Anna Maria A. P. Fernandes

Lignans and a neolignan from Virola oleifera leaves

The chlorophyll-free dichloromethane fraction of the ethanolic extract from leaves of Virola oleifera yielded four new natural lignans, including a

Nanoassisted Laser Desorption-Ionization-MS Imaging of Tumors

The ability of nanoassisted laser desorption-ionization mass spectrometry (NALDI-MS) imaging to provide selective chemical monitoring with proper spatial distribution of lipid profiles from tumor tissues after plate imprinting has been tested. NALDI-MS imaging identified and mapped several potential lipid biomarkers in a murine model of melanoma tumor (inoculation of B16/F10 cells). It also confirmed that the in vivo treatment of tumor bearing mice with synthetic supplement containing phosphoethanolamine (PHO-S) promoted an accentuated decrease in relative abundance of the tumor biomarkers. NALDI-MS imaging is a matrix-free LDI protocol based on the selective imprinting of lipids in the NALDI plate followed by the removal of the tissue. It therefore provides good quality and selective chemical images with preservation of spatial distribution and less interference from tissue material. The test case described herein illustrates the potential of chemically selective NALDI-MS imaging for biomarker discovery.

Fluoro-Jade, but not Fluoro-Jade B, stains non-degenerating cells in brain and retina of embryonic and neonatal rats.

Fluoro-Jade (FJ) and Fluoro-Jade B (FJB) are fluorescein derivatives currently used to stain brain cells under degeneration. In this study, we investigated the FJ staining of nondegenerating cells in embryonic and neonatal rat brain and retina. In embryonic rat brain (embryonic day 15; E15), very intense staining of cells was observed. The number of FJ-stained cells and the intensity of staining decreased with increasing in animal age, being almost absent by postnatal day 16 (P16). Only a few cells in neonatal rat brain were in the process of cell death, as verified by the TUNEL technique. The FJ-stained cells in neonatal brain were positive for the neuronal marker neuronal nuclei antigen (NeuN). In retina, FJ stained mainly cells from the ganglion cell layer at P2 and the neuroblastic layer at P2 and P6. In contrast to FJ, FJB did not stain nondegenerating cells in embryonic and neonatal rats. These results show that in addition to staining degenerating brain cells, FJ also stains nondegenerating central nervous system cells in embryonic and neonatal stages.

Quantitation of triacylglycerols in vegetable oils and fats by easy ambient sonic-spray ionization mass spectrometry

This innovative mass spectrometric technique provides simple, quick, and reliable quantitative analysis of triacylglycerols in vegetable oils and fats. The easy ambient sonic-spray ionization mass spectrometry (EASI-MS) technique provides simple, quick, and reliable qualitative analysis of triacylglycerols (TAG) in vegetable oils. The use of this ambient mass spectrometry technique, which does not require separation or derivatization before analysis, for precise quantitative analyses has yet to be demonstrated. In this study, the TAG composition of edible vegetable oils, hydrogenated vegetable oils and cocoa butter was quantitated by EASI-MS. The results were compared with those obtained by theoretical predictions of the TAG composition performed by a software projection, which uses a mathematical algorithm of distribution of the fatty acids (FA) in the TAG molecule, and by the direct gas chromatography method (GC-FID). Acceptable correlation coefficients were observed between the three methods during the analysis of vegetable oils and hydrogenated vegetable oils. EASI-MS offers not only simplicity, speed and selectivity for oil analysis but also precise quantitation of the TAG composition. Therefore, EASI-MS is a promising substitute for the more demanding and time-consuming standard protocols, which require separation and sometimes derivatization before analysis.

Absolute configuration of the lignan oleiferins from Virola oleifera

Abstract The assignment of the absolute configuration for the lignan-7-ols, (7R,8S,8′R)-oleiferins AC, was established by acid catalysed Friedel—Crafts-type cyclization for the known 2,7′-cyclolignans and chemical analyses.

