Characteristic product ions of acetylene carotenoids by electrospray and nanospray ionization tandem mass spectrometry

[No abstract

EFFECT OF CHARGE GENERATION IN ESI SOURCE ON THE NEUTRAL AROMATIC ELIMINATION MECHANISM IN XANTHOPHYLLS

Carotenes and xanthophylls are natural pigments with high economic relevance in chemical, cosmetics, food and pharmaceutical industries. Systematic studies of carotenoid fragmentation pathways have demonstrated that the neutral elimination of aromatic ring from the polyene chain by electrocyclization reaction produced diagnostic ions to rapidly identify their presence in mixture. However, carotenes and xanthophylls also showed the ability to produce both protonated and radical molecular species, opening up multiple acid-base and/or redox fragmentation, which hamper carotenoids elucidation. Here we investigate the ionization and fragmentation of the radical/protonated and sodiated parent masses [M]+•/[M+H]+ and [M+Na]+ of two natural xanthophylls (canthaxanthin and fucoxanthin) and the synthetic apo-b-carotene using a Fourier-transform ion-cyclotron resonance mass spectrometer (FTICR MS). The MS/MS analysis showed that sodium adduct yielded better fragmentation of the diagnostic aromatic ring elimination in a simpler MS/MS spectra, whereas molecular ion and protonated molecule resulted in a multitude of fragments involving additional charge-remote fragmentations and direct cleavages of the conjugated π-system by retro-ene and vinyl-allyl reactions. The results suggested that Na+ promoted electrocyclic aromatic ring elimination by assisting the correct orbital conformation of the polyene chain, giving clearly fragments to the unambiguous determination of carotenoids in biological samples.     Keywords: carotenoids, xanthophylls, pericyclic rearrangement, electrocyclization, aromatic ring elimination, FTICR M

Metabolomics method to comprehensively analyze amino acids in different domains

Amino acids play essential roles in both metabolism and the proteome. Many studies have profiled free amino acids (FAAs) or proteins; however, few have connected the measurement of FAA with individual amino acids in the proteome. In this study, we developed a metabolomics method to comprehensively analyze amino acids in different domains, using two examples of different sample types and disease models. We first examined the responses of FAAs and insoluble-proteome amino acids (IPAAs) to the Myc oncogene in Tet21N human neuroblastoma cells. The metabolic and proteomic amino acid profiles were quite different, even under the same Myc condition, and their combination provided a better understanding of the biological status. In addition, amino acids were measured in 3 domains (FAAs, free and soluble-proteome amino acids (FSPAAs), and IPAAs) to study changes in serum amino acid profiles related to colon cancer. A penalized logistic regression model based on the amino acids from the three domains had better sensitivity and specificity than that from each individual domain. To the best of our knowledge, this is the first study to perform a combined analysis of amino acids in different domains, and indicates the useful biological information available from a metabolomics analysis of the protein pellet. This study lays the foundation for further quantitative tracking of the distribution of amino acids in different domains, with opportunities for better diagnosis and mechanistic studies of various diseases

Mitochondrial Inorganic Polyphosphate (polyP) Is a Potent Regulator of Mammalian Bioenergetics in SH-SY5Y Cells: A Proteomics and Metabolomics Study

Inorganic polyphosphate (polyP) is an ancient, ubiquitous, and well-conserved polymer which is present in all the studied organisms. It is formed by individual subunits of orthophosphate which are linked by structurally similar bonds and isoenergetic to those found in ATP. While the metabolism and the physiological roles of polyP have already been described in some organisms, including bacteria and yeast, the exact role of this polymer in mammalian physiology still remains poorly understood. In these organisms, polyP shows a co-localization with mitochondria, and its role as a key regulator of the stress responses, including the maintenance of appropriate bioenergetics, has already been demonstrated by our group and others. Here, using Wild-type (Wt) and MitoPPX (cells enzymatically depleted of mitochondrial polyP) SH-SY5Y cells, we have conducted a comprehensive study of the status of cellular physiology, using proteomics and metabolomics approaches. Our results suggest a clear dysregulation of mitochondrial physiology, especially of bioenergetics, in MitoPPX cells when compared with Wt cells. Moreover, the effects induced by the enzymatic depletion of polyP are similar to those present in the mitochondrial dysfunction that is observed in neurodegenerative disorders and in neuronal aging. Based on our findings, the metabolism of mitochondrial polyP could be a valid and innovative pharmacological target in these conditions.</jats:p

The Natural Products Atlas : an open access knowledge base for microbial natural products discovery

