Quantitative profiling of retinyl esters in milk from different ruminant species by using high performance liquid chromatography-diode array detection-tandem mass spectrometry.

An effective high performance liquid chromatography-diode array detection-tandem mass spectrometry (HPLC-DAD-MS/MS) analytical approach was developed for retinoid profiling in raw milk samples (cow, buffalo, ewe, and goat). The analytes were isolated by means of liquid-liquid extraction, including a "lipid freezing" step, with yields exceeding 66%. Since the positive atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) detection is not completely selective, a reliable identification has been accomplished by fully separating the analytes on a tandem C18/C30 column system under non-aqueous reversed phase (NARP) chromatography conditions.

A novel library of saccharin and acesulfame derivatives as potent and selective inhibitors of carbonic anhydrase IX and XII isoforms.

Small libraries of N-substituted saccharin and N-/O-substituted acesulfame derivatives were synthesized and tested as atypical and selective inhibitors of four different isoforms of human carbonic anhydrase (hCA I, II, IX and XII, EC 4.2.1.

Downscaling the in vitro test of fungal bioremediation of polycyclic aromatic hydrocarbons: methodological approach.

The miniaturization and optimization of a white rot fungal bioremediation experiment is described in this paper. The optimized procedure allows determination of the degradation kinetics of anthracene. The miniaturized procedure requires only 2.

Structural and Functional Characterization of the Enantiomers of the Antischistosomal Drug Oxamniquine.

Background: For over two decades, a racemic mixture of oxamniquine (OXA) was administered to patients infected by Schistosoma mansoni, but whether one or both enantiomers exert antischistosomal activity was unknown. Recently, a ~30 kDa S. mansoni sulfotransferase (SmSULT) was identified as the target of OXA action.

Comparison of nano and conventional liquid chromatographic methods for the separation of (+)-catechin-ethyl-malvidin-3-glucoside diastereoisomers.

Nano-liquid chromatography and conventional HPLC were used for the separation of diastereomers of (+)-catechin-ethyl-malvidin-3-glucoside. Those bridged anthocyanin dyes were obtained by reaction of (+)-catechin with malvidin-3-glucoside in the presence of acetaldehyde. Both diastereomers were isolated with semipreparative chromatography and their structures were confirmed by nuclear magnetic resonance and mass spectrometry.

Amino acids chemical stability submitted to solid state irradiation: the case study of leucine, isoleucine and valine.

A solid state radiolysis was conducted to examine the reactivity of amino acids towards high energy dose of gamma radiations. The presence of amino acids in the bulk of meteorites has raised the question of "if" and eventually "how" they could have been important in the development of life on Earth. The presence of radioactive elements in Solar System bodies could have played a crucial role in amino acids survival and in the formation of different organic molecules.

Use of a Novel Sub-2 µm Silica Hydride Vancomycin Stationary Phase in Nano-Liquid Chromatography. II. Separation of Derivatized Amino Acid Enantiomers.

A novel vancomycin silica hydride stationary phase was synthesized and the particles of 1.8 µm were packed into fused silica capillaries of 75 µm internal diameter (I.D.

Polyphenolic composition and antioxidant activity of the under-utilised Prunus mahaleb L. fruit.

Background: The identification of novel plant-based functional foods or nutraceutical ingredients that possess bioactive properties with antioxidant function has recently become important to the food, nutraceutical and cosmetic industries. This study evaluates the polyphenolic composition, identifies bioactive compounds and assays the total antioxidant capacity of Prunus mahaleb L. fruits collected from different populations and sampling years in the countryside around Bari (Apulia Region, Italy).

High-performance thin-layer chromatography for the evaluation of voacamine intracellular concentration related to its cytotoxic effect.

Previous investigations demonstrated that pretreatment with non-cytotoxic concentrations of voacamine had a chemosensitizing effect on cultured multidrug resistant osteosarcoma cells exposed to doxorubicin; whereas when used alone at high concentrations voacamine induced apoptosis-independent cell death on both sensitive and resistant cells. To gain insight into the mechanism of action of voacamine at the subcellular level, we developed an analytical high-performance thin-layer chromatography technique to assess the intracellular content of voacamine that could be correlated with the induction of cell death and consequent morphological and ultrastructural changes. The results of the quantitative analysis not only did allow us to measure both the amount of unmodified voacamine molecules (determined by the method) and the amount of molecules which reacted with cellular components (undetectable), but also to confirm the findings of our previous studies and support the validity of this method.

