochemical and functional features of GDH in liverworts. Native electrophoretic analyses showed an isoenzymatic profile less complex than what was reported for Arabidposis thaliana and other angiosperms: the presence of a single isoform corresponding to an α-homohexamer, differently prone to thermal inactivation on a species- and organ-basis, was found. Sequence analysis conducted on amino acid sequences confirmed a high similarity of GDH in modern liverworts with the GDH2 protein of A. thaliana, strengthening the hypothesis that the duplication event that gave origin to GDH1-homolog gene from GDH2 occurred after the evolutionary bifurcation that separated bryophytes and tracheophytes. Experiments conducted on Marchantia polymorpha and Calypogeia fissa grown in vitro and compared to A. thaliana demonstrated through in gel activity detection and monodimensional Western Blot that the aminating activity of GDH resulted in strongly enhanced responses to ammonium excess in liverworts as well, even if at a different extent compared to Arabidopsis and other vascular species. The comparative analysis by bi-dimensional Western Blot suggested that the regulation of the enzyme could be, at least partially, untied from the protein post-translational pattern. Finally, immuno-electron microscopy revealed that the GDH enzyme localizes at the subcellular level in both mitochondria and chloroplasts of parenchyma and is specifically associated to the endomembrane system in liverworts.

Mechanism of growth inhibition mediated by disorder of chlorophyll metabolism in rice (Oryza sativa) under the stress of three polycyclic aromatic hydrocarbons

Photosynthesis mediated by chlorophyll metabolism is the basis for plant growth, and also the important regulatory mechanism of carbon pool in cropland ecosystems. Soil organic pollutants induced growth inhibition in crop plants, herein, we conducted an in-depth investigation on the effects of three representative polycyclic aromatic hydrocarbons (PAHs), including phenanthrene (PHE), pyrene (PYR), and benzo[a]pyrene (BaP) on rice (Oryza sativa) growth and photosynthesis. PAHs were absorbed via root uptake and accumulated in leaves, causing the swelling of thylakoids and the increase of osmiophilic granules in chloroplasts. The actual quantum efficiency of PSII was significantly decreased under the stress of PHE, PYR, and BaP by 29.9%, 11.9%, and 24.1% respectively, indicating the inhibition in photon absorption and transfer, which was consistent with the decrease of chlorophyll a (22.3%-32.2% compared to the control) in rice leaves. Twenty-two encoding genes involved in chlorophyll metabolism were determined and the results indicated that the expression of chlorophyll synthetases was downregulated by over 50% whereas the degradation process was promoted. Consequently, the production of carbohydrates and the carbon fixation were inhibited, which revealed by the downregulation of intermediate metabolites in Calvin cycle and the declined carboxylation rate. The disturbed photosynthesis resulted in the decrease of the biomasses of both roots (21.0%-42.7%) and leaves (6.4%-22.1%) under the tested PAH stresses. The findings of this study implied that the photosynthetic inhibition was possibly attributed to the disorder of chlorophyll metabolism, thus providing novel insights into the mechanism of growth inhibition induced by organic pollutants and theoretical basis for the estimation of cropland carbon sequestration potential.

Properties investigations of rape stalks fermented by different salt concentration: Effect of volatile compounds and physicochemical indexes

In order to find out the effect of salt concentration on fermented rape stalks, the physicochemical quality and volatile components was investigated using high performance liquid chromatography (HPLC) and headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that there were abundant kinds of free amino acids (FAAs) in all samples, mainly presenting sweet, umami and bitter taste. Through taste activity value (TAV), His, Glu, and Ala contributed significantly to the taste of the sample. 51 volatile components were identified, of which the relative contents of ketones and alcohols were high. By the relative odor activity value (ROAV) analysis, the main components that had a great impact on the flavor were phenylacetaldehyde, β-Ionone, ethyl palmitate and furanone. Adjusting the appropriate salt concentration for fermentation could improve the comprehensive quality of fermented rape stalks and promote the development and utilization of rape products.

HPLC-Parallel accelerator and molecular mass spectrometry analysis of 14C-labeled amino acids

Accelerator mass spectrometry (AMS) is the method of choice for quantitation of low amounts of 14C-labeled biomolecules. Despite exquisite sensitivity, an important limitation of AMS is its inability to provide structural information about the analyte. This limitation is not critical when the labeled compounds are well-characterized prior to AMS analysis. However, analyte identity is important in other experiments where, for example, a compound is metabolized and the structures of its metabolites are not known. We previously described a moving wire interface that enables direct AMS measurement of liquid sample in the form of discrete drops or HPLC eluent without the need for individual fraction collection, termed liquid sample-AMS (LS-AMS). We now report the coupling of LS-AMS with a molecular mass spectrometer, providing parallel accelerator and molecular mass spectrometry (PAMMS) detection of analytes separated by liquid chromatography. The repeatability of the method was examined by performing repeated injections of 14C-labeled tryptophan, and relative standard deviations of the 14C peak areas were ≤10.57% after applying a normalization factor based on a standard. Five 14C-labeled amino acids were separated and detected to provide simultaneous quantitative AMS and structural MS data, and AMS results were compared with solid sample-AMS (SS-AMS) data using Bland-Altman plots. To demonstrate the utility of the workflow, yeast cells were grown in a medium with 14C-labeled tryptophan. The cell extracts were analyzed by PAMMS, and 14C was detected in tryptophan and its metabolite kynurenine.

Response of buckthorn seedlings to foliar spraying with Kelamyth Fe and algae mixture on vegetative growth traits for cultivar AL-Tafahi

This study was done in the lath house of the Horticulture and Gardening Dept. / College of Agriculture / University of Anbar during the growth season 2021 to study the effect of leaf spraying kelamyth chelated Fe in three levels (0, 50, 100 mg.L-1), with three levels Alga Mix of (0, 1, 1.5 g.L-1) and their interaction on vegetative growth traits and leaf content of minerals for buckthorn seedlings AL-Tafahi cultivar. The results showed that the interaction between chelated kelamitic Fe and F2S2 algae mixture at a concentration (100 mg.L-1 kelamitic Fe + 1.5 g.L-1 algae mixture) had given a significant increase in plant height, number of branches, leaf area, chlorophyll, carbohydrates, Fe and saponins. Successively with values (75. 057cm, 19.183 units.seedling-1, 23.833cm2, 41.537 mg. g-1 fresh weight, 3.800%, 194.000 ppm, 1.545 c.ml-1), compared to control treatments. Keywords: Ziziphus mauritiana, chelated iron, seaweed extract, foliar spraying, Buckthorn.

