LC-MS Spectra Research Articles

Two Reaction-Based Fluorescent Sensors with Cationic Group Enable High-Selective Detection of HSO3– in the Environment

Fluorescent PVBTI and HPVBTI with D-π–A structure were synthesized and could sensitively and selectively sense bisulfite (HSO3–) in phosphate-buffered saline solution (pH 7.4) via a Michael-addition mechanism. The introduction of a cationic group in two sensors efficiently avoided the interference of common cations in environmental samples. PVBTI and HPVBTI had high-selectivity to HSO3– over other anions and cations and they could detect HSO3– with the low detection limits of 13.3 nM and 26.7 nM, respectively. Their sensing mechanism was confirmed by 1H NMR and LC–MS spectra. HSO3– was detected by two fluorescent sensors in tap water, lake water, river water, and paddy water with satisfactory results, suggesting that PVBTI and HPVBTI could be as the practical sensing platform for sensitive and selective analysis of HSO3– in the environment.

Synthesis of a Highly Efficient Multifunctional Copper (II)‐Pyridyl Complex for Adsorption and Photocatalytic Degradation of Organic Dyes

AbstractA new copper (II) pyridyl complex CP1, has been synthesized for adsorption as well as photocatalytic degradation of Methylene Blue (MB) and Rhodamine B (RhB) dyes and characterized through FT‐IR, LC–MS, FE‐SEM, TEM and EPR studies. The density functional theoretical (DFT) study was performed to determine the mode of binding of CuII ions with ligand 1 to form complex CP1. Photoluminescence study in solid state suggests that CP1 could act as potential green light emitter. The adsorption of MB and RhB dyes on the surface of CP1 is found to depend on adsorbent dosage, initial concentration of dyes and contact time. In addition, adsorption of dyes on CP1 is found to follow Freundlich adsorption isotherm and pseudo‐second order kinetics. The photocatalytic degradation was performed under visible light irradiation which reveals that 95.8% of MB (16 mgL−1) and 93.7% of RhB (23.95 mgL−1) can be decolorized in 35 minutes using 0.3 gL−1 of catalyst. To determine the intermediates formed during photocatalytic degradation of dyes, LC–MS spectra is also obtained. From the LC–MS spectra, intermediates are identified and mechanism of degradation of dyes has been proposed.

Centrifugal partition chromatography as a fractionation tool for the analysis of lignocellulosic biomass products by liquid chromatography coupled to mass spectrometry

The conversion of lignocellulosic biomass into biofuels and bio-products leads to oxygenated matrices having a wide range of polarities and molecular weights. A complete analytical characterization of these complex mixtures is necessary to improve conversion processes. In this study, an innovative centrifugal partition chromatography (CPC) protocol was developed to fractionate aqueous biomass samples with a MTBE-water solvent system, by mixing elution, displacement and extrusion modes in the same run. This new protocol was validated on model molecules and applied to the water soluble phase of a fast pyrolysis bio-oil. It demonstrated a promising separation with a relevant selectivity on the most significant chemical families of biomass samples: carbohydrates, furans, carboxylic acids and phenols. CPC fractions of the sample were collected and analyzed comprehensively by HPLC-UV/MS (with ESI negative and positive ionization modes). This CPC x LC approach allowed more accurate attributions on the 217 peaks detected. The use of different detection modes gave a complete view of the water soluble phase of a fast pyrolysis bio-oil through 2D maps. Molecular characterization was enhanced by independent information: CPC retention time, LC retention time, UV and MS spectra. Concomitance of these different chemical information is of precious help for unambiguous identification.

Cardioprotective Activity of Some 2-Arylimino-1,3-Thiazole Derivatives

The article presents the synthesis of 2-arylimino-4-methyl-2,3-dihydro-1,3-thiazoles via Hantzsch reaction of thioureas and 3-chloropentane-2,4-dione or ethyl 2-chloro-3-oxobutanoate. The structure of synthesized compounds was confirmed by LCMS, 1H, and 13C NMR spectra. Cardioprotective activity of synthesized thiazole derivatives were studied in vitro on the isolated rings of the thoracic aorta of laboratory rats. Based on pharmacological studies, the tested compounds possessed a moderate to high cardioprotective effect. A prospective 1-[2-(4-methoxyphenylimino)-4-methyl-3-(4-methylpiperazine-1-yl)-2,3-dihydro-1,3-thiazole-5-yl] ethan-1-one hydrochloride 4c was identified. The mentioned compound has delayed the development of constrictor responses of isolated rings of the thoracic rat aorta and exceeds the activity of L-carnitine by 18.2% and meldonium by 12.9%. The compound 4c may be proposed as a potential cardioprotective agent for in-depth pharmacological studies.

