Novel sesquiterpene lactones from Eremanthus seidelii

Two novel sesquiterpene lactones were isolated from crude extract of the Eremanthus seidelii leaves. Reliable structural elucidations to these lactones were established by 1D and 2D NMR spectroscopic techniques and high-resolution electrospray mass spectrometry data. (C) 2012 Elsevier Ltd. All rights reserved.

Nanoassisted Laser Desorption-Ionization-MS Imaging of Tumors

The ability of nanoassisted laser desorption-ionization mass spectrometry (NALDI-MS) imaging to provide selective chemical monitoring with proper spatial distribution of lipid profiles from tumor tissues after plate imprinting has been tested. NALDI-MS imaging identified and mapped several potential lipid biomarkers in a murine model of melanoma tumor (inoculation of B16/F10 cells). It also confirmed that the in vivo treatment of tumor bearing mice with synthetic supplement containing phosphoethanolamine (PHO-S) promoted an accentuated decrease in relative abundance of the tumor biomarkers. NALDI-MS imaging is a matrix-free LDI protocol based on the selective imprinting of lipids in the NALDI plate followed by the removal of the tissue. It therefore provides good quality and selective chemical images with preservation of spatial distribution and less interference from tissue material. The test case described herein illustrates the potential of chemically selective NALDI-MS imaging for biomarker discovery.

Thermal behavior of malonylglucoside isoflavones in soybean flour analyzed by RPHPLC/DAD and eletrospray ionization mass spectrometry

Soybean (Glycine max (Merrill) L) contains high content of aglycone isoflavones, as well as glucoside and malonylconjugates. In this work, the content of isoflavones in defatted soy flour was determined by reversed-phase high-performance liquid chromatography (RPHPLC) after alcoholic extraction in methanol/water mixture in the ratio 80:20 (v/v). It was observed that the heating treatment transformed the malonylglucosides into glucoside isoflavones. After heat treatment at 121 degrees C for 30 min, nearly all malonylisoflavones were converted into glucoside, but acetylisoflavones were not detected via RPHPLC analysis. Electrospray ionization mass spectrometry confirmed the presence of malonylisoflavones in heat-treated defatted soy flour by direct infusion analysis. (c) 2012 Elsevier Ltd. All rights reserved.

Oxidation of lysergic acid diethylamide (LSD) by peroxidases: a new metabolic pathway

Lysergic acid diethylamide (LSD) is a potent hallucinogen that is primarily metabolized to 2-oxo-3-hydroxy-LSD (O-H-LSD) and N-desmethyl-LSD (nor-LSD) by cytochrome P450 complex liver enzymes. Due to its extensive metabolism, there still is an interest in the identification of new metabolites and new routes of its metabolism in humans. In the present study, we investigated whether LSD could be a substrate for horseradish peroxidase or myeloperoxidase (MPO). Using liquid chromatography coupled to UV detection and electrospray ionization mass spectrometry (LC-UV-ESI-MS), we found that both peroxidases were capable of metabolizing LSD to the same compounds that have been observed in vivo (i.e., O-H-LSD and nor-LSD). In addition, we found another major metabolite, N,N-diethyl-7-formamido-4-methyl-6-oxo-2,3,4,4a,5,6-hexahydrobenzo[f]quinoline-2-carboxamide (FOMBK), which is an opened indolic ring compound. Hydrolysis of FOMBK led to the deformylated compound 7-amino-N,N-diethyl-4-methyl-6-oxo-2,3,4,4a,5,6-hexahydrobenzo[f]quinoline-2-carboxamide. The reactions of LSD with the peroxidases were chemiluminescent and sensitive to inhibition by reactive oxygen scavengers, which indicated that the classic peroxidase cycle is involved in this new alternative metabolic pathway. Considering that MPO is abundant in immune cells and also present in the central nervous system, the degradation pathway described in this study suggests a possible route of LSD metabolism that may occur concurrently with the in vivo reaction catalyzed by the cytochrome P450 system.

STUDY BY MASS SPECTROMETRY OF SOLUTIONS OF [HYDROXY(TOSYLOXY)IODO]BENZENE: PROPOSED DISPROPORTIONATION MECHANISMS

STUDY BY MASS SPECTROMETRY OF SOLUTIONS OF [HYDROXY(TOSYLOXY)IODO]BENZENE: PROPOSED DISPROPORTIONATION MECHANISMS. Solutions of [hydroxy(tosyloxy)iodo]benzene (HTIB or Koser's reagent) in acetonitrile were analyzed using high resolution electrospray ionization mass spectrometry (ESI-MS) and electrospray ionization tandem mass spectrometry (ESI-MS/MS) under different conditions. Several species were characterized in these analyses. Based on these data, mechanisms were proposed for the disproportionation of the iodine(III) compounds in iodine(V) and iodine(I) species.

