High-resolution Electron Ionization Mass Research Articles

Cytotoxicity of sesquiterpenes ferulenol and coladin on liver FAO and B16F1 melanoma cells

Background: Ferula vesceritensis is an indigenous plant of Algerian Sahara riche in sesquiterpene coumarins. Objective: In this study, we investigated the biological activity of sesquiterpene coumarins; coladin, ferulenol, and lapiferin (10_-acetoxy-6_-angeloyloxy-8_,9_-epoxy-trans-caxotan-4_-ol) isolated for the first time from the crude extract CH2Cl2—MeOH (1:1) of the roots of F. vesceritensis Coss. et Dur. Materials and Methods: Structures of coladin, ferulenol, and lapiferin were determined by extensive nuclear magnetic resonance (NMR) analyses, including 1D-(1H and13C) and 2D-NMR experiments (correlation spectroscopy, heteronuclear single-quantum coherence, heteronuclear multiple bond correlation (HMBC), and nuclear overhauser effect spectroscopy) as well as high-resolution electron ionization mass spectra and mass spectroscopy analyses. Results: Tested on mouse B16F1 melanoma cells, ferulenol, coladin, and lapiferin exhibited a significant decrease in cell proliferation and a decrease of mitochondrial dehydrogenase activity evaluated on living FAO cells and B16F1 melanoma cells with the WST-1 throughout an apoptotic pathway. They displayed pro-apoptotic effects observed by a decrease in mitochondrial membrane potential and the mitochondrial respiratory rate on isolated liver mitochondria in a dose-dependent manner. Conclusion: Our results highlight the importance of the sesquiterpene coumarins extracted from F. vesceritensis as new biologically active natural products against cancer cells. Abbreviations used: FAO: Hepatoma cell line; B16F1: Pulmonary metastasis melanoma cell line.

New Resorcinol Derivatives from a Sponge-Derived Fungus Hansfordia sinuosae.

Ten new resorcinol derivatives named hansfordiols A-J (1-10) were isolated from the fermentation broth of the sponge-derived fungus Hansfordia sinuosae. High resolution electron ionization mass spectrometry, FT-IR spectroscopy, and NMR techniques were used to elucidate the structures of these compounds, and the absolute configurations were established by the modified Mosher's method and their specific optical rotation. The structures of compounds 8-10 were featured with various chlorination at aromatic rings. Their antioxidant activities on ABTS, cytotoxicity on the HCT-8, Bel-7402, BGC-823, A549, and A2780 cell lines, and antibacterial activities were evaluated.

Prediction Models of Retention Indices for Increased Confidence in Structural Elucidation during Complex Matrix Analysis: Application to Gas Chromatography Coupled with High-Resolution Mass Spectrometry.

Monitoring of volatile and semivolatile compounds was performed using gas chromatography (GC) coupled to high-resolution electron ionization mass spectrometry, using both headspace and liquid injection modes. A total of 560 reference compounds, including 8 odd n-alkanes, were analyzed and experimental linear retention indices (LRI) were determined. These reference compounds were randomly split into training (n = 401) and test (n = 151) sets. LRI for all 552 reference compounds were also calculated based upon computational Quantitative Structure-Property Relationship (QSPR) models, using two independent approaches RapidMiner (coupled to Dragon) and ACD/ChromGenius software. Correlation coefficients for experimental versus predicted LRI values calculated for both training and test set compounds were calculated at 0.966 and 0.949 for RapidMiner and at 0.977 and 0.976 for ACD/ChromGenius, respectively. In addition, the cross-validation correlation was calculated at 0.96 from RapidMiner and the residual standard error value obtained from ACD/ChromGenius was 53.635. These models were then used to predict LRI values for several thousand compounds reported present in tobacco and tobacco-related fractions, plus a range of specific flavor compounds. It was demonstrated that using the mean of the LRI values predicted by RapidMiner and ACD/ChromGenius, in combination with accurate mass data, could enhance the confidence level for compound identification from the analysis of complex matrixes, particularly when the two predicted LRI values for a compound were in close agreement. Application of this LRI modeling approach to matrixes with unknown composition has already enabled the confirmation of 23 postulated compounds, demonstrating its ability to facilitate compound identification in an analytical workflow. The goal is to reduce the list of putative candidates to a reasonable relevant number that can be obtained and measured for confirmation.