Statistically correlating NMR spectra and LC-MS data to facilitate the identification of individual metabolites in metabolomics mixtures

NMR and LC-MS are two powerful techniques for metabolomics studies. In NMR spectra and LC-MS data collected on a series of metabolite mixtures, signals of the same individual metabolite are quantitatively correlated, based on the fact that NMR and LC-MS signals are derived from the same metabolite covary. Deconvoluting NMR spectra and LC-MS data of the mixtures through this kind of statistical correlation, NMR and LC-MS spectra of individual metabolites can be obtained as if the specific metabolite is virtually isolated from the mixture. Integrating NMR and LC-MS spectra, more abundant and orthogonal information on the same compound can significantly facilitate the identification of individual metabolites in the mixture. This strategy was demonstrated by deconvoluting 1D 13C, DEPT, HSQC, TOCSY, and LC-MS spectra acquired on 10 mixtures consisting of 6 typical metabolites with varying concentration. Based on statistical correlation analysis, NMR and LC-MS signals of individual metabolites in the mixtures can be extracted as if their spectra are acquired on the purified metabolite, which notably facilitates structure identification. Statistically correlating NMR spectra and LC-MS data (CoNaM) may represent a novel approach to identification of individual compounds in a mixture. The success of this strategy on the synthetic metabolite mixtures encourages application of the proposed strategy of CoNaM to biological samples (such as serum and cell extracts) in metabolomics studies to facilitate identification of potential biomarkers.

Novel acyl thiourea derivatives: Synthesis, antifungal activity, gene toxicity, drug-like and molecular docking screening.

Nine novel acyl thioureas were synthesized. Their identities and purities were confirmed by LC-MS spectra; each structure was elucidated by elemental analysis, IR, 1 Н and 13 C NMR spectra. Applying an in vitro screening of their antifungal potential, three substances (3, 5, and 6) could be selected as showing high activity against 11 fungi and 3 Phytophthora strains of phytopathogenic significance. Analysis of gene toxicity with the Salmonella reverse mutagenicity test, as an assessment of drug likeness, lipophilicity, and calculations of frontier molecular orbitals assign a low toxicity profile to these compounds. Molecular docking studies point to 14α-demethylase (CYP51) and N-myristoyltransferase (NMT) as possible fungal targets for growth inhibition. The findings are discussed with respect to structure-activity relationship (SAR).

Modulation of hepatic lipidome by rhodioloside in high-fat diet fed apolipoprotein E knockout mice

BackgroundRhodioloside is a glucoside of tyrosol isolated from Rhodiola rosea. However, its regulating effect on hepatic dyslipidemia of atherogenic mice has rarely been studied. PurposeThe specific aims of current study included to clarify lipidomic perturbation in liver tissues of apolipoprotein E deficient (apoE−/−) mice fed with high-fat diet, and to examine the effects of rhodioloside against atherosclerosis and dyslipidemia. Study DesignThe comparisons of hepatic lipidome were executed between wide type (WT) mice fed with normal diet (NDC) and apoE−/− mice fed with high-fat diet (Model), WT mice fed with high-fat diet (HFDC) versus the model mice, as well as the model mice versus rhodioloside-treated atherosclerotic mice. MethodsUltra high performance liquid chromatography coupled with a Q exactive hybrid quadrupole-orbitrap mass spectrometry (UPLC-MS/MS) was employed to provide an unbiased and simultaneous measurement of individual lipid species in liver tissues. ResultsMultivariate statistical analysis derived from LC-MS spectra revealed that high-fat diet and apoE deficiency caused a series of disturbances on glyerolipid metabolism, glycerophospholipid metabolism and sphingolipid metabolism. Rhodioloside administration showed atheroprotective effects on the apoE−/− mice with regulating the levels of 1 phosphatidylcholine, 2 phosphatidylserines, 5 alkyldiacylglycerols and 3 alkenyldiacylglycerols back to normal. In particular, PC (4:0/15:0) was positively associated with high-density lipoprotein cholesterol in blood, both of which could be ameliorated by rhodioloside. ConclusionOur results identified the abnormal hepatic lipids in atherosclerosis progression that could efficiently improved by rhodioloside. These lipids contributed to biological understanding of atherogenic dyslipidemia in liver and could also served as sensitive indicators for drug target screening.