A liquid chromatography-mass spectrometry untargeted urinary metabonomics combined with quantitative analysis of seven amino acids biomarkers on yaobitong capsule in the intervention of rheumatoid arthritis rats

Yaobitong capsule is a compound preparation of traditional Chinese medicine that has been widely applied in disease treatment. To insight into the therapeutic effects of the yaobitong capsule on rheumatoid arthritis and its mechanisms, a liquid chromatography-mass spectrometry untargeted urine metabolomics method was established and validated, combined with the quantitative analysis of seven potential amino acid biomarkers in rat urine. The results showed that 35 potential biomarkers were found in untargeted metabonomics, which was related to amino acid metabolism, lipid metabolism, energy metabolism, and purine metabolism. Moreover, seven amino acid biomarkers, including proline, methionine, glutamic acid, histidine, lysine, cysteine, and glutamine, were further separated and quantified in multiple-reaction monitoring with a positive ionization mode. Then the linearity, standard curves, accuracy, precision, limit of quantitation, recovery, stability, carryover, and matrix effect of the quantitative method were examined. Finally, the validated method was successfully applied to investigate the urine samples of the control group, adjuvant-induced rheumatoid arthritis model group, yaobitong capsule-treatment group, and positive control group in rats. The contents of seven amino acids in different groups showed significant differences. Consequently, our findings revealed that the yaobitong capsule exerted therapeutic effects on rheumatoid arthritis rats by maintaining amino acid homeostasis.

Active compound analysis of Ziziphus jujuba cv. Jinsixiaozao in different developmental stages using metabolomic and transcriptomic approaches

Jujube (Ziziphus jujuba Mill.) is a popular fruit with health benefits ascribed to its various metabolites. These metabolites determine the flavors and bioactivities of the fruit, as well as their desirability. However, the dynamics of the metabolite composition and the underlying gene expression that modulate the overall flavor and accumulation of active ingredients during fruit development remain largely unknown. Therefore, we conducted an integrated metabolomic and transcriptomic investigation covering various developmental stages in the jujube cultivar Z. jujuba cv. Jinsixiaozao, which is famous for its nutritional and bioactive properties. A total of 407 metabolites were detected by non-targeted metabolomics. Metabolite accumulation during different jujube developmental stages was examined. Most nucleotides and amino acids and their derivatives accumulated during development, with cAMP increasing notably during ripening. Triterpenes gradually accumulated and were maintained at high concentrations during ripening. Many flavonoids were maintained at relatively high levels in early development, but then rapidly decreased later. Transcriptomic and metabolomic analyses revealed that chalcone synthase (CHS), chalcone isomerase (CHI), flavonol synthase (FLS), and dihydroflavonol 4-reductase (DFR) were mainly responsible for regulating the accumulation of flavonoids. Therefore, the extensive downregulation of these genes was probably responsible for the decreases in flavonoid content during fruit ripening. This study provide an overview of changes of active components in 'Jinsixiaozao' during development and ripening. These findings enhance our understanding of flavor formation and will facilitate jujube breeding for improving both nutrition and function.

Quantitative analysis of nutrients for nucleosides, nucleobases and amino acids hidden behind five distinct regions-derived Poria cocos using ultra-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry

Poria cocos is an edible fungus used as a health product and traditional Chinese medicinal preparation. Nevertheless, little is known about its nutrients. In this study, ultra-high performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry was conducted to quantify nucleosides, nucleobases, and amino acids in 32 batches of Poria cocos samples collected from Anhui, Sichuan, Hubei, Hunan and Guizhou. Subsequently, the linearity, precision, repeatability, stability, and recovery of our methods were validated. Samples from different regions were clearly separated by partial least squares discriminant analysis and cluster analysis. Our results suggested that Poria cocos samples from different geographical environments differed in nucleosides, nucleobases, and amino acids. The plot of variable importance for projection disclosed differential compositions of L-Leucine, Uridine, L-Asparagine, L-Glutamine, L-phenylalanine, L-Ornithine monohydrochloride, L-Hydroxyproline, Taurine and Inosine in Poria cocos from five regions. We found the highest content of total analytes, total amino acids and total non-essential amino acids in Poria cocos from Anhui, total essential amino acids in the Sichuan samples and total nucleosides in Hunan samples. Overall, we determined the content of Poria cocos-derived nucleosides, nucleobases, and amino acids, providing the foothold for further chemical mining and use of Poria cocos. This article is protected by copyright. All rights reserved.

Rendered-Protein Hydrolysates as a Low-Cost Nitrogen Source for the Fungal Biotransformation of 5-Hydroxymethylfurfural

5-hydroxymethylfurfural (HMF) is a platform chemical that can be converted into a wide range of high-value derivatives. Industrially, HMF-based derivatives are synthesized via chemical catalysis. However, biocatalytic transformation has emerged as an attractive alternative. Significant advances have been made in the last years using isolated enzymes and whole-cell biocatalysts in HMF biotransformation. Nonetheless, one of the major bottlenecks is the cost of the process, mainly due to the microorganism growth substrate. In this work, biotransformation studies to transform HMF into 2,5-di(hydroxymethyl)furan (DHMF) were carried out with the fungus Fusarium striatum using low-cost protein hydrolysates. The protein hydrolysates were obtained from fines, an unexploited material produced during the rendering process of meat industry waste residues. Given the high content in the protein of fines, of around 46%, protein hydrolysis was optimized using two commercially available proteases, Alcalase 2.4 L and Neutrase 0.8 L. The maximum degree of hydrolysis (DH) achieved with Alcalase 2.4 L was 21.4% under optimal conditions of 5% E/S ratio, pH 8, 55 °C, and 24 h. On the other hand, Neutrase 0.8 L exhibited lower efficiency, and therefore, lower protein recovery. After optimization of the Neutrase 0.8 L process using the response surface methodology (RSM), the maximum DH achieved was 7.2% with the variables set at 15% E/S ratio, initial pH 8, 40 °C, and 10.5 h. Using these hydrolysates as a nitrogen source allowed higher sporulation of the fungus and, therefore, the use of a lower volume of inoculum (three-fold), obtaining a DHMF yield > 90%, 50% higher than the yield obtained when using commercial peptones. The presented process allows the transformation of animal co- and by-products into low-cost nitrogen sources, which greatly impacts the industrial feasibility of HMF biotransformation.

Elucidation of the Reinforcing Spleen Effect of Jujube Fruits Based on Metabolomics and Intestinal Flora Analysis

Jujube (Ziziphus jujuba Mill.) fruit (JF) is widely consumed as food in Asian countries due to its potential effects for human health. As a traditional Chinese medicine, JF is often used to treat anorexia, fatigue and loose stools caused by spleen deficiency syndromes in China, but the mechanism underlying this effect has not been thoroughly elucidated. In this study, a rat model of spleen deficiency syndromes was adopted to investigate the therapeutic effect of JF extract and its possible mechanism by metabolomics analyses of plasma and urine as well as the intestinal flora analysis. The results showed that the changes in plasma and urine metabolites caused by spleen deficiency were reversed after administration of JF, and these changed endogenous metabolites were mainly involved in retinol metabolism, pentose and glucuronate interconversions, nicotinate and niacinamide metabolism pathways. The 16S rDNA sequencing results showed that JF could regulate intestinal flora imbalance caused by spleen deficiency. The covariance analysis of intestinal flora structure and metabolome indicated that Aerococcus may be a candidate strain for predicting and treating the metabolic pathways of spleen deficiency and related disorders. In summary, it can be revealed that spleen deficiency, which alters metabolic profiles and the intestinal flora, could be alleviated effectively by JF extract.