Synthesis and characterization of a diruthenium(II,III)-ketoprofen compound and study of the in vitro effects on CRC cells in comparison to the naproxen and ibuprofen derivatives

A new diruthenium(II,III) complex, of formula [Ru2Cl(ket)(4)], Ruket, containing the non-steroidal anti-inflammatory drug ketoprofen was synthesized and mainly characterized by electrospray ionization mass spectrometry (ESI-MS), UV-Vis-IR electronic spectroscopy and FTIR and Raman vibrational spectroscopies. The four drug-carboxylato bridging ligands stabilize a Ru-2(II,III) mixed valent core in a paddlewheel type structure as confirmed by ESI mass spectra, electronic and vibrational spectroscopies and magnetic measurements. Ruket and the analogous compounds containing ibuprofen, Ruibp, and naproxen, Runpx, were tested for the biological effects in the human colon carcinoma cells HT-29 and Caco-2 expressing high and low levels of COX-2 respectively. All compounds only weakly affected the proliferation of the colorectal cancer cells HT-29 and Caco-2, and similarly only partially inhibited the production/activity of MMP-2 and MMP-9 by HT-29 cells, suggesting that COX-2 inhibition by these drugs can only partially be involved in the pharmacological effects of these derivatives. (c) 2012 Elsevier Ltd. All rights reserved.

Gas-phase reactivity of 2-hydroxy-1,4-naphthoquinones: a computational and mass spectrometry study of lapachol congeners

In order to understand the influence of alkyl side chains on the gas-phase reactivity of 1,4-naphthoquinone derivatives, some 2-hydroxy-1,4-naphthoquinone derivatives have been prepared and studied by electrospray ionization tandem mass spectrometry in combination with computational quantum chemistry calculations. Protonation and deprotonation sites were suggested on the basis of gas-phase basicity, proton affinity, gas-phase acidity (?Gacid), atomic charges and frontier orbital analyses. The nature of the intramolecular interaction as well as of the hydrogen bond in the systems was investigated by the atoms-in-molecules theory and the natural bond orbital analysis. The results were compared with data published for lapachol (2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone). For the protonated molecules, water elimination was verified to occur at lower proportion when compared with side chain elimination, as evidenced in earlier studies on lapachol. The side chain at position C(3) was found to play important roles in the fragmentation mechanisms of these compounds. Copyright (c) 2012 John Wiley & Sons, Ltd.

Protomers: formation, separation and characterization via travelling wave ion mobility mass spectrometry

Travelling wave ion mobility mass spectrometry (TWIM-MS) with post-TWIM and pre-TWIM collision-induced dissociation (CID) experiments were used to form, separate and characterize protomers sampled directly from solutions or generated in the gas phase via CID. When in solution equilibria, these species were transferred to the gas phase via electrospray ionization, and then separated by TWIM-MS. CID performed after TWIM separation (post-TWIM) allowed the characterization of both protomers via structurally diagnostic fragments. Protonated aniline (1) sampled from solution was found to be constituted of a ca. 5:1 mixture of two gaseous protomers, that is, the N-protonated (1a) and ring protonated (1b) molecules, respectively. When dissociated, 1a nearly exclusively loses NH3, whereas 1b displays a much diverse set of fragments. When formed via CID, varying populations of 1a and 1b were detected. Two co-existing protomers of two isomeric porphyrins were also separated and characterized via post-TWIM CID. A deprotonated porphyrin sampled from a basic methanolic solution was found to be constituted predominantly of the protomer arising from deprotonation at the carboxyl group, which dissociates promptly by CO2 loss, but a CID-resistant protomer arising from deprotonation at a porphyrinic ring NH was also detected and characterized. The doubly deprotonated porphyrin was found to be constituted predominantly of a single protomer arising from deprotonation of two carboxyl groups. Copyright (C) 2012 John Wiley & Sons, Ltd.

Estudo por espectrometria de massas de soluções de hidróxi(tosilóxi)iodobenzeno: propostas para mecanismos de desproporção

Solutions of [hydroxy(tosyloxy)iodo]benzene (HTIB or Koser's reagent) in acetonitrile were analyzed using high resolution electrospray ionization mass spectrometry (ESI-MS) and electrospray ionization tandem mass spectrometry (ESI-MS/MS) under different conditions. Several species were characterized in these analyses. Based on these data, mechanisms were proposed for the disproportionation of the iodine(III) compounds in iodine(V) and iodine(I) species.