Synthesis and Characterization of a Series of 1-Aryl-4-[Aryldiazenyl]-piperazines. Part II1. 1-Aryl-4-(2-Aryl-1-Diazenyl)-piperazines with Fluoro-, chloro-, Methyl-, Cyano- and Acetyl Substituents in The 1-Aryl Group

This paper reports the synthesis and characterization of eight series of 1-aryl-4-(2-aryl-1-diazenyl)-piperazines (12 to 19). Several series of these triazenes have been synthesized by the diazotization of a primary arylamine followed by diazonium coupling with a secondary arylpiperazine . The arylpiperazines used in this study are: 1-phenylpiperazine, 1-(4-fluorophenyl-)piperazine, 1-(4-chlorophenyl-)piperazine, 1-(3,4-dichlorophenyl-)piperazine, 1-(2-methylphenyl-)-piperazine, 1-(4-acetophenyl-)-piperazine, 1-(2-pyridyl-)piperazine and 2-cyanophenylpiperazine. These new triazenes (series 12-19) have been identified with a cocktail of contemporary spectroscopic techniques, notably infra-red and nuclear magnetic spectroscopy, supported by high resolution electron ionization mass spectrometry.

Mass spectrometry studies of lycodine-type Lycopodium alkaloids: sauroxine and N-demethylsauroxine.

Sauroxine and N-demethylsauroxine are lycodine-type Lycopodium alkaloids. In recent years, Lycopodium alkaloids have gained significant interest due to their unique skeletal characteristics as well as due to their acetylcholinesterase activity. It is known that drugs that inhibit acetylcholinesterase can be used to treat the early stages of Alzheimer's disease. Sauroxine and N-demethylsauroxine were isolated from the aerial parts of Huperzia saururus (Lam.) Trevis. Electron ionization mass spectrometry (EI-MS) (low resolution) and collision-induced dissociation tandem mass spectrometry (CID-MS/MS) fragmentation was conducted using an ion trap, GCQ Plus mass spectrometer with MS/MS. Electron ionization high-resolution mass spectrometry (EI-HRMS) was performed in a magnetic sector mass spectrometer (Micromass VG). Using GC/EI-CID-MS/MS we obtained different fragmentation routes that connect all the ionic populations. In addition, the use of EI-HRMS allowed us to measure the exact masses of all the fragment ions, and, with all this information gathered, we tried to establish a fragmentation scheme concordant with the ascendant and descendant species. The mass spectrometry studies presented in this work complete our mass studies of Lycopodium alkaloids. The mass spectrometry work presented has been very useful to confirm the structures as well as to support the biogenetic relationships between the lycodine-type Lycopodium alkaloids: sauroxine and N-demethylsauroxine.

Simultaneous detection of multiple hydroxylated polychlorinated biphenyls from a complex tissue matrix using gas chromatography/isotope dilution mass spectrometry

In this study, we developed a comprehensive, highly sensitive, and robust method for determining 53 congeners of three to eight chlorinated OH-PCBs in liver and brain samples by using isotope dilution gas chromatography (GC) coupled with electron capture negative ionization mass spectrometry (ECNI-MS). These results were compared with those from GC coupled with electron ionization high-resolution mass spectrometry (EI-HRMS). Clean-up procedures for analysis of OH-PCBs homologs in liver and brain samples involve a pretreatment step consisting of acetonitrile partition and 5% hydrated silica-gel chromatography before derivatization. Recovery rates of tri- and tetra-chlorinated OH-PCBs in the acetonitrile partition method followed by the 5% hydrated silica-gel column (82% and 91%) were higher than conventional sulfuric acid treatment (2.0% and 3.5%). The method detection limits of OH-PCBs for each matrix obtained by GC/ECNI-MS and GC/EI-HRMS were 0.58-2.6 pg g(-1) and 0.36-1.6 pg g(-1) wet wt, respectively. Recovery rates of OH-PCB congeners in spike tests using sample matrices (10 and 50 pg) were 64.7-117% (CV: 4.7-14%) and 70.4-120% (CV: 2.3-12%), respectively. This analytical method may enable the simultaneous detection of various OH-PCBs from complex tissue matrices. Furthermore, this method allows more comprehensive assessment of the biological effects of OH-PCB exposure on critical organs.