Untargeted NMR-based methodology in the study of fruit metabolites.

In this review, fundamental aspects of the untargeted NMR-based methodology applied to fruit characterization are described. The strategy to perform the structure elucidation of fruit metabolites is discussed with some examples of spectral assignments by 2D experiments. Primary ubiquitous metabolites as well as secondary species-specific metabolites, identified in different fruits using an untargeted 1H-NMR approach, are summarized in a comprehensive way.

The comparative study of a laccase-natural clinoptilolite-based catalyst activity and free laccase activity on model compounds.

For the first time a laccase from Trametes versicolor was immobilized on a natural clinoptilolite with Si/Al=5 to obtain a biocatalyst for environmental applications. Immobilization procedures exploiting adsorption and covalent binding were both tested, and only the last provided enough activity for practical applications. The optimal conditions for the immobilization of the enzyme on the support and the kinetic parameters for the free and covalent bonded laccase were determined.

Jasmonates elicit different sets of stilbenes in Vitis vinifera cv. Negramaro cell cultures.

The plant phenol trans-resveratrol, which is mainly found in grape, displays a wide range of biological effects. A cell suspension culture was developed from calli of grape leaves of Vitis vinifera cv. Negramaro in order to study the bioproduction of resveratrol.

Enantiomers separation by nano-liquid chromatography: use of a novel sub-2 μm vancomycin silica hydride stationary phase.

A novel sub-2 μm chiral stationary phase (CSP) was prepared immobilizing vancomycin onto 1.8 μm diol hydride-based silica particles. The CSP was packed into fused silica capillaries of 75 μm i.

Genetic introgression of ethylene-suppressed transgenic tomatoes with higher-polyamines trait overcomes many unintended effects due to reduced ethylene on the primary metabolome.

Ethylene regulates a myriad physiological and biochemical processes in ripening fruits and is accepted as the ripening hormone for the climacteric fruits. However, its effects on metabolome and resulting fruit quality are not yet fully understood, particularly when some of the ripening-associated biochemical changes are independent of ethylene action. We have generated a homozygous transgenic tomato genotype (2AS-AS) that exhibits reduced ethylene production as a result of impaired expression of 1-aminocyclopropane-1-carboxylate synthase 2 gene by its antisense RNA and had a longer shelf life.

Evaluation of the combination of a dispersive liquid-liquid microextraction method with micellar electrokinetic chromatography coupled to mass spectrometry for the determination of estrogenic compounds in milk and yogurt.

In this work, the suitability of a methodology based on dispersive liquid-liquid microextraction (DLLME) has been evaluated for the extraction of four endoestrogens (estriol, 17α-estradiol, 17β-estradiol, and estrone), an exoestrogen (17α-etynylestradiol), and a mycotoxin (zearalenone), together with some of their major metabolites (2-methoxyestradiol, α-zearalanol, β-zearalanol, α-zearalenol, and β-zearalenol) from different types of milk (whole and skimmed cow milk and semiskimmed goat milk) and whole natural yogurt. The methodology includes a previous protein precipitation with acidified ACN and a defatting step with n-hexane. Separation of the analytes, determination, and quantification were developed by MEKC coupled to ESI-MS using a BGE containing an aqueous solution of ammonium perfluorooctanoate as MS friendly surfactant.

Saffron Samples of Different Origin: An NMR Study of Microwave-Assisted Extracts.

An NMR analytical protocol is proposed to characterize saffron samples of different geographical origin (Greece, Spain, Hungary, Turkey and Italy). A microwave-assisted extraction procedure was developed to obtain a comparable recovery of metabolites with respect to the ISO specifications, reducing the solvent volume and the extraction time needed. Metabolite profiles of geographically different saffron extracts were compared showing significant differences in the content of some metabolites.

Effect of content of chiral selector and pore size of core-shell type silica support on the performance of amylose tris(3,5-dimethylphenylcarbamate)-based chiral stationary phases in nano-liquid chromatography and capillary electrochromatography.

In this study the separation performance of various chiral stationary phases (CSPs) made of polysaccharide-based chiral selectors coated onto superficially porous (core-shell or fused-core) silica supports were evaluated. The CSPs obtained by coating of various amounts of chiral selector (1-5%) onto supports of various pore size (100 and 300 Å) were studied. Their evaluation was pursued in both chiral nano-liquid chromatography (nano-LC) and chiral capillary electrochromatography (CEC).