Solid-phase synthesis of peptides containing aminoadipic semialdehyde moiety and their cyclisations

Pathological levels of oxidative stress (OS) have been implicated in many diseases including diabetes mellitus, neurodegenerative diseases, inflammatory diseases, atherosclerosis, and cancer. Studies of oxidative stress are however complicated by the low concentration of oxidation products. To resolve this problem, we tested a new derivative of aminoadipic semialdehyde (Fmoc-Aea-OH) in the solid-phase synthesis of carbonylated peptides. We prepared a series of peptides with free and acetylated N-terminal amino groups using the Fmoc-Aea-OH reagent. LC-MS, ESI-MS, and MS/MS spectra confirmed the sequences of the modified peptides, although the LC-MS and ESI-MS spectra were dominated by signals corresponding to dehydration products. NMR studies of acetylated products revealed that the dominant product formed in this reaction contains a 1,2,3,4-tetrahydropyridine-2-carboxylic acid residue. Another side reaction in this system was the cleavage of the amide bond between the Aea residue and the amino acid moiety preceding it resulting in the formation of a side product with a six-membered ring at the N-terminus (2,3,4,5-tetrahydropyridine-2-carboxylic acid residue). We found that, depending on the peptide sequence, one of those side products is predominant. Our work suggests new methods for the solid-state synthesis of peptides containing unnatural amino acids.

Mechanism and identification of reaction byproducts for the degradation of Chloramphenicol drug in heterogeneous photocatalytic process

The present work investigated the degradation behavior of chloramphenicol (CHPL) drug at a high concentration in the UV-TiO2 photocatalytic (UVPC) process to compare the performance of cleavage of CHPL molecule and total organic carbon (TOC) reduction. The reduction in TOC was mostly resulted from the cleavage of C-C homolytic bond which was in the accordance of LC-MS spectra. The TOC removal was trailed by 23.19% than CHPL with 100 mgL−1 using TiO2 1.25 gL−1, pH 3, and irradiation time of 45 min. The mechanistic routes of CHPL decomposition in the UVPC process are proposed and its synergy in the Fenton oxidation process is also explored. Total seven intermediates appeared in the mass spectra within the mass to charge ratio of 100–400. The proposed mechanism implied that intermediates were mostly originated by the decomposition of amide chain of CHPL molecule. The antimicrobial activity of CHPL towards the inactivation of E. coli XL 10GOLD was decreased by 67.4% after 45 min of decomposition.

Synthesis of silica@C-dots/phosphotungstates core-shell microsphere for effective oxidative-adsorptive desulfurization of dibenzothiophene with less oxidant

A core-shell microsphere catalyst with a solid silica core and a mesoporous shell made up of quaternary ammonium phosphotungstate and carbon dots (C-dots) was successfully synthesized for the oxidative-adsorptive desulfurization (OADS) of dibenzothiophene (DBT) in fuel oil. The phosphotungstic acid used for the synthesis of the catalyst was calcined to enhance its activity. XRD, FT-IR and catalytic test showed that the defective Keggin anion [PW12O38]3− formed under proper calcination conditions could explain the activity enhancement. EPR measurement indicated that hydroxyl radicals were generated from H2O2 by the interaction with C-dots, which proved C-dots to be an efficient cocatalyst in the system. The synergetic effect of [PW12O38]3− and C-dots in the synthesized catalyst remarkably improve the utilization efficiency of H2O2. When the loading amount of phosphotungstate and C-dots were optimized to 25% and 0.45%, the OADS system showed best desulfurization capacity under 50 °C. A high OADS efficiency of 98.08% could still be achieved even when the ratio of n(H2O2)/n(DBT) was reduced to 1.75. The existence of dibenzothiophene sulfoxide (DBTO) in the acetonitrile eluent of spent catalyst was confirmed by LC–MS spectra. The characterization results indicated that part of the DBT was oxidized to its corresponding sulfoxide which need less oxidant than sulfone. Both of the oxidation products could be eliminated from oil phase by adsorption on the catalyst.