Effect of seaweed epibiotic bacterium Streptomyces violaceoruber SCH-09 on marine fouling organisms

Seaweed-associated bacteria play a role in helping to protect host organisms from biofouling by producing anti-fouling compounds. In a first step to develop such anti-fouling compounds, we isolated epibiotic bacteria from seaweed and subsequently screen culture extracts for anti-fouling activities. The active epibiotic bacterium studied was isolated from Undaria pinnatifida and identified as Streptomyces violaceoruber based on 16S rDNA sequence analysis. Two active compounds were isolated from the culture extracts by silica gel chromatography and high-performance liquid chromatography, and their structures were analyzed by nuclear magnetic resonance and high-resolution electron ionization mass spectrometry. The compounds were identified as furanone derivatives: 3-octa-1′,3′-dienyl-4-methylfuran-2(5H)-one and 3-octa-1′-enyl-4-methylfuran-2(5H)-one, respectively. These compounds showed anti-fouling activities against the following fouling organisms: zoospores of Ulva pertusa, the diatom Navicula annexa, and the mussel Mytilus edulis, with an EC50 (minimum concentration for 50 % spore inhibition) range of 0.02–0.1 μg/ml. In the acute toxicity tests on juvenile rockfish Shebastes shlegelli, brine shrimp Artemia salina, and microalga Tetraselmis suecica, the two compounds showed LC50 (concentration lethal to 50 % of the spores) ranges of 13.9–118.9 and 14.8–81.9 μg/ml, respectively.

Two new phenethanol glycosides from Ligustrum robustum

Two new phenethanol glycosides, named ligurobustoside P (1), ligurobustoside Q (2) have been isolated from the leaves of Ligustrum robustum, together with the known compound angoroside A (3) which was firstly isolated from this species. The structures of the two new phenethanol glycosides (1–2) were elucidated by a combination of high-resolution electron ionization mass spectrometry (HR-ESI-MS), 1H NMR, 13C NMR, HMQC, and HMBC spectra for the first time.

Identification of Compounds in Commercial Kava Extracts by Gas Chromatography with Electron Ionization High-Resolution Mass Spectrometry

This paper discusses the identification of kava lactones and related compounds by gas chromatography (GC) and quadrupole time-of-flight mass spectrometry (QTOFMS) with an electron ionization source. Three herbal preparations from different sources were analyzed by both GC-low-resolution MS and GC-high-resolution MS. The exact mass measurements generated with a research QTOFMS with mass accuracies in the low ppm range were combined with the isotope abundance ratios to confirm the presence of kava lactones and to identify additional compounds present in the Kava extracts. Although the availability of standards is of upmost importance to unequivocally confirm compound identities, the combination of accurate mass ( 10,000) and literature information on the approximate composition of the herbal extracts provides a powerful analytical tool to help identify organic compounds in herbal extracts.

Complete assignments of 1H and 13C NMR data for new dibenzocyclooctadiene lignans from Kadsura oblongifolia

Two new dibenzocyclooctadiene lignans, named kadoblongifolins A (1) and B (2), and one new natural product dibenzocyclooctadiene lignan, named kadoblongifolin C (3), were isolated from the stems of Kadsura oblongifolia (K. oblongifolia), together with five known ones, schizanrin F (4), propinquanin C (5), schisantherin G (6), heteroclitin Q (7), kadsurarin (8). The structures of these new lignans were elucidated by a combination of high-resolution electron ionization mass spectrometry (HR-EI-MS), (1)H NMR, (13)C NMR, HMQC, HMBC, and NOESY spectra.

1H and 13C NMR assignments for 6‐demethylvermistatin and two penicillide derivatives from the mangrove fungus Guignardia sp. (No. 4382) from the South China Sea

One new compound 6-demethylvermistatin (1), together with two known compounds, the penicillide derivatives (2) and (3) were isolated from the mangrove fungus Guignardia sp. No. 4382 obtained from the South China Sea. Their structures were assigned using high-resolution electron ionization mass spectrometry(HREIMS), (1)H and (13)C NMR spectra, DEPT, and by 2D COSY, HMQC, and HMBC experiments. The absolute configuration of 1 was established by comparison of its CD with that of vermistatin.