Enantiomeric separation of new cathinone derivatives designer drugs by capillary electrochromatography using a chiral stationary phase, based on amylose tris(5-chloro-2-methylphenylcarbamate).

In this study, a chiral CEC method for the enantiomeric separation of ten cathinone derivatives, by means of a polysaccharide-based chiral stationary phase, has been developed. Capillary columns of 100 μm id packed with amylose tris(5-chloro-2-methylphenylcarbamate) coated on silica, also called Sepapak 3 or Lux Amylose-2, were used to achieve the enantioseparation of the studied designer drugs. Enantioresolution, chromatographic retention, and separation efficiency were evaluated in dependence of mobile-phase composition in terms of the content of the organic modifier, nature, and pH buffer.

Current applications of miniaturized chromatographic and electrophoretic techniques in drug analysis.

In the last decade, miniaturized separation techniques have become greatly popular in pharmaceutical analysis. Miniaturized separation methods are increasingly utilized in all processes of drug discovery as well as quality control of pharmaceutical preparation. The great advantages presented by the analytical miniaturized techniques, including high separation efficiency and resolution, rapid analysis and minimal consumption of reagents and samples, make them an attractive alternative to the conventional chromatographic methods for drug analysis.

Estrogenic compounds determination in water samples by dispersive liquid-liquid microextraction and micellar electrokinetic chromatography coupled to mass spectrometry.

In this work, a group of 12 estrogenic compounds, i.e., four natural sexual hormones (estrone, 17β-estradiol, 17α-estradiol and estriol), an exoestrogen (17α-ethynylestradiol), a synthetic stilbene (dienestrol), a mycotoxin (zearalenone) and some of their major metabolites (2-methoxyestradiol, α-zearalanol, β-zearalanol, α-zearalenol and β-zearalenol) have been separated and determined by micellar electrokinetic chromatography (MEKC) coupled to electrospray ion trap mass spectrometry.

HPLC determination of D-3-hydroxybutyric acid by derivatization with a benzofurazan reagent and fluorescent detection: application in the analysis of human plasma.

A simple and sensitive new method for the determination of D-3-hydroxybutyric acid (D-3-HBA) in human plasma after derivatization is described. The proposed method is based on the reaction of (2S)-2-amino-3-methyl-1-[4-(7-nitro-benzo-2,1,3-oxadiazol-4-yl)-piperazin-1-yl]-butan-1-one (NBD-PZ-Val) with D-3-HBA in the presence of O-(7-azobenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU) and N-ethyldiisopropylamine (DIEA) to produce a fluorescent derivative. The formed derivative was monitored fluorimetrically at λ(ex)=489 nm and λ(em)=532 nm.

Pressurized nano-liquid-junction interface for coupling capillary electrochromatography and nano-liquid chromatography with mass spectrometry.

A new nano-liquid-junction interface for coupling both capillary electrochromatography (CEC) or nano-liquid chromatography (nano-LC) with mass spectrometry (MS) was studied. The interface was a small T piece of polymeric material where capillary column and tip capillary were positioned at 180° while the third exit (at 90°) was occupied by a capillary delivering a liquid-assisting spray ionization for CEC experiments or by the electrode for the high voltage spray for nano-LC. Experiments were carried out analyzing mixtures of some organophosphorus pesticides (OPPs) or anti-inflammatory and related acidic drugs with MS detection in positive or negative ion mode, respectively.

Structural and functional alterations of cellular components as revealed by electron microscopy.

Scanning (SEM) and transmission electron microscopy (TEM) are two fundamental microscopic techniques widely applied in biological research for the study of ultrastructural cell components. With these methods, especially TEM, it is possible to detect and quantify the morphological and ultrastructural parameters of intracellular organelles (mitochondria, Golgi apparatus, lysosomes, peroxisomes, endosomes, endoplasmic reticulum, cytoskeleton, nucleus, etc.) in normal and pathological conditions.

Combination of two different stationary phases for on-line pre-concentration and separation of basic drugs by using nano-liquid chromatography.

Capillary columns were packed firstly with silica modified-teicoplanin (teico-CSP) particles for a short zone (1-5 cm) and then with a Cogent Bidentate C18 silica phase (25 cm). The first part of the column (inlet) was intended for focusing the sample model, consisted of selected basic compounds, while the second zone, containing RP18 particles, was used for their separation. For method optimization, some important experimental parameters were studied including the sample solvent, injected volume and teico-CSP particles length.