Development and validation of an efficient HILIC-QQQ-MS/MS method for quantitative and comparative profiling of 45 hydrophilic compounds in four types of tea (Camellia sentences)

Hydrophilic constituents are significant for the taste and nutrition of tea, but their simultaneous quantification remains challenging due to the lack of efficient methods. Based on the hydrophilic interaction chromatography coupled with triple quadrupole-tandem mass spectrometry, this work developed and validated an efficient (8.5 min per run), sensitive (LOQ: 0.002-0.493 μg/mL) and accurate method. This method was successfully used to determine the contents of 45 hydrophilic constituents in Yunnan large-leaf tea. Umami amino acids and umami-enhanced nucleotides generally exhibited higher content in green tea and Pu-erh raw tea. By contrast, a few number of amino acids (e.g., proline and γ-aminobutyric acid) and most alkaloids and nucleosides showed significantly higher contents in black tea or Pu-erh ripen tea. By performing the orthogonal partial least squares discriminant analysis, classification models for distinguishing four types of tea, and green tea from Pu-erh raw tea were established.

Rumen Fermentation of Feed Mixtures Supplemented with Clay Minerals in a Semicontinuous In Vitro System

Interest in using clays in the diets of ruminants to improve health and performance is increasing. The microbial fermentation of 65:35 (HC) or 35:65 (HF) concentrate:forage feeds, alone or with zeolite (Z), bentonite (B), or sepiolite (S), was studied in an in vitro semicontinuous culture system. The medium pH was allowed to drop for the first 6 h and was gradually buffered thereafter. For the HC diet, the medium pH was higher with Z throughout incubation (p < 0.05). Similar results were observed for the HF diet, but with lower differences between the additives. Throughout incubation, the volume of gas produced was higher with HC than HF (p < 0.05). The gas volume with S was the lowest (p < 0.05) for HC, whereas for HF it was lowest with B from 8 h onwards (p < 0.05). No treatment differences (p > 0.05) were observed in dry matter disappearance, microbial mass, or volatile fatty acids. However, the inclusion of B in HC reduced the ammonia concentration at 6 and 12 h with respect to C (p < 0.05). The inclusion of zeolite as an additive in the diets of ruminants stabilizes the rumen environment during the first stages of fermentation in terms of pH and ammonia concentration, especially in high-concentrate diets. The buffering effect of bentonite and sepiolite was lower, and both might reduce ruminal microbial fermentation, depending on the concentrate proportion.

Determination of 35 Free Amino Acids in Tea Using Ultra-Performance Liquid Chromatography Coupled With Quadrupole Time-of-Flight Mass Spectrometry

The purpose of this research was to develop a simple, sensitive, and accurate method for simultaneous determination of 35 free amino acids using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Tea samples were extracted with boiling water bath, and then separated by XBridge BEH Amide column by gradient elution. The exact mass and MS/MS spectra of the target compound was detected under the TOF–MS and Information dependent acquisition (IDA)–MS/MS mode. The results demonstrated good linearity (R² > 0.9980) in the range of 0.5–1,000 ng/mL. The limits of detection (LODs) were 0.13–25.00 mg/kg and the limits of quantitation (LOQs) were 0.25–50.00 mg/kg. The recovery rate ranged from 70.1 to 105.1% with relative standard deviations (RSDs) <11% (n = 6). This research provides a targeted strategy for developing an analysis method for amino acids in tea.

A merged method for targeted analysis of amino acids and derivatives using parallel reaction monitoring combined with untargeted profiling by HILIC-Q-Orbitrap HRMS

With continuously increased scan rate and sensitivity, high resolution mass spectrometry (HRMS) allows for both reliable targeted analysis (e.g., parallel reaction monitoring, PRM) and a global overview for discovery-based untargeted profiling (e.g., data dependent acquisition, DDA) to be performed. Based on previous study on PRM for large scale targeted metabolomics quantification, we developed an innovative method merged targeted and untargeted approaches in a single run. In our workflow, the scheduled PRM for targeted analysis of amino acids and derivatives combined with the full scan was acquired in every sample injection by hydrophilic interaction liquid chromatography tandem quadrupole-Orbitrap high resolution mass spectrometry (HILIC-Q-Orbitrap HRMS). The identification of metabolic features from full scan was further performed with DDA methodology on grouped quality control (QC) samples and matched with available database. Specifically, 20 amino acids and 40 derivatives were selected for targeted analysis with optimal chromatographic separation and PRM parameters. All isomers within the selected metabolites were totally separated in the robust HILIC condition. 36 of selected metabolites were well-detected and showed a good linearity and reproducibility in NIST SRM 1950 plasma. Moreover, the absolute quantification performance of targeted PRM method was systematically validated using 10 amino acids with the corresponding stable isotope-labeled internal standards (SIL-IS). Finally, the newly developed method was successfully applied to analysis of the plasma samples from patients of pancreatic benign tumor and pancreatic cancer. The significant reduction of circulating amino acids in patients with pancreatic malignancy was confirmed by targeted PRM method and other amino acids modifications as well as polar metabolites were identified with untargeted profiling. Therefore, we have established a workflow that combines specifically and reliably targeted PRM method as well as broad-coverage untargeted profiling, which provides an innovative strategy for basic and clinical metabolomics study.

Evolution of viscera and muscle fractional protein synthesis rate in lean meat selected hybrids and castrated Duroc pigs fed under moderate crude protein restriction

Differences in producing performance and organoleptic meat characteristics among pig genotypes and/or producing types are widely known. These parameters are also subjected to the animal's development, feeding and management. Detailed knowledge of the effects of production phase (PP), pig producing type (PT), dietary protein availability and their interactions on nutrient digestibility, nitrogen balance and protein metabolism is essential information to improve precision feeding techniques. The experiment was a 2 (PP) × 2 (PT) × 2 (diet) factorial design conducted with 32 male pigs, 16 entire F2 pigs progeny of Pietrain sires and Duroc × Landrace dams, and 16 castrated purebred Durocs belonging to two production phases (growing: 29.5 ± 3.19 v. fattening: 88.6 ± 6.26 kg BW), and assigned to one of two dietary CP levels, either standard (SP: 17% in growing and 15% in fattening) or low (LP: 15% in growing and 13% in fattening). Viscera and muscle fractional protein synthesis rates (FSRs; %/day) were conducted through a single infusion of 15% L-[ring-²H₅]-phenylalanine, with subsequent blood sampling from 12 to 40 min, and sample collection of liver, duodenum, biceps femoris and longissimus dorsi skeletal muscles after sacrifice. Fattening animals acquired a greater feed ingestion capacity, average daily gain (P < 0.01) and apparent ileal digestibility, whereas growing pigs showed higher FSRs in both viscera (duodenum and liver) and in longissimus dorsi. F2 pigs showed higher average daily gain, nitrogen retention rates and FSR in liver and longissimus dorsi (P < 0.01). Nevertheless, apparent ileal digestibility in all essential amino acids was lower in F2 compared with Duroc pigs (P < 0.05). Protein metabolism was barely influenced by dietary CP content, although animals fed LP registered the lowest apparent ileal digestibility for CP and also for most of the essential amino acids compared with SP-fed pigs. This information may reveal differences in amino acid requirements between both PTs, with Duroc pigs receiving excess of dietary amino acids.