Elemental Analysis of Organic Species with Electron Ionization High-Resolution Mass Spectrometry

We present a new elemental analysis (EA) technique for organic species (CHNO) that allows fast on-line analysis (10 s) and reduces the required sample size to approximately 1 ng, approximately 6 orders of magnitude less than standard techniques. The composition of the analyzed samples is approximated by the average elemental composition of the ions from high-resolution electron ionization (EI) mass spectra. EA of organic species can be performed on organic/inorganic mixtures. Elemental ratios for the total organic mass, such as oxygen/carbon (O/C), hydrogen/carbon (H/C), and nitrogen/carbon (N/C), in addition to the organic mass to organic carbon ratio (OM/OC), can be determined. As deviations between the molecular and the ionic composition can appear due to chemical influences on the ion fragmentation processes, the method was evaluated and calibrated using spectra from 20 compounds from the NIST database and from 35 laboratory standards sampled with the high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The analysis of AMS (NIST) spectra indicates that quantification of O/C is possible with an error (average absolute value of the relative error) of 30% (17%) for individual species. Precision is much better than accuracy at +/-5% in the absence of air for AMS data. AMS OM/OC has an average error of 5%. Additional calibration is recommended for types of species very different from those analyzed here. EA was applied to organic mixtures and ambient aerosols (sampled at 20 s from aircraft). The technique is also applicable to other EI-HRMS measurements such as direct injection MS.

A Sesquineolignan with a Spirodienone Structure from Pinus sylvestris L.

Barking up the right tree: The spirodienone sesquineolignan pinobatol (1), a long-time speculated monomeric unit of lignin, was isolated from the 70 % aqueous acetone extract of pine (Pinus sylvestris L.) bark. Its structure was determined by high-resolution electron ionization mass spectrometry and a variety of NMR spectroscopic techniques.

Identification and Quantification of Polybrominated Hexahydroxanthene Derivatives and Other Halogenated Natural Products in Commercial Fish and Other Marine Samples

During routine analysis of commercial fish on halogenated pollutants, an unknown tribromo component (TriBHD) was initially detected as an abundant peak in sample extracts from the Mediterranean Sea. The molecular formula was established to be C16H19Br3O by gas chromatography with electron ionization high-resolution mass spectrometry (GC/EI-HRMS). GC/EI-MS data were virtually identical with a polybrominated hexahydroxanthene derivative (PBHD) previously isolated from an Australian sponge species known to occur in the Mediterranean Sea as well. A tetrabromo isomer (TetraBHD) was also found in the fish samples. The concentrations of TriBHD and other halogenated compounds in commercial fish (sea bass, gilt head bream, anchovy, sardine, and salmon) were estimated with GC/electron capture detection (ECD). Using the ECD response of trans-nonachlor, the concentration of TriBHD reached up to 90 ng/g lipid weight and accounted for up to >90% of the concentration of p,p'-DDE, which was the most abundant peak in the most samples investigated. On the basis of the GC/ECD response, TetraBHD amounted for approximately 1/7 of TriBHD in all fish samples investigated. The sample with the highest content was a green-lipped mussel from New Zealand (236 ng/g lipid weight). The halogenated natural products TBA, Q1, and MHC-1 were also present in most of the samples. We assume that the bulk of the residues in fish from aquaculture may originate from algae and sponges living in proximity of the fish farms. Detection of TriBHD and TetraBHD in blubber of a monk seal (Monachus monachus) suggests that both HNPs may reach the top predators of food webs and thus also humans.

Croton lobatus, an African medicinal plant: Spectroscopic and chemical elucidation of its many constituents

The chemical constituents of the African medicinal plant Croton lobatus were elucidated and characterised using 1D and 2D-NMR analysis and the application of the technique of High Resolution Electron Ionization Mass Spectrometry (HREIMS) and High Resolution Mass Spectrometry (HRMS). The novel triglyceride lobaceride or 3-((6Z,9Z)dodeca-6,9-dienoyloxy)-2-octanoyloxypropyl (6Z,9Z)dodeca-6,9-dienoate, along with ten compounds were isolated from the stems and leaves of Croton lobatus.

Identification of protein biomarkers in the pyrolysis electron ionization high-resolution mass spectrum of Brucella neotomae

Pyrolysis electron ionization high resolution mass spectrometry (Py-EI-HR-MS) has been previously used to identify the source of lipid, carbohydrate and nucleic acid peaks from whole bacterial cells and standards. Py-EI-HR-MS has proven to be a powerful technique for examining biomarker ions in a complex mixture, since most nominal pyrolysis mass spectral peaks are composed of several contributing species. Empirical formula from high-resolution MS data generated from Brucella neotomae, amino acids and proteins for a series of Py-low-resolution mass spectral peaks ( m/ z 67, 76, 79, 89, 93, 95, 103, 105, 115, 117, 129, and 131) have been calculated. These peaks had been previously found to be statistically important in chemically distinguishing various bacteria. Mechanisms for the formation of pyrolysis and/or electron ionization fragments from the bacterial proteins are presented for ions that were common to the amino acids, protein standards and the bacterial data.