Synthesis, structural exploration and Hirshfeld surface analysis of a novel bioactive heterocycle: (4-(6-Fluorobenzo[d]isoxazol-3-yl) piperidin-1-yl)(morpholino)methanone

Abstract The title compound, (4-(6-fluorobenzo[d]isoxazol-3-yl) piperidin-1-yl)(morpholino)methanone was prepared from 3-(piperidin-4-yl)benzo[d]isoxazole and evaluated for antiproliferative activity and structure was characterized using IR, 1H NMR, LC-MS spectra and finally the structure was confirmed by X-ray diffraction studies. The compound crystallizes in the monoclinic crystal system with the space group P21/c. The piperidine ring and the morpholine ring in the title compound adopt a chair conformation with the benzisoxazole ring in the planar conformation within the experimental limits. The molecular structure is stabilized by both inter and intra-molecular hydrogen bonds of the type C—H…O and C—H…N respectively which can account for the stability of the molecule. Further, Hirshfeld surface analysis employing 3D molecular surface contours and 2D fingerprint plots have been used to analyze intermolecular interactions present in the solid state of the crystal.

Combination of LC–MS based metabolomics and antioxidant activity for evaluation of bioactive compounds in Fragaria vesca leaves from Italy

Wild strawberry (Fragaria vesca) is recognized as a traditional food of Campania region (Italy). The vegetative parts have a pharmaceutical interest, being used as decoctions for hypertension treatment due their detoxifying, diuretic, stimulant and dermatological protective properties; leaves, that after collection of fruits are generally thrown away, could be an interesting byproduct, source of bioactive compounds for cosmetic and pharmaceutical industry. In the present work, the metabolite profiles of F. vesca leaves coming from populations spontaneously growing in the underwood (wild) and in crop (cultivated) and from autochthonous and non-autochthonous germplasm of Campania region (Italy) were investigated by LC-ESI/LTQOrbitrap/MS analysis. 27 metabolites mainly belonging to organic acids, flavonoids, catechin and its oligomers, and ellagitannins were putatively identified. Antioxidant activity was tested for each sample, in particular cultivated samples and wild samples with autochthonous germplasm of Campania region showed higher antioxidant activity compared to the non autochthonous ones. Moreover, in this study, it was possible to predict antioxidant metabolites, markers of this species, using LC–MS spectra and multivariate regression data analysis.

Immunomodulatory potential of nanocurcumin-based formulation.

Vitamins, minerals, and nanocurcumin play a substantial role in various nutraceutical/pharmaceutical formulations that are widely used in therapeutics, cosmetics, and dietary supplements. The current study aimed to investigate the comparative in vitro immunomodulatory effect of a novel nanocurcumin-based formulation with curcumin in LPS-induced cytokine expression, NK cells' activity, and phagocytosis. The proinflammatory cytokines (TNF-α, IL-1β, and MIP-1α) and NK cells' activity were measured in cell supernatants using ELISA assay; however, phagocytosis activity was performed using colorimetric analysis. The chemical characterization of novel nanocurcumin-based formulation using LC-MS (R t 19.02min) and mass spectra analysis (m/z 369.04) confirmed the presence of the curcumin in highest peak concentration. MTT assay in three tested cell-lines showed that the formulation was found non-toxic at all the tested concentrations. The expression of TNF-α, IL-1β, and MIP-1α in splenocytes was significantly (p≤0.001) inhibited. Besides, the NK cells' activity and phagocytosis (macrophage) were increased significantly (p≤0.001). Overall, the promising results of this study indicated the significant immunomodulatory effect of nanocurcumin-based formulation compared to the curcumin, which could be used against various inflammatory disorders such as allergy, asthma, autoimmune diseases, coeliac disease, inflammatory bowel disease, etc.

Isolasi, Identifikasi, Karakterisasi, dan Uji Antibiofilm Derivat Asam Galat dari Kulit Batang Sterculia quadrifida R.Br

Faloak (Sterculia quadrifida R.Br) is used empirically by residents of Timor island to treat hepatitis, typhoid, ulcers, and to restore stamina. Information of active compound contained in the bark of faloak specifically unpublished. This study aims to determine the active compound contained in faloak bark that can be used as antibiofilm. The extraction was performed by soxletation method, the isolation was performed by gradien t isolation method, the elusidation was performed by merging information from NMR and LC-MS spectra analysis. The biofilm inhibition activity test was performed by microdilution method formed on flat bottom flexible microplate U-bottom PVC 96 wells with staining using 1% crystal violet. The isolation process obtained 3 gallic acid derivatives, named isolate 1, isolate 2, and isolate 3. Test of inhibition of biofilm formation showed isolate 1 has IC 50 of 46,87 µg/mL, isolate 2 has IC 50 of 45,87 µg/mL, and isolate 3 has IC 50 42,65 µg/mL. The biofilm test results showed that isolates 1-3 had high biofilm inhibition potency.