Impurity profiling of Compound Amino Acid Injection (6AA) using ion-pair high performance liquid chromatography coupled with corona-charged aerosol detection and high resolution mass spectrometry

The complex industrial production process of amino acids (AAs) leads to the existence of a certain amount of impurities in Compound Amino Acid Injection (6AA). It is difficult to obtain its comprehensive and systematic impurity profile using conventional ultraviolet (UV) detectors due to lack of a suitable chromophore in the structures of AAs and their impurities. In our study, a universal ion-pair high performance liquid chromatography (HPLC) method combined with high resolution mass spectrometer (HRMS) and charged aerosol detection (CAD) was developed to identify and determine the content of impurities in Compound Amino Acid Injection (6AA), respectively. After optimizing the content of trifluoroacetic acid (TFA) and heptafluorobutyric acid (HFBA) in the mobile phase on a C18 AQ column, HPLC-CAD method was developed and nine unknown impurities were detected. These impurities were successfully identified using HPLC coupled with orbitrap mass spectrometry and confirmed with their reference substances. The CAD parameters setting was optimized to improve the sensitivity and linearity of the methods before the developed method was validated. The results of validation reflected that the limit of detection (LOD) was approximately 2 ng (corresponding to approximately 0.02 % of L-isoleucine in injection). Under the optimized power function value (PFV) of CAD, the linear range of each impurity was 1 ∼ 200 μg mL^-1 (the linear range of one of the impurities with higher content was 2 ∼ 400 μg mL^-1) with coefficients of determination (R²) greater than 0.998. The recovery rates for nine impurities were 93.37 % ∼ 110.23 %. This study made full use of the qualitative functions of HRMS and the versatility of CAD, revealing possible impurities in the 6AA injection, which could provide reference for the safety research of it.

Determination of seventeen free amino acids in human urine and plasma samples using quadruple isotope dilution mass spectrometry combined with hydrophilic interaction liquid chromatography - Tandem mass spectrometry

Taking into account the growing demand for new analytical procedures that are appropriate for analysis of complex biological samples with increased sensitivity, accuracy and precision, a novel analytical method was described for the determination of underivatized amino acids in human plasma and urine samples. The presented analytical procedure involved the direct analysis of urine samples and the analysis of plasma samples followed by a simple protein precipitation protocol. Samples were analyzed using a simple and fast chromatographic method developed for the determination of 17 different amino acids by liquid chromatography - tandem mass spectrometry. The limit of detection and quantification values for amino acids were ranged between 0.03-2.26 µmol kg^-1 and 0.09-7.54 µmol kg^-1. Matrix effects of plasma and urine on the quantification of analytes were determined by spiking experiments. The accuracy of method was evaluated by matrix matching and quadruple isotope dilution strategies. Excellent accuracy and precision were obtained with the use isotope labeled amino acids demonstrating the high reliability and reproducibility of the proposed method. The percent recovery values were found to be between 98.70 - 101.68% with%RSD below than 1.62% for human plasma and 99.14 - 101.78% with%RSD below than 2.44% for urine samples.

Nutritional components characterization of Goji berries from different regions in China

Goji berries are used as functional food for hundreds of years in Asia, Europe, North America and Austria, and are popular for nutritive properties in global. Commercial Goji berries are mainly produced in Ningxia, Xinjiang, Gansu, Qinghai and Inner Mongolia of China. However, the Goji berries produced in these regions exhibited different appearance and taste. Thus, characterization of the nutritional components in Goji berries produced in these regions could provide the guidance for application of them. In this study, 94 samples were collected, and a total of 20 amino acids, 17 nucleosides and nucleobases, 4 sugars and protein were determined by UHPLC-MS/MS, HPLC-ELSD or UV, and the variation was illustrated through heatmap clustering analysis, PCA and PLS-DA. The results showed that Goji berries from Xinjiang were rich in protein than the samples from other regions; those from Gansu and Ningxia were rich in amino acids, nucleosides and nucleobases; and those from Jiuquan of Gansu and Qinghai were rich in sugars. Heatmap clustering and PCA analysis results showed that all the samples exhibited a significant spatial aggregation, and the producing regions located along the Yellow River (belonging to the Hetao plain) produced Goji berries with the similar chemical profile. Additionally, PLS-DA analysis results showed that fructose and glucose were the predominant markers to distinguish Goji berries from different producing regions.

Free amino acids in African indigenous vegetables: Analysis with improved hydrophilic interaction ultra-high performance liquid chromatography tandem mass spectrometry and interactive machine learning

A hydrophilic interaction (HILIC) ultra-high performance liquid chromatography (UHPLC) with triple quadrupole tandem mass spectrometry (MS/MS) method was developed and validated for the quantification of 21 free amino acids (AAs). Compared to published reports, our method renders collectively improved sensitivity with lower limit of quantification (LLOQ) at 0.5~42.19 ng/mL with 0.3 μL injection volume (or equivalently 0.15~12.6 pg injected on column), robust linear range from LLOQ up to 3521~5720 ng/mL (or 1056 ~ 1716 pg on column) and a high throughput with total time of 6 min per sample, as well as easier experimental setup, less maintenance and higher adaptation flexibility. Ammonium formate in the mobile phase, though commonly used in HILIC, was found unnecessary in our experimental setup, and its removal from mobile phase was key for significant improvement in sensitivity (4~74 times higher than with 5 mM ammonium formate). Addition of 10 (or up to100 mM) hydrochloric acid (HCl) in the sample diluent was crucial to keep response linearity for basic amino acids of histidine, lysine and arginine. Different HCl concentration (10~100 mM) in sample diluent also excreted an effect on detection sensitivity, and it is of importance to keep the final prepared sample and calibrators in the same HCl level. Leucine and isoleucine were distinguished using different transitions. Validated at seven concentration levels, accuracy was bound within 75~125%, matrix effect generally within 90~110%, and precision error mostly below 2.5%. Using this newly developed method, the free amino acids were then quantified in a total of 544 African indigenous vegetables (AIVs) samples from African nightshades (AN), Ethiopian mustards (EM), amaranths (AM) and spider plants (SP), comprising a total of 8 identified species and 43 accessions, cultivated and harvested in USA, Kenya and Tanzania over several years, 2013~2018. The AN, EM, AM and SP were distinguished based on free AAs profile using machine learning methods (ML) including principle component analysis, discriminant analysis, naïve Bayes, elastic net-regularized logistic regression, random forest and support vector machine, with prediction accuracy achieved at ca. 83~97% on the test set (train/test ratio at 7/3). An interactive ML platform was constructed using R Shiny at https://boyuan.shinyapps.io/AIV_Classifier/ for modeling train-test simulation and category prediction of unknown AIV sample(s). This new method presents a robust and rapid approach to quantifying free amino acids in plants for use in evaluating plants, biofortification, botanical authentication, safety, adulteration and with applications to nutrition, health and food product development.

