Giovana A. Bataglion

Determination of the phenolic composition from Brazilian tropical fruits by UHPLC–MS/MS

Although Brazil is the third largest fruit producer in the world, several specimens consumed are not well studied from the chemical viewpoint, especially for quantitative analysis. For this reason and the crescent employment of mass spectrometry (MS) techniques in food science we selected twenty-two phenolic compounds with important biological activities and developed an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method using electrospray (ESI) in negative ion mode aiming their quantification in largely consumed Brazilian fruits (açaí-do-Amazonas, acerola, cashew apple, camu-camu, pineapple and taperebá). Multiple reaction monitoring (MRM) was applied and the selection of proper product ions for each transition assured high selectivity. Linearity (0.995<r(2)<0.999), limit of detection (28.85-333.3 pg/mL), limit of quantification (96.15-1111 pg/mL), inter- and intraday accuracy (>80%), precision (CV<20%) and extraction recovery rate (>80%) were satisfactory and showed that the method provides an efficient protocol to analyze phenolic compounds in fruit pulp extracts.

Comprehensive characterization of lipids from Amazonian vegetable oils by mass spectrometry techniques

An integrative approach in mass spectrometry (MS) comprising gas chromatography coupled to MS (GC-MS), ultra-efficiency liquid chromatography coupled to MS (UPLC-MS) and easy ambient sonic-spray ionization MS (EASI-MS) is proposed for the comprehensive characterization of Amazonian oils. Coconut, andiroba and castor seed oils, which are vastly sold in markets of the Amazonian region of Brazil, were selected as a representative test set. These oils were found to contain several lipids such as triacylglycerides (TAGs), fatty acids (FAs), phytosterols and limonoids. In the analyzed samples 30 different TAGs, 11 FAs, 6 phytosterols and 7 limonoids were identified. The antioxidant capacity (AOC) of the oils, as measured by their oxygen radical absorbance capacity (ORAC), was also used to evaluate their potential biological properties as well as their possible consumption as food. Edible virgin coconut oil was the most active (0.720±0.001 Trolox eq./mmol), whereas considerable lower activity was observed for andiroba and castor seed oils. The antimicrobial activities of the oils were also recorded against a panel of pathogenic bacteria and fungi in which andiroba oil was the only one that was active, solely against Enterococcus aeruginosa.

Purple carrot extract protects against cadmium intoxication in multiple organs of rats: Genotoxicity, oxidative stress and tissue morphology analyses

The aim of this study was to investigate if purple carrot extract is able to protect against the noxious activities induced by cadmium exposure in multiple organs of rats. For this purpose, histopathological analysis, genotoxicity and oxidative status were investigated in this setting. A total of twenty Wistar rats weighing 250g on the average, and 8 weeks age were distributed into four groups (n=5), as follows: Control group (non-treated group, CTRL); Cadmium group (Cd) and Purple carrot extract groups at 400mg/L or 800mg/L. Histopathological analysis revealed that liver from animals treated with purple carrot extract improved tissue degeneration induced by cadmium intoxication. Genetic damage was reduced in blood and hepatocytes as depicted by comet and micronucleus assays in animals treated with purple carrot extract. SOD-CuZn and cytocrome C gene expression increased in groups treated with purple carrot extract. Purple carrot extract also reduced the 8OHdG levels in liver cells when compared to cadmium group. Taken together, our results demonstrate that purple carrot extract is able to protect against cadmium intoxication by means of reducing tissue regeneration, genotoxicity and oxidative stress in multiple organs of Wistar rats.

Jabuticaba (Myrciaria cauliflora) Seeds: Chemical Characterization and Extraction of Antioxidant and Antimicrobial Compounds.

This study was aimed to assess the effect of time and temperature on the extraction of antioxidant compounds from jabuticaba seeds (Myrciaria cauliflora cv. Sabará), to optimize the solvent proportion (water, ethyl alcohol, and propanone), and to characterize the extract according to the chemical composition, antioxidant, and antimicrobial properties. Proximal composition, total phenolic content (TPC), antioxidant, and antimicrobial activities were analyzed. The optimized solvent ratio of 60% water and 40% propanone provided a mean TPC of 8.65 g GAE/100 g seeds and the antioxidant activity toward 2,2-diphenyl-1-picrylhydrazyl (DPPH) was 82.79% ± 0.50%. Time and temperature parameters did not influence the yield of TPC. The gross seed extract was partially purified and both exhibited a high antioxidant activity and antimicrobial potential toward Gram-positive and Gram-negative bacteria. The purified jabuticaba seed lyophilized extract contained a higher (P < 0.05) TPC, o-diphenols, flavonols, and antioxidant activity measured by the DPPH assay and total reducing capacity as compared to the gross lyophilized extract. Electrospray ionization coupled with tandem mass spectrometry (ESI-MS/MS) data showed the presence of ellagitannins and ellagic acid in the extracts, which are probably the responsible for the antimicrobial and antioxidant activities.