Evidence for fullerenes in solid bitumen from pillow lavas of Proterozoic age from Mítov (Bohemian Massif, Czech Republic)

Andesitic pillow lavas containing biogenic, solid bitumen (SB) are a constituent of a Neoproterozoic volcanosedimentary sequence (Teplá-Barrandian unit, Bohemian Massif) in the Mítov area of the Czech Republic. A black shale formation that is crosscut by these andesitic basalts is 565 Ma old. Carbon disulfide extracts of two powdered samples of SB contain 0.2 and 0.3 ppm of C 60, respectively, as determined by high-pressure liquid chromatography. The peak assignment based on retention time is fully supported by high-resolution electron ionization mass spectrometry (EI-MS). No C 70 was detected, nor was C 60 found in two other SB samples from this locality. Other investigated carbonaceous samples from Bohemia (coals and anthracites of Upper Paleozoic age and anthraxolite, graphitoids, and graphite of Upper Proterozoic age) did not contain fullerenes at concentrations above the detection limit of 0.01 ppm. The absence of C 60 in these samples was confirmed by EI-MS. The proposed mechanism of fullerene formation involves a primary algal phase, generation of a hydrocarbonaceous mixture in the course of thermal evolution of the sedimentary series, and their high-temperature transformation related to the extrusion of basalt. An important feature for fullerene conservation was the enclosure of fullerenes in SB with a structure similar to glasslike carbon, where the fullerene was protected against oxidation.

Tris(hydridosilylethyl)boranes: highly reactive synthons for polymeric silicon compounds

Abstract Two methods for the synthesis of tris(hydridosilylethyl)boranes B[C2H4Si(CH3)nH3−n]3 (C2H4=CHCH3, CH2CH2; n=0, 1, 2; 5a–c) are reported. In the first route, tris(chlorosilylethyl)boranes B[C2H4Si(CH3)nCl3−n]3 (n=0, 1, 2; 3a–c) are reacted with LiAlH4 in diethyl ether solution. Compounds 3a–c are prepared by hydroboration of the respective vinyl chlorosilanes (H2CCH)Si(CH3)nCl3−n (n=0, 1, 2; 1a–c) with borane dimethylsulfide, BH3·S(CH3)2. Hydroboration of hydrido vinylsilanes (H2CCH)Si(CH3)nH3−n (n=0, 1, 2; 6a–c) with BH3·S(CH3)2 represents an alternative route, which produces 5a–c in much higher yield. The intermediates 6a–c are obtained from 1a–c and LiAlH4 in diethyl ether solution and, because of their difficult handling, reacted in situ. Detailed NMR studies prove boron addition to the olefinic moieties to be not regioselective, since resonance signals for products formed by α- and β-boron addition to the vinyl functions are observed. The elemental constitution of 5a–c is established by high-resolution electron ionization mass spectrometry for both the molecular ion peak and a series of fragment ions. Major fragments arise from CC bond formation in the gas phase between two of the boron side chains in the ion dipole complex.

A novel rearrangement in the gas phase under electron ionization for 3-glycosyl-5-aryl-2-isoxazolines

Some 3-glycosyl-5-aryl-2-isoxazolines were studied in the gas phase under electron ionization (EI) conditions in order to elucidate their behavior. These derivatives showed an interesting rearrangement involving opening of the heterocyclic ring with a concomitant ring closing to afford a new isoxazoline derivative. The first step of this reaction was the less common cleavage of the heterocyclic C(5)-O bond. The 5-aryl substituent was responsible for the pseudobenzylic stabilization of the new isoxazoline derivative. EI tandem mass spectrometry and EI high-resolution mass spectrometry allowed the elucidation of fragmentation pathways. Copyright 1999 John Wiley & Sons, Ltd.

Assessment of polychlorinated naphthalenes in aquifer samples for drinking water purposes.

Polychlorinated naphthalenes (PCNs) were identified and quantified in water samples collected from the aquifer of the Llobregat river near Barcelona (NE Spain) in order to establish the source and extent of spreading of the contamination. Many of the identified PCNs were well resolved as single peaks on the chromatograms recorded using high resolution gas chromatography combined with electron ionization high resolution mass spectrometry and single-ion monitoring. The profile and pattern of PCNs found in groundwater samples are similar to those of Halowax 1099. The levels of the sum of mono- to octachloronaphthalenes in the water samples ranged from 0.003 microgram/L to 72.9 micrograms/L.