СИНТЕЗ ТА БІОЛОГІЧНА АКТИВНІСТЬ НОВИХ ПОХІДНИХ 5-АМІНОМЕТИЛЕН-2-ТІОКСОТІАЗОЛІДИН-4-ОНІВ

Мета роботи. Синтез нових похідних 5-амінометилен-2-тіоксотіазолідин-4-онів як перспективних сполук для хімічних перетворень та фармакологічного скринінгу.Матеріали і методи. Ключові вихідні реагенти синтезовані за відомими методиками із комерційно доступних реактивів. Спектри ПМР одержаних сполук знімались на приладі Varian VXR-400, розчинник DMSO-d6, стандарт - тетраметилсилан. LC-MS спектри отримані на приладі Finnigan MAT INCOS-50. Дані елементного аналізу на вміст карбону, гідрогену та нітрогену відповідають розрахованим (±0,3%). Температуру плавлення визначали на приладі BŰCHI B-545. Вивчення протитрипаносомної активності сполук in vitro проводилося в Національному музеї історії природи (Франція) та полягало у визначенні інгібуючої концентрації ІС50 сполук на штамі Trypanosoma brucei brucei (TBB). Дослідження протимікробної активності іn vitro проводилося методом дифузії в агар. Визначення протипухлинної активності синтезованих сполук виконувалось у рамках міжнародної наукової програми DTP (Developmental Therapeutic Program) Національного інституту раку (NCI, Бетезда, Меріленд, США).Результати й обговорення. На основі раніше запропонованого синтетичного підходу до 5-R,R'- амінометиленпохідних-4-тіазолідинонів отримано серію 5-амінометилен-2-тіоксотіазолідин-4-онів (5-амінометил- енроданінів). Вперше запропоновано ефективний метод синтезу 5-амінометилен-2-тіоксотіазолідин-4-ону, який базується на амінолізі відповідного 5-етоксиметилензаміщеного при дії гідрокарбонату амонію в спиртовому середовищі. Вперше досліджено реакційну здатність 5-феніл-3,4-дигідро-2Н-піразол-3-карбонової кислоти в реакції амінолізу з 5-етоксиметилен-2-тіоксотіазолідин-4-оном. Структура синтезованих сполук підтверджена комплексом методів ЯМР- та мас-спектрометрій. Досліджено in vitro антитрипаносомну, протимікробну та протипухлинну активність синтезованих сполук.Висновки. Запропоновано методи синтезу та отримано ряд оригінальних похідних з 5-амінометиленроданіновим каркасом як перспективних реагентів для хімічних перетворень та потенційних об’єктів для фармакологічного скринінгу. Ідентифіковано сполуки-хіти для дизайну потенційних антитрипаносомних та протимікробних агентів.

НОВІ НЕКОНДЕНСОВАНІ ПІРИДИН-ТІАЗОЛ/ТІАЗОЛІДИНОНИ ТА ЇХ ПРОТИТРИПАНОСОМНА АКТИВНІСТЬ

Мета роботи. Здійснити синтез нових неконденсованих піридин-тіазол/тіазолідинонів та провести дослідження їх протитрипаносомної активності in vitro.Матеріали і методи. Вихідні реагенти синтезовані за відомими методиками із комерційно доступних реактивів. 1Н та 13С ЯМР спектри знімали на приладах Varian Gemini 400 MHz та Varian Mercury-400 100 MHz, відповідно. Хромато-мас-спектри одержано на спектрометрі Agilent 1100 Series LCMS. Температуру плавлення визначали на приладі BÛCHI B-545.Результати й обговорення. На основі реакцій [2+3]-циклоконденсації одержано серії похідних тіазолу, тіазоліну та 5-заміщених 4-тіазолідинонів із піридиновим фрагментом у молекулах. Як S,N-бінуклеофіли використано тіосемікарбазони 3- та 4-піридинкарбальдегідів, а як еквіваленти діелектрофільного синтону [C2]2+ α-галогенокарбонові кислоти, етил-2-хлорацетоацетат, метил-2-бромо-3-(3-метилфеніл)пропіонат та малеїніміди. Скринінг антитрипаносомної активності in vitro на штамах Trypanosoma brucei gambiense дозволив ідентифікувати високоактивне неконденсоване похідне фуран-піридин-тіазоліну, що володіє трипаноцидним ефектом в мікромолярній концентрації (IC50 = 3.32 мкМ), а також перспективні для оптимізації ефекту 5-етил-2-(піридинілметиленгідразин)тіазол-4-они.Висновки. Вперше одержано нові неконденсовані піридин-тіазоли/тіазолідинони як перспективні агенти для фармакокорекції сонної хвороби.