A Method to Separate Lignoids fromVirolaLeaves

The genus Virola (Myristicaceae) comprises approximately 35 species which are distributed in neotropical countries (Rodrigues, 1980). Their geographical and taxonomic distribution has been used in studies of chemical ecology (Paulino Filho, 1985), especially of the Amazon forest. The bark resin, derived from various Virola species, provides hallucinogenic snuff and an arrow poison, and the species has thus attracted phytochemical examination (Holmstedt et al., 1980). The genus is well known to be an abundant source of lignans and neolignans, and its important physiological actions have been reported (MacRae and Towers, 1985). A particularly striking finding is the observed high levels of lignoids found in human urine (enterolignans), following dietary intake of vegetable fibre and grain (Bannwart et al., 1989), which have been suggested to have cancer-protective effects (Adlercreutz et al., 1991). Investigations of lignoids in plants were mainly carried out with trunk wood (Fernandes, J. B. et al., 1980), bark, fruit (Lemus and Castro, 1989), fruit pericarp, aril, seed coat and kernel (Kato et al., 1990), while little is known of the distribution of these compounds in the leaves (Martinez et al., 1985). The apparent lack of phytochemical data may be due in part to the nature of the crude extracts of Virola leaves, which generally yield a sticky residue composed of chlorophylls and other colouring matters which are difficult to resolve by chromatographic methods. The general procedure for the removal of colouring matter from plant leaves includes the treatment of green extracts with freshly activated charcoal or by passing through a charcoal column (Nair et al., 1990), as well as by lead acetate adsorption. There are, however, disadvantages to these procedures: metabolite losses can occur through occlusion in the precipitate and a residuum of lead acetate remains in solution and can cause problems in subsequent stages. As part of our continuous research work on the Virola, we have examined the lignoid constituents of the leaves of V. surinamensis (Rol.) Warb. (Barata et al., 1978; Queiroz Paulo, 1982; Santos and Barata, 1990) of V. oleifera (Schott) A. C. Smith (Fernandes, A. M. A. P. et al., 1993, 1994) and of V. pavonis (A. DC.) A. C. Smith (Ferri and Barata, 1991, 1992). The crude extracts of the leaves were systematically submitted to chlorophyll elimination yielding purified fractions free of colouring matter and rich in lignoid mixtures. This resulted in the isolation of seventeen lignoids, including nine new compounds. The present work describes the use of this simplified methodology for an efficient separation of the lignans and neolignans from apolar and polar crude extracts of the leaves of V. oleifera and V. pavonis.

Long-chain acyl-CoA synthetase 6 regulates lipid synthesis and mitochondrial oxidative capacity in human and rat skeletal muscle.

Long‐chain acyl‐CoA synthetase 6 (ACSL6) mRNA is present in human and rat skeletal muscle, and is modulated by nutritional status: exercise and fasting decrease ACSL6 mRNA, whereas acute lipid ingestion increase its expression. ACSL6 genic inhibition in rat primary myotubes decreased lipid accumulation, as well as activated the higher mitochondrial oxidative capacity programme and fatty acid oxidation through the AMPK/PGC1‐α pathway. ACSL6 overexpression in human primary myotubes increased phospholipid species and decreased oxidative metabolism.

Direct Visualization of Neurotransmitters in Rat Brain Slices by Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI - MS)

AbstractMass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials. The amino acids γ-aminobutyric (GABA), glutamate, aspartate, serine, as well as acetylcholine, dopamine, and choline were successfully imaged using a commercial DESI source coupled to a hybrid quadrupole-Orbitrap mass spectrometer. The spatial distribution of the analyzed compounds in different brain regions was determined. We conclude that the ambient matrix-free DESI-MSI is suitable for neurotransmitter imaging and could be applied in studies that involve evaluation of imbalances in neurotransmitters levels. Graphical Abstractᅟ

Desorption/ionization efficiencies of triacylglycerols and phospholipids via EASI-MS

Knowledge of the major effects governing desorption/ionization efficiency is required for the development and application of ambient mass spectrometry. Although all triacylglycerols (TAG) have the same favorable protonation and cationization sites, their desorption/ionization efficiencies can vary dramatically during easy ambient sonic-spray ionization because of structural differences in the carbon chain. To quantify this somewhat surprising and drastic effect, we have performed a systematic investigation of desorption/ionization efficiencies as a function of unsaturation and length for TAG as well as for diacylglycerols, monoacylglycerols and several phospholipids (PL). Affinities for Na(+) as a function of unsaturation level have also been assayed via comprehensive metadynamics calculations to understand the influence of this phenomenon on the ionization efficiency. The results suggest that dipole-dipole interactions within a carbon chain tuned by unsaturation sites govern ionization efficiency of TAG and PL.

Phospholipid Profile and Distribution in the Receptive Oviduct and Uterus During Early Diestrus in Cattle

ABSTRACT Phospholipid metabolism and signaling influences on early pregnancy events in cattle are unknown. This study aimed to characterize global phospholipid composition of oviduct and uterus during early diestrus in a model of contrasting embryo receptivity. Beef cows were treated to ovulate a larger (LF-LCL group, associated with greater receptivity) or smaller (SF-SCL group) follicle and, consequently, to present greater or smaller plasma concentrations of estradiol during proestrus-estrus, as well as progesterone during early diestrus. Oviduct and uterus (4 days after gonadotropin-releasing hormone-induced ovulation; D4) as well as the uterus (D7) were collected, and lipid profiles were monitored by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). This technique allowed the identification and tissue localization of sphingomyelins (SM), phosphatidylcholines (PC), ceramides (Cer), and phosphatidylethanolamines (PE). Multivariate statistics were used to separate samples into groups with distinctly different phospholipid profiles in the uterus at D4 and D7. Different abundance of ions corresponding to specific lipids were detected on D4 (Cer [42:1], PC [31:0], PC [32:1], PC [34:4], and PC [36:4] greater for LF-LCL group; and PC [38:7], PC [38:5], PC [38:4], PC [40:7], and PC [40:6] greater for SF-SCL group) and D7 (SM [34:2], SM [34:1], PC [32:1], and PC [35:2] greater for LF-LCL group). The MALDI-MS imaging showed the spatial distributions of major phospholipids. In conclusion, distinct phospholipid profiles were associated with animals treated to show contrasting receptivity to the embryo. Functional roles of the identified phospholipids on uterine function and preimplantation embryo development deserve further studies.