Gas chromatographic analysis of indole alkaloids from Tabernaemontana hilariana

A fast and efficient procedure was elaborated to identify the alkaloid constituents from Tabernaemontana hilariana (Apocynaceae). The strategy based on fractioning of the crude alkaloid fraction in small silica cartridges followed by thin-layer chromatography (TLC), capillary gas chromatography-flame ionization detection as well as high-resolution gas chromatography-mass spectrometry afforded voacangine, coronaridine, ibogamine, voacangine pseudoindoxyl, voacangine hydroxyindolenine, 3-hydroxycoronaridine and 3-(2-oxopropyl)coronaridine. (C) 1997 Elsevier B.V. B.V.

Screening Brazilian C gasoline quality: Application of the SIMCA chemometric method to gas chromatographic data

A total of 2400 samples of commercial Brazilian C gasoline were collected over a 6-month period from different gas stations in the São Paulo state, Brazil, and analysed with respect to 12 physicochemical parameters according to regulation 309 of the Brazilian Government Petroleum, Natural Gas and Biofuels Agency (ANP). The percentages (v/v) of hydrocarbons (olefins, aromatics and saturated) were also determined. Hierarchical cluster analysis (HCA) was employed to select 150 representative samples that exhibited least similarity on the basis of their physicochemical parameters and hydrocarbon compositions. The chromatographic profiles of the selected samples were measured by gas chromatography with flame ionisation detection and analysed using soft independent modelling of class analogy (SIMCA) method in order to create a classification scheme to identify conform gasolines according to ANP 309 regulation. Following the optimisation of the SIMCA algorithm, it was possible to classify correctly 96% of the commercial gasoline samples present in the training set of 100. In order to check the quality of the model, an external group of 50 gasoline samples (the prediction set) were analysed and the developed SIMCA model classified 94% of these correctly. The developed chemometric method is recommended for screening commercial gasoline quality and detection of potential adulteration. (c) 2007 Elsevier B.V. All rights reserved.

Gas Chromatographic Determination of Cyprodinil, Fludioxonil, Pyrimethanil, and Tebuconazole in Grapes, Must, and Wine

A rapid and simple gas chromatographic method for determinating cyprodinil, fludioxonil, pyrimethanil, and tebuconazole in grapes, must, and wine is described. An on-line microextraction method was used with a one-step extraction-partition procedure. Nitrogen-phosphorus and mass spectrometric detectors were used, because of their low sensitivity and high selectivity. Because of high selectivity of detector, no cleanup was necessary and the extract was concentrated 5 times. Recoveries from fortified grapes, must, and wine ranged from 93 to 110%. Limits of determination were 0.05 mg/kg for cyprodinil and pyrimethanil and 0.10 mg/kg for fludioxonil and tebuconazole.

A simple and rapid extraction for gas chromatographic determination of thiabendazole and imazalil residues in lemons

A rapid and efficient method is described for the determination of thiabendazole and imazalil residues in lemons (peel and pulp). The procedure is based on the extraction with an hexane:ethyl acetate mixture (1:1, v/v) and gas chromatographic analysis using thermionic specific detection (TSD). The possibility of matrix effect was also studied. Mean recoveries from 8 replicates of fortified samples ranged from 79% to 109%, with relative standard deviation values between 2.4% to 12.8%. The detection and quantification limits of the method were 0.2 mg kg-1 and 0.5 mg kg-1, respectively.

Isolamento e seleção de leveduras fermentadoras de xilose

Pós-graduação em Microbiologia - IBILCE

Potencialização de óleos essenciais como antimicrobianos aplicados em produtos lácteos fermentados

Pós-graduação em Biologia Geral e Aplicada - IBB

Solarização em microcosmo: efeito de materiais vegetais na sobrevivência de fitopatógenos e na produção de voláteis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bioconversion of Cellulose to Hydrogen by dark fermentation

Hydrogen is known as a clean energy resource. The biological production of hydrogen has been attracting attention as an environmentally friendly processs that does not consume fossil fuels. Cellulosic plant and waste materials are potential resources for fermentative hydrogen production. Cellulose is a linear biopolymer of glucose molecules, connected by β-1,4-glycosidic bonds. Enzymatic hydrolysis of cellulose requires the presence of cellulase. The present study aimed to investigate the efficiency of acid pretreatment on ruminal fluid in order to enrich H2 producing bacteria consortia to enhance biohydrogen rate and substrate removal efficiency. In this study, fermentative hydrogen producers were enriched on cellulose (2g/L) in a modificated Del Nery medium (DNM) at 37ºC and initial pH 7.0 using rumen fluid (10% v/v) as inoculum. To increase the hydrogen production it was added cellulose (10mL) to the medium. The gas products (mainly H2 and CO2) was analyzed by gas chromatography (Shimadzu GC 2010) using a thermal conductivity detector. The volatile fatty acids and ethanol were also detected by GC using a flame ionization detector. Cellulose degradation was quantified by using the phenolsulfuric acid method. Analysis showed that the biogas produced from the anaerobic fermentation contained only hydrogen and carbon dioxide, without detectable methane after acid pretreatment test. On DNM the hydrogen production started with 4 h (5,3 x 105 mmol H2/L) of incubation, and the maximum H2 concentration was observed with 34 h (7,1 x 106 mmol H2/L) of incubation. During the process, it was observed a predominance of acetic acid and butyric acid as well as a low production of acetone, ethanol and nbutanol in all experimental phases. Butyrate accounted for more than 77% of total. As a result of the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system was reduced to 4,0. On microscopy analyses there were observed rods with endospores. The batch anaerobic fermentation assays performed on anaerobic mixed inoculum from rumen fluid demonstrated the feasibility of H2 generation utilizing cellulose as substrate. Based on the results, it can be concluded that the acid treatment was efficient to inhibit the methanogenic archaea cells present in rumen fluid. The rumen fluid cells present a potential route in converting renewable biomass such as cellulose into hydrogen energy.