A Review of Edible Jujube, the Ziziphus jujuba Fruit: A Heath Food Supplement for Anemia Prevalence

The fruits of Ziziphus jujuba, commonly known as jujube, red date or Chinese date, are taken as fresh or dried food, and as traditional medicine worldwide due to high nutritional and health values. Traditionally in China, jujube is considered as a medicinal fruit that is being used in treating blood deficiency. In this review, the beneficial effects of jujubes on the hematopoietic functions are summarized and discussed. As illustrated in cell and animal models, the application of jujube extract possessed beneficial effects, including regulation of erythropoiesis via activation of hypoxia inducible factor-induced erythropoietin, potential capacity in recycling heme iron during erythrophagocytosis and bi-directional regulation of immune response. Thus, the blood-nourishing function of jujube is being proposed here. Flavonoid, polysaccharide and triterpenoid within jujube could serve as the potential active ingredients accounting for the aforementioned health benefits. Taken together, these findings provide several lines of evidence for further development of jujube as supplementary products for prevention and/or treatment of anemia.

Evaluation of craft beers through the direct determination of amino acids by capillary electrophoresis and principal component analysis

The composition of beer wort in terms of amino acid (AA) content affects the final product quality, once it is related to the vitality of yeast during the initial exponential growth phase and throughout fermentation. The objective of this work was the use of a capillary zone electrophoresis method with UV-vis detection in association with Principal Component (Data) Analysis for craft beer classification. Cysteine, histidine, phenylalanine, lysine, tryptophan and arginine were the monitored AAs in wort and finished beer, which were extracted through cation exchange resin. Good differentiation among samples according to their production was obtained, showing a profile of AAs (<LQ-99 µg mL^-1) for each wort, which can be used as indicator of the quality of a beer. One of the samples had the mashing step monitored, showing an increasing profile in the concentrations of AAs (6.5-55 µg mL^-1), which can be explained by the protein cleavage.

Changes in free amino acids of fermented minced peppers during natural and inoculated fermentation process based on HPLC-MS/MS

Free amino acids (FAAs) participate in the synthesis of quality characteristic ingredients and taste substances in fermented minced peppers (FMPs), and they can be affected by fermentation method and time. In this study, changes in FAAs of FMP during natural fermentation (NF) and inoculated fermentation (IF) process were characterized by HPLC-MS/MS. The results showed that a total of 20 FAAs were identified, including 8 essential amino acids (AAs), 2 semiessential AAs, and 10 nonessential AAs. Comparing with other FAAs, Gln, Arg, and Asn presented higher content in the whole NF or IF periods. The FAAs content of NF and IF samples showed similar tendency during fermentation process, which first increased and then decreased. The highest content of most FAAs in IF and NF samples was obtained on the 18- and 12-day, respectively. Moreover, the FAA content in IF samples was higher than that in NF ones at the same fermentation time. The taste AAs content accounted for 23.3% to 50.0% in total FAAs, and taste activity value of bitter and umami was higher than sweet and aromatic ones. Based on principal component analysis, comprehensive analysis ranking, and heat map clustering analysis, FMP obtained by IF posed better FAAs quality than NF samples during fermentation process. PRACTICAL APPLICATION: Free amino acids (FAAs) participate in the synthesis of quality characteristic ingredients and taste substances in fermented minced peppers (FMPs), and they can be affected by fermentation method and time. Changes in FAA varieties and level in FMP during natural fermentation (NF) and inoculated fermentation (IF) process were analyzed using HPLC-MS/MS. Then, they were performed by principal component analysis (PCA), and clustered with the heat map. The results showed that FMP obtained by IF posed better FAAs quality than NF samples in the whole fermentation. HPLC-MS/MS was a reliable and effective mean for determining the FAAs and could provide regulation guidelines for improving the quality of FMP during fermentation process.

Fast quantification of free amino acids in food by microfluidic voltage-assisted liquid desorption electrospray ionization-tandem mass spectrometry

A method based on microfluidic voltage-assisted liquid desorption electrospray ionization-tandem mass spectrometry (VAL-DESI-MS/MS) has been developed for fast quantification of free amino acids in food. Food extracts were transferred to the microfluidic platform and analyzed by liquid desorption ESI-MS/MS. Deuterated aspartic acid (i.e., 2,2,3-d3-Asp) was used as internal standard for analysis. The method had linear calibration curves with r2 values > 0.998. Limits of detection were at the level of sub μM for the amino acids tested, i.e., glutamic acid (Glu), arginine (Arg), tyrosine (Tyr), tryptophan (Trp), and phenylalanine (Phe). To validate the proposed method in food analysis, extracts of Cordyceps fungi were analyzed. Amino acid contents were found in the range from 0.63 mg/g (Tyr in Cordyceps sinensis) to 4.44 mg/g (Glu in Cordyceps militaris). Assay repeatability (RSD) was ≤ 5.2% for all the five amino acids measured in all the samples analyzed. Recovery was found in the range from 95.8 to 105.1% at two spiking concentrations of 0.250 mg/g and 1.00 mg/g. These results prove that the proposed microfluidic VAL-DESI-MS/MS method offers a quick and convenient means of quantifying free amino acids with accuracy and repeatability. Therefore, it may have potential in food analysis for nutritional and quality assessment purposes. Graphical abstract.