Despite rapid evolution in the area of microbial natural products chemistry, there is currently no open access database containing all microbially produced natural product structures. Lack of availability of these data is preventing the implementation of new technologies in natural products science. Specifically, development of new computational strategies for compound characterization and identification are being hampered by the lack of a comprehensive database of known compounds against which to compare experimental data. The creation of an open access, community-maintained database of microbial natural product structures would enable the development of new technologies in natural products discovery and improve the interoperability of existing natural products data resources. However, these data are spread unevenly throughout the historical scientific literature, including both journal articles and international patents. These documents have no standard format, are often not digitized as machine readable text, and are not publicly available. Further, none of these documents have associated structure files (e.g., MOL, InChI, or SMILES), instead containing images of structures. This makes extraction and formatting of relevant natural products data a formidable challenge. Using a combination of manual curation and automated data mining approaches we have created a database of microbial natural products (The Natural Products Atlas, www.npatlas.org) that includes 24 594 compounds and contains referenced data for structure, compound names, source organisms, isolation references, total syntheses, and instances of structural reassignment. This database is accompanied by an interactive web portal that permits searching by structure, substructure, and physical properties. The Web site also provides mechanisms for visualizing natural products chemical space and dashboards for displaying author and discovery timeline data. These interactive tools offer a powerful knowledge base for natural products discovery with a central interface for structure and property-based searching and presents new viewpoints on structural diversity in natural products. The Natural Products Atlas has been developed under FAIR principles (Findable, Accessible, Interoperable, and Reusable) and is integrated with other emerging natural product databases, including the Minimum Information About a Biosynthetic Gene Cluster (MIBiG) repository, and the Global Natural Products Social Molecular Networking (GNPS) platform. It is designed as a community-supported resource to provide a central repository for known natural product structures from microorganisms and is the first comprehensive, open access resource of this type. It is expected that the Natural Products Atlas will enable the development of new natural products discovery modalities and accelerate the process of structural characterization for complex natural products libraries

Elaboração de métodos analíticos de desreplicação para o estudo metabolômico em espedies de Qualea (Vochysiaceae) : detecção e elucidação in situ de micromoléculas com potencial antioxidante

Neste trabalho foi desenvolvida uma metodologia de desreplicação bioguiada para Qualea grandiflora e Q. cordata, duas espécies da família Vochysiaceae presentes no Cerrado Brasileiro com potencial etnofarmacológico, através dos bioensaios in vitro de inibição da polimerização da β-hematina bovina (compostos antimaláricos), redução do radical estável DPPH (antioxidante), bioautografia para avaliação da inibição da enzima acetilcolinesterase, avaliação citotóxica em linhagens celulares, avaliação de atividade antifúngica por microdiluição em placa e avaliação tripanocida frente à cepas Y de epimastigotas de Tripanosoma cruzi e, da detecção in silico dos constituintes moleculares majoritários a partir da técnica hifenada de HPLC-DAD-HRMS(ESI). As folhas e os ramos secos de Q.grandiflora e Q.cordata foram extraídos por maceração com etanol:água (8:2) e posteriormente fracionados em extração líquido-líquido com os solventes hexano, AcOEt e n-butanol. Entre os bioensaios realizados, a avaliação de inibição do radical DPPH apresentou valores significativos para as frações AcOEt dos ramos de Q.grandiflora e das folhas de Q. cordata. A partir disto, estas frações foram analisadas através da técnica hifenada HPLC-DAD-HRMS(ESI) e permitiram a detecção das flavanonas: 4',5,7-triidroxi-3'-metoxi-6,8-dimetilflavanona e 5,6,7-triidroxi-3',4'-dimetoxi-8-metilflavanona e dos diidroflavonóis: 4',7-diidroxi-5-metoxi-6-metildiidroflavonol e 3',4'-dimetoxi-5,7-diidroxi-6,8-dimetildiidroflavonol na fração AcOEt nas folhas de Q.cordata, e das flavanonas: 8-metilnaringenina e 4',5,7-triidroxi-3',6-dimetoxi-8-metilflavanona; benzofenona: Bis(2-hidroxi-4,6-dimetoxi-3-metilfenil)metanona e diidroflavonol: 3',4',5,6,7-pentaidroxi-8-metildiidroflavonol da fração AcOEt dos ramos de Q.grandiflora. Também realizou-se a análise in silico por RMN da fração...In this work the bioguided phytochemical studies of Qualea grandiflora and Q. cordata, two species of Vochysiaceae greatly represented in the Brazilian Cerrado and with ethnopharmacology potential, were perfomed according to in vitro bioassays from antioxidant capacity and inhibition of ß-hematin polymerization (antimalarial compounds), scavenging activity of DPPH (antioxidant capacity), inhibition of acetyl cholinesterase (anti-Alzheimer), citotoxic activity against tumoral cell lines (anticancer), antifungal activity using a microdilution assay and tripanocidal activity performed with the Y-strain epimastigote forms of Tripanosoma cruzi, as well as in silico dereplication by means of HPLC-DAD-HRMS(ESI). The leaves and stem of Q.grandiflora and Q.cordata were extracted by maceration in etanol:water (8:2) and fractionated by liquid-liquid using hexane, AcOEt and n-butanol. The bioassays showed that AcOEt stem fraction of Q.grandiflora and AcOEt leaves fraction of Q. cordata are significantly activity in DPPH reduction. According to this results, the AcOEt fraction of the stem of Q.grandiflora and the leaves of Q.cordata were evaluated using HPLC-DAD-HRMS(ESI) and allowed the detection of two flavanones: 4',5,7-trihydroxy-3-methoxy-6,8-dimethylflavanone and 5,6,7-trihydroxy-3',4'-dimethoxy-8-methylflavanone, and the dihydroflavonols: 4',7-dihydroxy-5-methoxy-6-methyldihydroflavonol and 3',4'-dimethoxy-5,7-dihydroxy-6,8-dimethyldihydroflavonol from AcOEt leaves fraction of Q.cordata, and the flavanones: 8-methyl-naringenine and 4',5,7-trihydroxy-3',6-dimethoxy-8-methylflavanone, the benzophenone: bis (2-hydroxy-4,6-dimethoxy-3-methylphenyl) metanone, and the dihydroflavonol: 3',4',5,6,7-pentahydroxy-8-methyldihydroflavonol from AcOEt stem fraction of Q. grandiflora. The AcOEt stem fraction of Q. grandiflora was analyzed through in silico NMR, comparing virtual 1H NMR standards spectra... (Complete abstract click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Estudo de espécies de Chrysobalanaceae com ação citotóxica: análise metabolômica visando ao entendimento de associações sinérgicas e da complexidade micromolecular