Assessment of antimicrobial activity of cinnamon (Cinnamomum zeylanicum) essential oil combined with EDTA and polyethylene glycol in yogurt

Essential oils (EOs) are technological options that may be employed in natural foods due to their antimicrobial activities. However, restrictions exist when high EOs concentrations are required which, in their turn, affect sensory qualities. Technological alternatives, such as combination of EOs with chelating and dispersing agents, have been proposed in the literature. Current research determined the antimicrobial activity of cinnamon EO against microbial spoilage in yogurt when added at the highest acceptable sensory EO concentration, alone or associated with ethylenediaminetetraacetic acid (EDTA) and/or polyethylene glycol. Cinnamon EO's chemical analysis was performed by gas chromatography-mass spectrometry (GC-MS). Sensory analysis was conducted to define the highest acceptable sensory concentration of cinnamon EO in yogurt, stipulated at 0.04% cinnamon EO. Antimicrobial activity in yogurt was then evaluated for aerobic mesophiles, psychrotrophilic microorganisms, yeasts and molds counts. Treatments comprised (1) control, (2) 0.04% EO, (3) 0.04% EO + 0.01% EDTA, (4) 0.04% EO + 0.02% polyethylene glycol; (5) 0.04% EO + 0.01% EDTA + 0.2% polyethylene glycol, in triplicates. Concentration 0.04% of cinnamon EO, alone or associated with EDTA and/or polyethylene glycol, failed to show any antimicrobial activity against aerobic mesophiles, yeasts and molds.

In vitro efficacy of the essential oil of Piper cubeba L. (Piperaceae) against Schistosoma mansoni

In this paper, cercariae, schistosomula, and adult Schistosoma mansoni worms were incubated in vitro with the essential oil of Piper cubeba (PC-EO) at concentrations from 12.5 to 200 mu g/mL, and the viability was evaluated using an inverted microscopy. The effects of PC-EO at 100 and 200 mu g/mL on the stages of S. mansoni were similar to those of the positive control (PZQ at 12.5 mu g/mL), with total absence of mobility after 120 h. However, at concentrations from 12.5 to 50 mu g/mL, PC-EO caused a reduction in the viability of cercariae and schistosomula when compared with the negative control groups (RPMI 1640 or dechlorinated water) or (RPMI 1640 + 0.1% DMSO or dechlorinated water + 0.1% DMSO). On the other hand, adult S. mansoni worms remained normally active when incubated with PC-EO at concentrations of 12.5 and 25 mu g/mL, and their viabilities were similar to those of the negative control groups. In addition, at concentrations ranging from 50 to 200 mu g/mL, separation of all the coupled adult worms was observed after 24 h of incubation, which is related to the fact of the reduction in egg production at this concentration. The main chemical constituents of PC-EO were identified by gas chromatography-mass spectrometry as being sabinene (19.99%), eucalyptol (11.87%), 4-terpineol (6.36%), beta-pinene (5.81%), camphor (5.61%), and delta-3-carene (5.34%). The cytotoxicity of the PC-EO was determined, and a significant cytotoxicity was only obtained in the concentration of 200 mu g/mL after 24 h treatment. The results suggest that PC-EO possesses an effect against cercariae, schistosomula, and adult worms of the S. mansoni.

Advanced Glycation in macrophages induces intracellular accumulation of 7-ketocholesterol and total sterols by decreasing the expression of ABCA-1 and ABCG-1