Analysis of sugars and amino acids in aphid honeydew by hydrophilic interaction liquid chromatography – Mass spectrometry

Past analyses of sugar and amino acid composition of aphid honeydews have been completed using diverse instrumentation. Here we report the use of hydrophilic interaction liquid chromatography (HILIC) coupled with a triple quadrupole mass spectrometric (MS/MS) detector for the analysis of seven saccharides (xylose, fructose, glucose, sucrose, trehalose, melezitose and raffinose) and five amino acids (glutamic acid, glutamine, aspartic acid, serine, and asparagine). Limits of quantitation ranged from 0.05 mg/L (melezitose) to 1.0 mg/L (fructose) for sugars and from 0.10 mg/L (glutamic acid) to 3.66 mg/L (asparagine) for amino acids. Sample preparation was fast and simple, requiring only the washing of foils used to collect aphid honeydew with hot (80 °C) water and sonication of samples prior to HILIC/MS/MS analysis for both classes of analytes. No analyte derivatization was required and excellent chromatographic characteristics were observed. For those studying honeydew-mediated interactions in the field, this technique allows for rapid characterization of ecologically important amino acids and sugars.•

Composition of seven saccharides in Aphis asclepiadis honeydew including xylose, fructose, glucose, sucrose, trehalose, melezitose,and raffinose, and five standard amino acids including glutamic acid, glutamine, aspartic acid, serine, and asparagine, were analyzed using hydrophilic interaction liquid chromatography-mass spectrometry.

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All polar analytes were analyzed without derivatization using HILIC-MS with chromatographic run times of 7 min (sugars) and 10 min (amino acids).

Validation of a HILIC UHPLC-MS/MS Method for Amino Acid Profiling in Triticum Species Wheat Flours

Amino acids are essential nutritional components as they occur in foods either in free form or as protein constituents. An ultra-high-performance (UHPLC) hydrophilic liquid chromatography (HILIC)-tandem Mass Spectrometry (MS) method has been developed and validated for the quantification of 17 amino acids (AA) in wheat flour samples after acid hydrolysis with 6 M HCl in the presence of 4% (v/v) thioglycolic acid as a reducing agent. The developed method proved to be a fast and reliable tool for acquiring information on the AA profile of cereal flours. The method has been applied and tested in 10 flour samples of spelt, emmer, and common wheat flours of organic or conventional cultivation and with different extraction rates (70%, 90%, and 100%). All the aforementioned allowed us to study and evaluate the variation of the AA profile among the studied flours, in relation to other quality characteristics, such as protein content, wet gluten, and gluten index. Significant differences were observed in the AA profiles of the studied flours. Moreover, AA profiles exhibited significant interactions with quality characteristics that proved to be affected based mainly on the type of grain. A statistical and multivariate analysis of the AA profiles and quality characteristics has been performed, as to identify potential interactions between protein content, amino acids, and quality characteristics.

Accurate and efficient amino acid analysis for protein quantification using hydrophilic interaction chromatography coupled tandem mass spectrometry

BACKGROUND

Methods used to quantify protein from biological samples are often inaccurate with significant variability that requires care to minimize. The errors result from losses during protein preparation and purification and false detection of interfering compounds or elements. Amino acid analysis (AAA) involves a series of chromatographic techniques that can be used to measure protein levels, avoiding some difficulties and providing specific compositional information. However, unstable derivatives, that are toxic and can be costly, incomplete reactions, inadequate chromatographic separations, and the lack of a single hydrolysis method with sufficient recovery of all amino acids hinder precise protein quantitation using AAA.

RESULTS

In this study, a hydrophilic interaction chromatography based method was used to separate all proteinogenic amino acids, including isobaric compounds leucine and isoleucine, prior to detection by multiple reaction monitoring with LC-MS/MS. Through inclusion of commercially available isotopically labeled (13C, 15N) amino acids as internal standards we adapted an isotopic dilution strategy for amino acid-based quantification of proteins. Three hydrolysis methods were tested with ubiquitin, bovine serum albumin, (BSA), and a soy protein biological reference material (SRM 3234; NIST) resulting in protein estimates that were 86-103%, 82-94%, and 90-99% accurate for the three protein samples respectively. The methane sulfonic acid hydrolysis approach provided the best recovery of labile amino acids including: cysteine, methionine and tryptophan that are challenging to accurately quantify.

CONCLUSIONS

Accurate determination of protein quantity and amino acid composition in heterogeneous biological samples is non-trivial. Recent advances in chromatographic phases and LC-MS/MS based methods, along with the availability of isotopic standards can minimize difficulties in analysis and improve protein quantitation. A robust method is described for high-throughput protein quantification and amino acid compositional analysis. Since accurate measurement of protein quality and quantity are a requirement for many biological studies that relate to crop improvement or more generally, our understanding of metabolism in living systems, we envision this method will have broad applicability.

A Dual Ligand Sol⁻Gel Organic-Silica Hybrid Monolithic Capillary for In-Tube SPME-MS/MS to Determine Amino Acids in Plasma Samples

This work describes the direct coupling of the in-tube solid-phase microextraction (in-tube SPME) technique to a tandem mass spectrometry system (MS/MS) to determine amino acids (AA) and neurotransmitters (NT) (alanine, serine, isoleucine, leucine, aspartic acid, glutamic acid, lysine, methionine, tyrosine, and tryptophan) in plasma samples from schizophrenic patients. An innovative organic-silica hybrid monolithic capillary with bifunctional groups (amino and cyano) was developed and evaluated as an extraction device for in-tube SPME. The morphological and structural aspects of the monolithic phase were evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nitrogen sorption experiments, X-ray diffraction (XRD) analyses, and adsorption experiments. In-tube SPME-MS/MS conditions were established to remove matrix, enrich analytes (monolithic capillary) and improve the sensitivity of the MS/MS system. The proposed method was linear from 45 to 360 ng mL^-1 for alanine, from 15 to 300 ng mL^-1 for leucine and isoleucine, from 12 to 102 ng mL^-1 for methionine, from 10 to 102 ng mL^-1 for tyrosine, from 9 to 96 ng mL^-1 for tryptophan, from 12 to 210 ng mL^-1 for serine, from 12 to 90 ng mL^-1 for glutamic acid, from 12 to 102 ng mL^-1 for lysine, and from 6 to 36 ng mL^-1 for aspartic acid. The precision of intra-assays and inter-assays presented CV values ranged from 1.6% to 14.0%. The accuracy of intra-assays and inter-assays presented RSE values from -11.0% to 13.8%, with the exception of the lower limit of quantification (LLOQ) values. The in-tube SPME-MS/MS method was successfully applied to determine the target AA and NT in plasma samples from schizophrenic patients.