Adsorption in a Fixed-Bed Column and Stability of the Antibiotic Oxytetracycline Supported on Zn(II)-[2-Methylimidazolate] Frameworks in Aqueous Media

A metal-organic framework, Zn-[2-methylimidazolate] frameworks (ZIF-8), was used as adsorbent material to remove different concentrations of oxytetracycline (OTC) antibiotic in a fixed-bed column. The OTC was studied at concentrations of 10, 25 and 40 mg L-1. At 40 mg L-1, the breakthrough point was reached after approximately 10 minutes, while at 10 and 25 mg L-1 this point was reached in about 30 minutes. The highest removal rate of 60% for the 10 mg L-1 concentration was reached after 200 minutes. The highest adsorption capacity (28.3 mg g-1) was attained for 25 mg L-1 of OTC. After the adsorption process, a band shift was observed in the UV-Vis spectrum of the eluate. Additional studies were carried out to determine the cause of this band shift, involving a mass spectrometry (MS) analysis of the supernatant liquid during the process. This investigation revealed that the main route of adsorption consisted of the coordination of OTC with the metallic zinc centers of ZIF-8. The materials were characterized by thermal analysis (TA), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and infrared spectroscopy (IR) before and after adsorption, confirming the presence of OTC in the ZIF-8 and the latter’s structural stability after the adsorption process.

Separation of glycosidic catiomers by TWIM-MS using CO2 as a drift gas

Traveling wave ion mobility mass spectrometry (TWIM-MS) is shown to be able to separate and characterize several isomeric forms of diterpene glycosides stevioside (Stv) and rebaudioside A (RebA) that are cationized by Na(+) and K(+) at different sites. Determination and characterization of these coexisting isomeric species, herein termed catiomers, arising from cationization at different and highly competitive coordinating sites, is particularly challenging for glycosides. To achieve this goal, the advantage of using CO2 as a more massive and polarizable drift gas, over N2, was demonstrated. Post-TWIM-MS/MS experiments were used to confirm the separation. Optimization of the possible geometries and cross-sectional calculations for mobility peak assignments were also performed.

Determination of Geochemically Important Sterols and Triterpenols in Sediments Using Ultrahigh-Performance Liquid Chromatography Tandem Mass Spectrometry (UHPLC–MS/MS)

A fast, sensitive, and selective ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method that is able to quantify geochemical biomarkers in sediment is described. A pool of 10 sterols, which can be used as biomarkers of autochthonous (cholesterol, cholestanol, brassicasterol, ergosterol), allochthonous (stigmasterol, β-sitosterol, campesterol, and stigmastanol) and anthropogenic (coprostanol and epicoprostanol) organic matter (OM), and three triterpenols (lupeol, α-amyrin, and β-amyrin) were chosen as the analytes. The method showed excellent analytical parameters, and, compared with the traditional GC-MS methods that are commonly applied for the analysis of sterols, this method requires no sample cleanup or derivatization and presents improved values for the LOD and LOQ. UHPLC can separate the diastereoisomers (epicoprostanol, coprostanol, and cholestanol) and the isomers (lupeol, α-amyrin, and β-amyrin). The method was successfully applied for the quantification of the biomarkers, and thus, it was applied to assess the OM sources and the impacts of anthropogenic activities in sediments from different environments, such as Antarctica and other Brazilian systems (Continental Shelf, São Sebastião Channel, and Santos Estuary). Unique profiles of the biomarkers were observed for the contrasting environments, and β-amyrin and cholesterol were more predominant in the Santos Estuary and Antarctica samples, respectively. The sterol ratios indicated a higher level of sewage contamination in the Santos Estuary.

Assessment of anthropogenic contamination with sterol markers in surface sediments of a tropical estuary (Itajaí-Açu, Brazil).

The Itajaí-Açu estuarine region is one of the most important estuarine systems of south Brazil, due to the location of the Itajaí Harbor, which is the major route of international trading of the state and the largest national fishing pole landing. In addition, industries as well as urban and tourism activities are potential sources of pollution in this area. In the present study, sediment samples from 12 stations along the estuarine system were collected and extracted followed by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis. Eight sterols were identified and quantified, indicating natural and anthropogenic sources. Coprostanol concentrations ranged from <4 up to 8930 ng g(-1) of dry weight sediment with higher values being observed in the area next to the Itajaí Harbor and under influence of Itajaí-Mirim River flow, which receives wastewater from several cities. Concentrations and selected sterol ratios were useful tools used to distinguish anthropogenic and biogenic organic matter (OM) sources in the studied area, where coprostanol concentrations higher than 500 ng g(-1) were observed in 42% of the stations analyzed, indicating strong sewage contamination. Factor analysis with principal component analysis (FA/PCA) has distinguished two different groups of samples, with high and low total sterol concentrations. FA/PCA results revealed that the stations located in the estuary were separated by PC1 because they are clearly contaminated by sewage, also pointed by coprostanol/(coprostanol+cholestanol) and coprostanol/cholesterol ratios and by the higher concentrations of fecal sterols.

Synthesis of 2-arylbenzimidazoles under mild conditions catalyzed by a heteropolyacid-containing task-specific ionic liquid and catalyst investigation by electrospray (tandem) mass spectrometry

A task-specific ionic liquid constituted by a Bronsted acid (1-(3-sulfopropyl)-3-methyl-imidazolium hydrogen sulfate) as the cation, namely MSI, and by [PW12O40]3− as the triply charged counter-anion, namely PW (a heteropolyacid derivative), was used as an efficient catalyst for the condensation reaction between aldehydes and o-phenylenediamines.

Insights on the Petasis Borono–Mannich multicomponent reaction mechanism

A joint experimental and theoretical investigation on the mechanism of the Petasis Borono–Mannich reaction is described. Using the charge-tag strategy for mass spectrometry ion monitoring in solution, unprecedented key intermediates were intercepted and characterized. A key intermediate was also isolated from the reaction solution and its structure could be deduced from single crystal X-ray diffraction. A mechanism further consolidated by DFT calculations that reconciles the present and all available data on this important multicomponent reaction is presented.