Abstract Background Advanced glycation end products (AGE) alter lipid metabolism and reduce the macrophage expression of ABCA-1 and ABCG-1 which impairs the reverse cholesterol transport, a system that drives cholesterol from arterial wall macrophages to the liver, allowing its excretion into the bile and feces. Oxysterols favors lipid homeostasis in macrophages and drive the reverse cholesterol transport, although the accumulation of 7-ketocholesterol, 7alpha- hydroxycholesterol and 7beta- hydroxycholesterol is related to atherogenesis and cell death. We evaluated the effect of glycolaldehyde treatment (GAD; oxoaldehyde that induces a fast formation of intracellular AGE) in macrophages overloaded with oxidized LDL and incubated with HDL alone or HDL plus LXR agonist (T0901317) in: 1) the intracellular content of oxysterols and total sterols and 2) the contents of ABCA-1 and ABCG-1. Methods Total cholesterol and oxysterol subspecies were determined by gas chromatography/mass spectrometry and HDL receptors content by immunoblot. Results In control macrophages (C), incubation with HDL or HDL + T0901317 reduced the intracellular content of total sterols (total cholesterol + oxysterols), cholesterol and 7-ketocholesterol, which was not observed in GAD macrophages. In all experimental conditions no changes were found in the intracellular content of other oxysterol subspecies comparing C and GAD macrophages. GAD macrophages presented a 45% reduction in ABCA-1 protein level as compared to C cells, even after the addition of HDL or HDL + T0901317. The content of ABCG-1 was 36.6% reduced in GAD macrophages in the presence of HDL as compared to C macrophages. Conclusion In macrophages overloaded with oxidized LDL, glycolaldehyde treatment reduces the HDL-mediated cholesterol and 7-ketocholesterol efflux which is ascribed to the reduction in ABCA-1 and ABCG-1 protein level. This may contribute to atherosclerosis in diabetes mellitus.

Tissue metabolomics of hepatocellular carcinoma: Tumor energy metabolism and the role of transcriptomic classification

Hepatocellular carcinoma (HCC) is one of the commonest causes of death from cancer. A plethora of metabolomic investigations of HCC have yielded molecules in biofluids that are both up- and down-regulated but no real consensus has emerged regarding exploitable biomarkers for early detection of HCC. We report here a different approach, a combined transcriptomics and metabolomics study of energy metabolism in HCC. A panel of 31 pairs of HCC tumors and corresponding nontumor liver tissues from the same patients was investigated by gas chromatography-mass spectrometry (GCMS)-based metabolomics. HCC was characterized by ∼2-fold depletion of glucose, glycerol 3- and 2-phosphate, malate, alanine, myo-inositol, and linoleic acid. Data are consistent with a metabolic remodeling involving a 4-fold increase in glycolysis over mitochondrial oxidative phosphorylation. A second panel of 59 HCC that had been typed by transcriptomics and classified in G1 to G6 subgroups was also subjected to GCMS tissue metabolomics. No differences in glucose, lactate, alanine, glycerol 3-phosphate, malate, myo-inositol, or stearic acid tissue concentrations were found, suggesting that the Wnt/β-catenin pathway activated by CTNNB1 mutation in subgroups G5 and G6 did not exhibit specific metabolic remodeling. However, subgroup G1 had markedly reduced tissue concentrations of 1-stearoylglycerol, 1-palmitoylglycerol, and palmitic acid, suggesting that the high serum α-fetoprotein phenotype of G1, associated with the known overexpression of lipid catabolic enzymes, could be detected through metabolomics as increased lipid catabolism. Conclusion: Tissue metabolomics yielded precise biochemical information regarding HCC tumor metabolic remodeling from mitochondrial oxidation to aerobic glycolysis and the impact of molecular subtypes on this process.

Stability of 3-bromotyrosine in serum and serum 3-bromotyrosine concentrations in dogs with gastrointestinal diseases

Abstract BACKGROUND: 3-Bromotyrosine (3-BrY) is a stable product of eosinophil peroxidase and may serve as a marker of eosinophil activation. A gas chromatography/mass spectrometry method to measure 3-BrY concentrations in serum from dogs has recently been established and analytically validated. The aims of this study were to determine the stability of 3-BrY in serum, to determine the association between peripheral eosinophil counts and the presence of an eosinophilic infiltrate in the gastrointestinal tract, and to compare serum 3-BrY concentrations in healthy dogs (n = 52) and dogs with eosinophilic gastroenteritis (EGE; n = 27), lymphocytic-plasmacytic enteritis (LPE; n = 25), exocrine pancreatic insufficiency (EPI; n = 26), or pancreatitis (n = 27). RESULTS: Serum 3-BrY concentrations were stable for up to 8, 30, and 180 days at 4°C, -20°C, and -80°C, respectively. There was no significant association between peripheral eosinophil count and the presence of eosinophils in the GI tissues (P = 0.1733). Serum 3-BrY concentrations were significantly higher in dogs with EGE (median [range] = 5.04 [≤0.63-26.26] μmol/L), LPE (median [range] = 3.60 [≤0.63-15.67] μmol/L), and pancreatitis (median [range] = 1.49 [≤0.63-4.46] μmol/L) than in healthy control dogs (median [range] = ≤0.63 [≤0.63-1.79] μmol/L; P < 0.0001), whereas concentrations in dogs with EPI (median [range] = 0.73 [≤0.63-4.59] μmol/L) were not different compared to healthy control dogs. CONCLUSIONS: The present study revealed that 3-BrY concentrations were stable in serum when refrigerated and frozen. No relationship between peripheral eosinophil count and the presence of eosinophils infiltration in the GI tissues was found in this study. In addition, serum 3-BrY concentrations were increased in dogs with EGE, but also in dogs with LPE and pancreatitis. Further studies are needed to determine whether measurement of 3-BrY concentrations in serum may be useful to assess patients with suspected or confirmed EGE or LPE.