Comparative Analysis of Carbohydrates, Nucleosides and Amino Acids in Different Parts of Trichosanthes kirilowii Maxim. by (Ultra) High-Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry and Evaporative Light Scattering Detector Methods

Trichosanthes kirilowii Maxim. is one of the original plants for traditional Chinese medicines Trichosanthis Fructus, Trichosanthis Semen, Trichosanthis Pericarpium and Trichosanthis Radix. Amino acids, nucleosides and carbohydrates are usually considered to have nutritional value and health-care efficacy. In this study, methods involving high-performance liquid chromatography coupled with evaporative light scattering detector (HPLC-ELSD), UV-visible spectrophotometry and ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) were established for quantifying carbohydrates (fructose, glucose, stachyose, raffinose and polysaccharide), fourteen nucleosides and twenty one amino acids. Moreover, sixty-three samples from nine different parts, including pericarp, seed, fruit pulp, stem, leaf, main root, main root bark, lateral root and lateral root bark of T. kirilowii from different cultivated varieties were examined. The established methods were validated with good linearity, precision, repeatability, stability, and recovery. The results showed that the average content of total amino acids in roots (15.39 mg/g) and root barks (16.38 mg/g) were relatively higher than for others. Contents of nucleosides in all parts of T. kirilowii were below 1.5 mg/g. For carbohydrates, fruit pulp has a higher content than others for glucose (22.91%), fructose (20.63%) and polysaccharides (27.29%). By using partial least-squared discriminate analysis (PLS-DA), Variable importance in the projection (VIP) plots and analysis of variance (ANOVA) analysis, the characteristic components of the different organs (fruit, stems and leaves, roots) were found. This analysis suggested there were potential medicinal and nutritive health care values in various parts of the T. kirilowii, which provided valuable information for the development and utilization of T. kirilowii.

Mechanisms non-enzymatic browning in orange juice during storage

The role of Reactive Carbonyl Species (RCS) derived from the Maillard reaction and ascorbic acid degradation on brown color formation was investigated in orange juice during storage. Eight RCS were monitored in aseptic juice over an 8-week period under refrigerated (4 °C) and accelerated conditions (35 °C). Significant changes in RCS concentrations were reported and positively correlated with color formation. Recombination experiments demonstrated the significant role of 3-deoxyglucosone and acetol on color formation as well as their interactions with glyoxal and methylglyoxal that lead to an increase in browning. Isotopic enrichment techniques further identified fructose as the main precursor of RCS, indicating the important role of Maillard reaction as a mechanism of non-enzymatic browning during orange juice storage. Finally, among the amino acids, tryptophan and glutamine showed the largest percentage losses in orange juice during storage and were reported to significantly impact the RCS composition and color formation.

Identification of interactions between multiple components in Socheongryong-tang using a plant profiling approach

Traditional herbal medicine consists of multiple components. There are interactions among the components, which affect both potency and toxicity. The preparation of herbal medicines can be a cause of interactions between multicomponents in herbs. To demonstrate the differences in multiherb interactions based on the preparation methods, the changes in the active components in the different preparations of Socheongryong-tang (SCRT) were evaluated using metabolomics profiling. We performed multicomponent profiling of the decoction of SCRT (SCRTD) and individual herb mixture (SCRTM) using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Active compounds from SCRTD and SCRTM were identified using multivariate analysis, and the activities between the two groups were compared. We also evaluated the anti-inflammatory effect of SCRT through investigating the protein expression of iNOS and COX-2 in lipopolysaccharide-induced macrophage RAW 264.7 cells in both groups. From the multivariate analysis, 53 active compounds that have different intensities between SCRTD and SCRTM were identified. The intensities of those components, such as ephedrines, glycyrrhizic acid, 6-gingerol and (2E,4E,8Z,10E)-N-isobutyl-2,4,8,10-dodecatetraenamide, which is newly identified in Asiasarum heterotropoides, were mostly higher in SCRTD than in SCRTM, which was related to the anti-inflammatory effect. From the iNOS inhibition test, it was found that SCRTD had a stronger anti-inflammatory effect than SCRTM. It was demonstrated that multicomponent interactions can be changed by the preparation method, and finally the anti-inflammatory effect in SCRT can be affected.

Amino acids and biogenic amines as food quality factors

The importance of amino acids and biogenic amines is widely recognised in various fields, particularly in the fields of food science and nutrition. This mini-review contains a summary of my main research field that centres on aspects of Food Quality and Food Safety, with a particular emphasis on amino acids and biogenic amines. It also gives an overview of the recent developments on the related areas.

A combined targeted/untargeted LC-MS/MS-based screening approach for mammalian cell lines treated with ionic liquids: Toxicity correlates with metabolic profile

This work presents the development and validation of a quantitative HILIC UHPLC-ESI-QTOF-MS/MS method for amino acids combined with untargeted metabolic profiling of human corneal epithelial (HCE) cells after treatment with ionic liquids. The work included a preliminary metabotoxicity screening of 14 different ionic liquids, of which 9 carefully selected ionic liquids were chosen for a metabolomics study. This study is focused on the correlation between the toxicity of the ionic liquids and their metabolic profiles. The method development included the comparison of different MS/MS acquisition modes. A sequential window acquisition of all theoretical fragment ion mass spectra (SWATH) method with variable Q1 window widths and narrow Q1 target windows of 5 Da for most of the amino acids was selected as the optimal acquisition mode. Due to the absence of a true blank matrix, ¹³C,¹⁵N-isotopically labelled amino acids were utilized as surrogate calibrants, instead of proteinogenic amino acids. Partial least squares (PLS) analysis of the median effective concentrations (EC₅₀) of 9 selected ionic liquids showed a correlation with their metabolic profile measured by the untargeted screening.

Development and validation of a hydrophilic interaction ultra-high-performance liquid chromatography-tandem mass spectrometry method for rapid simultaneous determination of 19 free amino acids in rat plasma and urine

Determination of amino acids in biofluids is a challenging task because of difficulties deriving from their high polarity and matrix interference. A simple, reliable and high-throughput hydrophilic interaction UHPLC-MS/MS method was developed and validated for the rapid simultaneous determination of 19 free amino acids in rat plasma and urine samples in this paper. Hydrophilic method with a Waters Acquity UPLC BEH Amide column (100 × 2.1 mm,1.7 μm) was used with a gradient mobile phase system of acetonitrile and water both containing 0.2% formic acid. The analysis was performed on a positive electrospray ionization mass spectrometer via multiple reaction monitoring. Samples of 10 μL plasma and 50 μL urine were spiked with three deuterated internal standards, pretreated with 250 μL acetonitrile for one-step protein precipitation and a final dilution of urine samples. Good linearities (r > 0.99) were obtained for all of the analytes with the lower limit of quantification from 0.1 to 1.2 μg/mL. The relative standard deviation of the intra-day and inter-day precisions were within 15.0% and the accuracy ranged from -12.8 to 12.7%. The hydrophilic interaction UHPLC-MS/MS method was rapid, accurate and high-throughput and exhibited better chromatography behaviors than the regular RPLC methods. It was further successfully applied to detect 19 free amino acids in biological matrix.