A abordagem reducionista na busca por substâncias bioativas em produtos naturais nem sempre é capaz de compreender em sua totalidade a dinâmica envolvida nas respostas farmacológicas de matrizes complexas como extratos vegetais. Inserido neste paradigma, este trabalho visou ao desenvolvimento de métodos e abordagens racionais que permitissem o entendimento das relações moleculares em produtos naturais bioativos. Para tanto, espécies vegetais da família Chrysobalanaceae com potencial citotóxico, depositadas na extratoteca do NuBBE, foram os objetos de estudo na aplicação de metodologias para a determinação de sua composição metabólica e para a avaliação do potencial citotóxico. Os extratos hidroalcoólicos de Couepia grandiflora, Hirtella hebeclada, Licania hoehnei, Licania kunthiana, Licania huminis e Parinari excelsa foram analisados por CG-EM, CLAE-DAD-EM/EM e CLAE-autoEM/EM para a identificação in situ de sua composição metabólica, através de comparação dos dados espectrais a uma base de dados contendo valores de massas de alta resolução e espectros de UV de todos os metabólitos secundários já relatados para a família Chrysobalanaceae. O uso de ferramentas de análise multivariada, como a deconvolução empírica proposta pelo software AMDIS e a extração espectral desenvolvidas pelos algoritmos RAMSY e MCR-ALS, assistiram à desreplicação ao extrair os espectros dos compostos, mesmo em baixa resolução cromatográfica. A desreplicação das espécies de Chrysobalanaceae permitiu a detecção in situ de metabólitos primários (aminoácidos, ácidos e açúcares) e secundários (flavonoides-O-glicosilados e polímeros de proantocianidinas). Adicionalmente ao estudo de determinação metabólica das matrizes vegetais, realizaram-se ensaios de atividade citotóxica. Resultados preliminares da bioatividade ante diferentes linhagens de Saccharomyces cereviceae, obtidos...The reductionist approach for the search of bioactive compounds in natural products is not always being able to understand the complete dynamics involved in the pharmacological responses of complex matrices such as plant extracts. Based on this paradigm, this study aimed to develop rational methods approaches to runderstand the molecular relationships present in bioactive natural products. Chrysobalanaceae plant species with cytotoxic potential, deposited NuBBE`s bank of extracts, were the objects of study in the application of methodologies for defining the metabolic composition and evaluate their cytotoxic potential. Couepia grandiflora, Hirtella hebeclada, Licania hoehnei, Licania kunthiana, Licania huminis and Parinari excelsa ethanol extracts were analyzed by GC-MS, HPLC-DAD-MS/MS and HPLC-autoMS/MS for in situ metabolic identification based on spectral comparison with a high resolution mass spectra and UV spectral database developed using previously reported data for Chrysobalanaceae. The use of multivariate analysis tools, the empirical deconvolution software AMDIS and the spectral extraction algorithms RAMSY and MCR-ALS assisted the dereplication by extracting spectral data for pure compounds even at low chromatographic resolution. The dereplication of Chrysobalanaceae species allowed the in situ detection of primary metabolites (amino acids, and sugars) and secondary (O-glycosylated-flavonoids and proanthocyanidins polymers). In addition to the metabolic determination of Chrysobalanaceae extracts, were performed cytotoxicity bioassays. Preliminary results of cytotoxicity against Saccharomyces cereviceae, carried out during the construction of the bank of extracts, indicated cytotoxic potential, especially for Hirtella hebeclada and Parinari excelsa. However, the cytotoxic assay against different tumor cell lines showed that the extracts were not active, which may be related to which may be..