Different Hemi-Salen/Salan Ligand Containing Binuclear Boron-Fluoride Complexes: Synthesis, Spectroscopy, Fluorescence Properties, and Catalysis

ABSTRACTA family of hemi-salen (L1H–L6H) and hemi-salan (L1aH–L2aH) ligands-based N,O-chelated binuclear boron-fluoride [Ln(BF2)2] (n = L1–L6 or L1a–L2a) complexes have been prepared and characterized by a variety of spectroscopic techniques (1H, 13C and 19F NMR, FT-IR, UV-Vis, LC-MS, and fluorescence spectra) and elemental analysis. All of the binuclear boron-fluoride complexes exhibit strong absorption bands due to S0→S1 transitions and strong fluorescence properties were observed at room temperature in the solution. The binuclear boron complexes containing two naphthyl groups are significantly red-shifted in comparison with the other binuclear boron-fluoride complexes. After the structures are characterized, these hemi-salen and salan ligand-based N, O-chelated binuclear boron-fluoride complexes were utilized to the transfer hydrogenation of the different acetophenone derivatives conversion to 1-phenylethanol derivatives as catalysts.

The synthesis and the antimicrobial activity of the substituted aryl amides of 3-arylmethyl-2,4- dioxo-1,3,7-triazaspiro[4.4]nonane-7-carboxylic acids

By the interaction of the substituted aryl isocyanates with the series of 3-arylmethyl-1,3,7-triazaspiro[ 4.4]nonane-2,4-diones in the propanol-2 medium the series of the substituted aryl amides of 3-arylmethyl-2,4-dioxo-1,3,7-triazaspiro[4.4]nonane-7-carboxylic acids have been obtained. The structure of the products obtained has been confirmed by the instrumental methods of the analysis, such as 1Н, 13С NMR- and chromato-mass spectrometry. The 1Н NMR-spectra of all of the substances obtained contain the signal of the methylene group of the arylmethyl fragment at 4.5 ppm as a singlet; the number and splitting of the signal in the range of the aromatic protons resonance well corresponds with the substitution in the aromatic part of the molecule; the protons of the NHCO urea fragment with the signal of the NH at position 1 are observed as two singlet signals at 7.4-8.2 and 8.9 ppm. The 13C NMR-spectra of all compounds obtained contain four signals at 35, 45, 54 and 65 ppm of the pyrrolidine cycle of the molecules; three signals of the carbonyl groups carbon atoms are observed at 154, 155 and 174 ppm. The LC-MS spectra of the target compounds contain the peaks of [M+H]+ ions, which masses are in good accordance with the structures proposed. The results of the antimicrobial activity screening show the ability of the compounds synthesized to inhibit the growth of the Candida albicans fungi strain. The gram-positive microorganisms such as the strains of Staphylococcus aureus and Bacillus subtilis are found to be sensitive to the compounds containing the methyl groups as substituents in the arylmethyl fragments of the molecule.

Studies on the probing stimulants for the white-backed planthopper, Sogatella furcifera (Homoptera: Delphacidae) in rice plant (Oryza sativa L.).

To elucidate the probing stimulants in rice plants for the white-backed planthopper, Sogatella furcifera, bioassay-guided separations were conducted, which led to the isolation of four active compounds. Using NMR and LC-MS spectra, their structures were determined as isoorientin 2″-O-(6‴-(E)-feruloyl)glucoside, isoorientin 2″-O-(6‴-(E)-p-coumaroyl)glucoside, tricin 5-O-glucoside, and isoscoparin 2″-O-(6‴-(E)-feruloyl)glucoside.

Fast and Reliable Quantitative Peptidomics with labelpepmatch.

The use of stable isotope tags in quantitative peptidomics offers many advantages, but the laborious identification of matching sets of labeled peptide peaks is still a major bottleneck. Here we present labelpepmatch, an R-package for fast and straightforward analysis of LC-MS spectra of labeled peptides. This open-source tool offers fast and accurate identification of peak pairs alongside an appropriate framework for statistical inference on quantitative peptidomics data, based on techniques from other -omics disciplines. A relevant case study on the desert locust Schistocerca gregaria proves our pipeline to be a reliable tool for quick but thorough explorative analyses.