Arginine reprogramming in ADPKD results in arginine-dependent cystogenesis

Research into metabolic reprogramming in cancer has become commonplace, yet this area of research has only recently come of age in nephrology. In light of the parallels between cancer and autosomal dominant polycystic kidney disease (ADPKD), the latter is currently being studied as a metabolic disease. In clear cell renal cell carcinoma (RCC), which is now considered a metabolic disease, we and others have shown derangements in the enzyme arginosuccinate synthase 1 (ASS1), resulting in RCC cells becoming auxotrophic for arginine and leading to a new therapeutic paradigm involving reducing extracellular arginine. Based on our earlier finding that glutamine pathways are reprogrammed in ARPKD, and given the connection between arginine and glutamine synthetic pathways via citrulline, we investigated the possibility of arginine reprogramming in ADPKD. We now show that, in a remarkable parallel to RCC, ASS1 expression is reduced in murine and human ADPKD, and arginine depletion results in a dose-dependent compensatory increase in ASS1 levels as well as decreased cystogenesis in vitro and ex vivo with minimal toxicity to normal cells. Nontargeted metabolomics analysis of mouse kidney cell lines grown in arginine-deficient versus arginine-replete media suggests arginine-dependent alterations in the glutamine and proline pathways. Thus, depletion of this conditionally essential amino acid by dietary or pharmacological means, such as with arginine-degrading enzymes, may be a novel treatment for this disease.

Pharmacokinetic Comparisons of Multiple Triterpenic Acids from Jujubae Fructus Extract Following Oral Delivery in Normal and Acute Liver Injury Rats

Jujubae Fructus, the dried fruit of Ziziphus jujuba, has been used as Chinese medicine and food for centuries. Triterpenic acids have been found to be the major bioactive constituents in Jujubae Fructus responsible for their hepatoprotective activity in previous phytochemical and biological studies, while few pharmacokinetic studies have been conducted. To reveal the kinetics of the triterpenic acids under the pathological liver injury state, an established ultra-performance liquid chromatography coupled with a mass spectrometry method was applied for the simultaneous quantitation of seven triterpenic acids (ceanothic acid, epiceanothic acid, pomonic acid, alphitolic acid, maslinic acid, betulinic acid, and betulonic acid) in plasma samples of normal and acute liver injury rats induced by CCl₄. The results showed that there were significant differences (p < 0.05) in the pharmacokinetic parameters of seven triterpenic acids between model and normal groups. The AUC_0–t and AUC_0–∞ of epiceanothic acid (5227 ± 334 μg&sdot;h/L vs. 1478 ± 255 μg ⋅ h/L and 6127 ± 423 μg ⋅ h/L vs. 1482 ± 255 μg ⋅ h/L, respectively) and pomonic acid (4654 ± 349 μg ⋅ h/L vs. 1834 ± 225 μg ⋅ h/L and 4776 ± 322 μg ⋅ h/L vs. 1859 ± 230 μg ⋅ h/L, respectively) in model rats were significantly higher than those in normal rats, and the CLz/F of them were significantly decreased (0.28 ± 0.02 L/h/kg vs. 1.36 ± 0.18 L/h/kg and 19.96 ± 1.30 L/h/kg vs. 53.15 ± 5.60 L/h/kg, respectively). In contrast, the above parameters for alphitolic acid, betulinic acid and betulonic acid exhibited the quite different trend. This pharmacokinetic research might provide useful information for the clinical usage of triterpenic acids from Jujubae Fructus.

Characterization of molecular signature of the roots of Paeonia lactiflora during growth

The roots of Paeoniae lactiflora Pall. are widely consumed as crude drugs in Asian countries due to their remarkable beneficial health effects. The present research was undertaken to illuminate the dynamic changes in metabolites and enzymes and facilitate selection of the harvesting time when the herb can provide optimum health benefits. P. lactiflora roots were analyzed at 12 stages of growth for monoterpenoid glycosides, phenols, nucleosides, nucleobases, amino acids, and polysaccharides by high-performance liquid chromatography with photodiode array detector, ultra-high pressure liquid chromatography coupled with tandem mass spectrometry, and UV spectrophotometry. The enzyme activities of plant β-glucosidases and esterases were determined by UV methods. The total content of monoterpenoid glycosides and phenols peaked in December. For nucleosides and nucleobases, the highest content appeared in April. The maximum phasic accumulation of the total amino acids took place in March, and the content of total polysaccharides reached a peak value in September. December, April, and March were selected as the appropriate harvesting times for producing natural medicinal or health food products. Plant β-glucosidases and esterases showed the highest activity in December and May, respectively. When the activity of β-glucosidase increased, esterase activity decreased, while the contents of oxypaeoniflora and paeoniflorin increased. When esterase activity increased, the contents of benzoylpaeoniflorin, paeoniflorin, and gallic acid decreased. In conclusion, the results from the present study would be useful in determination of the suitable time for harvesting P. lactiflora roots for medicinal purposes.

Hydrophilic interaction chromatography in food matrices analysis: An updated review

This review focuses on the most recent papers (from 2011 to submission date in 2017) dealing with the analysis of different organic components in foods (i.e. nucleobases, nucleosides, nucleotides, uric acid, and creatinine, amino acids and related compounds, choline-related compounds and phospholipids, carbohydrates, artificial sweeteners and polyphenolic compounds), using hydrophilic interaction liquid chromatography (HILIC) combined with different detection techniques. For each compound class, the investigated food matrices are grouped per: foods of animal origin, vegetables, fruits and related products, baby food, and other matrices such as drinks and mushrooms/fungi. Furthermore, the main advantages of HILIC chromatography respect to the other commonly used techniques are discussed.

Comparative pharmacokinetics of triterpenic acids in normal and immunosuppressed rats after oral administration of Jujubae Fructus extract by UPLC-MS/MS

The fruit of Ziziphus jujuba (Jujubae Fructus) has been used as food and crude drug for thousands of years. Although several chemical and biological studies have revealed triterpenic acid as the main bioactive constituent of Jujubae Fructus responsible for immune-regulatory activity, only few pharmacokinetic studies have been conducted. To comprehend the kinetics of triterpenic acids and promote their curative application, a sensitive and efficient ultra-performance liquid chromatography coupled with mass spectrometry method (UPLC-MS/MS) was established. UPLC-MS/MS was applied for the simultaneous determination of ceanothic acid, epiceanothic acid, pomonic acid, alphitolic acid, maslinic acid, betulinic acid, and betulonic acid in normal and immunosuppressed rat plasma samples. After sample preparation, chromatographic separation was performed on an Acquity UPLC BEH C₁₈ column (2.1 × 100 mm, 1.7 μm) with acetonitrile: methanol (1:1, v/v) and 0.5% ammonium acetate in water as mobile phase. The established method was validated and found to be specific, accurate, and precise for the seven triterpenic acids, and was successfully applied for the pharmacokinetic study of rat plasma samples. The results showed that the pharmacokinetic parameters (C_max, T_max, AUC_0-t, AUC_0-∞, and CLz/F) in the plasma samples of immunosuppressed rats were significantly different from those in normal rats, and might provide an insight for the clinical usage of triterpenic acids from Jujubae Fructus.