Metabolomics Analyses to Investigate the Role of Diet and Physical Training.

The metabolic and physiologic responses to healthy dietary habits and physical exercise have become an increasingly interesting research area, since equilibrated diet and regular physical activity are commonly recommended for their antioxidant capacity and for the prevention and treatment of several disorders as insulin resistance, dyslipidemia, obesity, and hypertension that may result in cardiovascular disease and type II diabetes.Nutritional and exercise-induced responses and the biological mechanisms that explain these associations have been tackled by several researchers using metabolomic approaches that have emerged as a powerful tool to comprehensively evaluate individual metabolic signatures, analyzing metabolome composition in serum, urine, stool, or tissue samples.The overview of the wide range of metabolites related to dietary and to physical training interventions reported from numerous human or animal studies endorses the complexity for assessing metabolic changes and compound identification, and a combination of targeted and non-targeted global profiling studies is recommended for increasing the understanding of nutrition and exercise metabolic mechanisms.The present protocol attempt to identify variations in human blood circulating metabolites with a multiplatform global analysis based on LC-MS, GC-MS, and NMR, combining targeted and untargeted strategies, to complete the holistic understanding of the serum metabolome.

Analytical methods in sphingolipidomics: Quantitative and profiling approaches in food analysis.

In recent years, sphingolipidomics has emerged as an interesting omic science that encompasses the study of the full sphingolipidome characterization, content, structure and activity in cells, tissues or organisms. Like other omics, it has the potential to impact biomarker discovery, drug development and systems biology knowledge. Concretely, dietary food sphingolipids have gained considerable importance due to their extensively reported bioactivity. Because of the complexity of this lipid family and their diversity among foods, powerful analytical methodologies are needed for their study. The analytical tools developed in the past have been improved with the enormous advances made in recent years in mass spectrometry (MS) and chromatography, which allow the convenient and sensitive identification and quantitation of sphingolipid classes and form the basis of current sphingolipidomics methodologies. In addition, novel hyphenated nuclear magnetic resonance (NMR) strategies, new ionization strategies, and MS imaging are outlined as promising technologies to shape the future of sphingolipid analyses. This review traces the analytical methods of sphingolipidomics in food analysis concerning sample extraction, chromatographic separation, the identification and quantification of sphingolipids by MS and their structural elucidation by NMR.

Distribution of grape seed flavanols and their metabolites in pregnant rats and their fetuses.

SCOPE: Polyphenols have been demonstrated to provide health benefits affecting cellular and physiological processes. This study aims to evaluate the bioavailability and distribution of grape seed flavanol compounds during pregnancy and whether fetuses could be exposed to these compounds. METHODS AND RESULTS: The distribution of flavanols and their metabolites in rat plasma, liver, white adipose tissue, brain, amniotic fluid, placenta, and fetuses after 1 and 2 h of an acute intake of a grape seed proanthocyanidin extract was examined by LC-ESI-TOF/MS. Flavanols and their metabolites were widely distributed in both pregnant and nonpregnant rat plasma and tissues. In liver, the conjugated forms of flavanols were less available in pregnant than nonpregnant rats. Flavanol metabolites were abundant in maternal placenta but detected at low levels in fetuses and amniotic fluid. CONCLUSION: Flavanol metabolization appears to be less active in the liver during pregnancy. Moreover, data indicated that transport across the placenta is not efficient and for flavanols and their metabolites, the placenta seems to act as a barrier. However, these compounds target the fetus and are excreted in the amniotic fluid.

Biomarkers of food intake and metabolite differences between plasma and red blood cell matrices; a human metabolomic profile approach.

Untargeted metabolomic analyses of plasma and red blood cells (RBCs) can provide complementary information on biomarkers of food consumption. To assess blood collection differences in biomarkers, fasting blood was drawn from 10 healthy individuals using sodium citrate and lithium heparin as anticoagulants. Plasma and RBCs were separated into aqueous and lipid fractions to be analyzed using 1D and 2D (1)H NMR spectroscopy. Fatty acids were analyzed using gas chromatography-mass spectrometry (GC-MS). Polyphenols were extracted from plasma and RBCs by micro-elution solid-phase extraction and analyzed by ultra performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). (1)H NMR demonstrated higher aqueous metabolites such as glucose in plasma compared to RBCs, while RBCs contained higher ADP-ATP, creatine and acetone than plasma. Lipoproteins and their subclasses were higher in plasma than in RBCs. Percentages of saturated fatty acids (SFA) 16 : 0, 17 : 0, 20 : 0, 24 : 0 and polyunsaturated fatty acids (PUFA) 22 : 6 n-3 (docosahexaenoic acid) and 20 : 4 n-6 (arachidonic acid) were higher in RBCs than in plasma (p < 0.05), while SFA 14 : 0, monounsaturated fatty acids (MUFA) 14 : 1 n-5, 16 : 1 n-7, 17 : 1 n-7 and 18 : 1 n-9 and PUFA 18 : 3 n-3, 18 : 2 n-6, 18 : 3 n-6 and 20 : 3 n-6 were higher in plasma than in RBCs (p < 0.05). Polyphenols differed in plasma from those of RBCs. Biomarker concentrations were lower in sodium citrate compared to lithium heparin plasma. In conclusion, metabolomic profiles generated by NMR spectroscopy, GC-MS and UPLC-MS/MS analyses of RBCs versus plasma show complementary information on several specific molecular biomarkers that could be applied in nutritional assessment.

Volatile organic compounds in air at urban and industrial areas in the Tarragona region by thermal desorption and gas chromatography-mass spectrometry.

Annual trends of a group of 66 volatile organic compounds (VOCs), containing 20 ozone precursors, were the aim of a sampling campaign carried out for a year in air at urban and industrial areas from Tarragona region. VOCs were determined by active collection on multisorbent tubes, followed by thermal desorption and gas chromatography-mass spectrometry. The analytical method was developed and validated, showing good levels of detection and quantification, recoveries, precision, and linearity for all the compounds in the range being studied. All the industrial and urban samples taken during the sampling campaign were similar in their qualitative composition. The most abundant compound in all urban and industrial sites was i-pentane, with concentrations between 15.2 and 202.1 microg m(-3) in urban sites and between 1.3 and 98.6 microg m(-3) in industrial sites. In urban sites, the following compounds in order of abundance were toluene, n-pentane, m,p-xylene, and o-xylene, with maximum levels of 150.6, 45.8, 42.3, and 31.7 microg m(-3), respectively. In industrial sites, the most abundant compounds depended on the sampled site.

Characterization of ozone precursor volatile organic compounds in urban atmospheres and around the petrochemical industry in the Tarragona region.

This paper reports the results of an assessment of volatile organic compound (VOCs) levels in ambient air in samples collected at urban and industrial sites in southern Catalonia, which is home to one of the most important petrochemical complexes in southern Europe. This study contains data from a total of 192 samples collected in 2007, from May to October, at six air pollution measurement stations within the area of influence of several chemical and petrochemical industrial plants. The ambient air concentrations of a group of 65 VOCs, some of them ozone precursors, were determined by active sampling into sorbent tubes, thermal desorption and gas chromatography-mass spectrometry. At the same time, several meteorological parameters were also recorded, and levels of NO, NO(2) and O(3) measured by the automatic stations, have been included in the study as well. Ambient air profiles of the different areas were studied, and the ozone formation dependent on VOCs and NO(2) levels was also analysed, taking into account the photochemical ozone creation potential (POCP) for different groups of VOCs.

Pressurised liquid extraction of polycyclic aromatic hydrocarbons from gas and particulate phases of atmospheric samples.

Pressurised liquid extraction (PLE) was applied to determine the atmospheric levels of 16 polycyclic aromatic hydrocarbons (PAHs) in the gas and particulate phases. The method involved high-volume air sampling with quartz fibre filters (QFFs) and polyurethane foam (PUF) plugs and analytes were subsequently extracted from the samples by PLE, and determined with GC-MS. We optimised the PLE conditions for the solvent, the number of cycles and extraction temperature. Recoveries were higher than 90% for most compounds. Method LODs and LOQs were between 0.001 and 0.02 ng/m(3) and between 0.01 and 0.05 ng/m(3). Air samples were taken from a site in the region of Tarragona in Catalonia, Spain, where one of the largest petrochemical complexes in southern Europe is located. The total concentration of PAHs were from 6.7 to 27.66 ng/m(3), with predominant levels of PAHs appearing in the gas phase (48-81%), and an average level of benzo[a]pyrene, the most carcinogenic PAH, of 0.86 ng/m(3).

Determination of volatile organic sulfur compounds in the air at sewage management areas by thermal desorption and gas chromatography-mass spectrometry.

The concentrations of seven volatile organic sulfur compounds (VOSCs) in air samples were determined by active collection on multisorbent tubes followed by two-stage thermal desorption and gas chromatography-mass spectrometry. The compounds studied were ethyl mercaptan (CH(3)CH(2)SH), dimethyl sulfide ((CH(3))(2)S), carbon disulfide (CS(2)), propyl mercaptan (C(3)H(8)S), butyl mercaptan (C(4)H(10)S), dimethyl disulfide ((CH(3))(2)S(2)) and 1-pentanethiol (C(5)H(12)S). Active collection on SilcoSteel multisorbent tubes enabled an air volume of 3000ml to be sampled without observing breakthrough. This study focused on an exhaustive sampling of several process steps or sections from sewage management plants. A wide range of concentrations was observed. Dimethyl sulfide, carbon disulfide and dimethyl disulfide were the most abundant compounds in all samples, the highest concentrations being 608.5microg m(-3), 658.5microg m(-3) and 857.8microg m(-3), respectively. The less appearing compound was ethyl mercaptan, which was only detected in the sludge digestion process at a maximum concentration of 14.8microg m(-3). The remaining compounds were detected and measured in about half the samples. The sections with the maximum values of VOSCs involved sludge processes such as mixing, thickening and digestion. The results were also strongly influenced by the design characteristics of the sampling point, e.g. whether the sample was taken at a confined site or in the open air.