Synthesis and Characterization of Canola-Based Cholesteryl Ester and Nematic E7 Mixture

Abstract

The fatty acid of Canola Oil, 61% of which is Oleic acid, was extracted. Fourier Transform Infrared Spectrophotometry (FTIR) confirmed the fatty acid extraction. Canola-based Cholesteryl Ester (CANCE) was obtained through esterification. FTIR scans of the CANCE and the fatty acid were compared to verify the complete esterification. The resulting crude product is a yellow wax with some crystals embedded on it. Thin layer chromatography was then performed to determine the appropriate solvent for the column chromatography to purify the crude sample. The purified product was characterized using Optical Polarizing Microscopy and Differential Scanning Calorimetry. Mixtures of the Nematic E7 and CANCE in different ratios were prepared. Transition temperatures of each mixture were determined using differential scanning calorimetry and verified using optical polarizing microscopy.     

Microcionamides A and B, bioactive peptides from the philippine sponge Clathria (Thalysias) abietina

Microcionamides A (1) and B (2) have been isolated from the Philippine marine sponge Clathria (Thalysias) abietina. These new linear peptides are cyclized via a cystine moiety and have their C-terminus blocked by a 2-phenylethylenamine group. Their total structures, including absolute stereochemistry, were determined by a combination of spectral and chemical methods. Compound 1 was shown to slowly isomerize about the C-36/C-37 double bond when stored in DMSO. Microcionamides A (1) and B (2) exhibited significant cytotoxicity against the human breast tumor cells lines MCF-7 and SKBR-3 and displayed inhibitory activity against Mycobacterium tuberculosis H(37)Ra.     

Analysis of polymeric phenolics in red wines using different techniques combined with gel permeation chromatography fractionation

A multiple-step analytical method was developed to improve the analysis of polymeric phenolics in red wines. With a common initial step based on the fractionation of wine phenolics by gel permeation chromatography (GPC), different analytical techniques were used: high-performance liquid chromatography-diode array detection (HPLC-DAD), HPLC-mass spectrometry (MS), capillary zone electrophoresis (CZE) and spectrophotometry. This method proved to be valid for analyzing different families of phenolic compounds, such as monomeric phenolics and their derivatives, polymeric pigments and proanthocyanidins. The analytical characteristics of fractionation by GPC were studied and the method was fully validated, yielding satisfactory statistical results. GPC fractionation substantially improved the analysis of polymeric pigments by CZE, in terms of response, repeatability and reproducibility. It also represented an improvement in the traditional vanillin assay used for proanthocyanidin (PA) quantification. Astringent proanthocyanidins were also analyzed using a simple combined method that allowed these compounds, for which only general indexes were available, to be quantified.     

Strawberry Juice Powders: Effect of Spray-Drying Conditions on the Microencapsulation of Bioactive Components and Physicochemical Properties

The drying of fruit juices has advantages such as easy handling of powders, reduction in volume, and preservation of the characteristics of the fruit. Thus, in this work, the effect of the spray drying conditions of strawberry juice (SJ) with maltodextrin (MX) as a carrying agent on the microencapsulation of bioactive compounds and physicochemical properties was studied. The content of phenolic compounds and antioxidant activity showed higher values at low concentrations of MX, while the effect of drying temperature was negligible. The thermal characterization showed that the low molecular weight sugars in the juice decreased the glass transition temperature (Tg). The morphological analysis by scanning electron microscopy (SEM) indicated that at low concentrations of MX, the particles agglomerated, while at intermediate and high concentrations, the particles were observed as well separated. Through microstructural analysis by X-ray diffraction (XRD), the presence of amorphous state was confirmed in all the samples, which is beneficial for preventing chemical and biochemical reactions, and promoting the conservation of the microencapsulated bioactive compounds.     

Density Functional Tight-Binding Studies of Carbon Nanotube Structures

A density functional tight-binding self-consistent charge approach has been used to study the structures and elastic properties of nine model carbon nanotubes of different helicities and diameters between 5.5 and 10.8 A. The systems contain from 112 to 268 atoms and were optimized under periodic boundary conditions in the axial direction. Both the carbon networks and the overall tube dimensions were optimized. Most of the C—C bond lengths are slightly lengthened relative to graphene (two-dimensional graphite); the others remain essentially the same or are shorter. There is overall a longitudinal compression of the tube. The strain energy per atom, relative to graphene, varies inversely with the square of the tube radius. The Young's moduli decrease with increasing radius but do not depend upon chirality. The Poisson ratios are nearly constant. The consequences of removing an electron from each system were also investigated. In most instances, the tube dimensions were little affected; in only a few cases is there a change in length or radius (positive or negative) as large as 0.10%. The Young's moduli remain the same as for the neutral systems, but the Poisson ratios tend to increase for metals and semimetals and to decrease for semiconductors.     

Chromophores in cellulosics, VI. First isolation and identification of residual chromophores from aged cotton linters

In the present work, aged cotton linters have been analyzed for their chromophore content according to the CRI (“chromophore release & identification”) method. Despite the very low contents in the ppb range, nine chromophores have been unambiguously identified, which makes this account the first one on defined chromophoric structures isolated from cotton. A common feature of the chromophores are 2-hydroxy-[1,4]benzoquinone, 2-hydroxyacetophenone and 5,8-dihydroxynaphthoquinone moieties, which resemble chromophoric structures found in other cellulosic substrates, such as bleached pulps or fibers. The finding of these compounds in lignin-free cotton linters confirms the previous hypothesis that those chromophores are formed from (oxidized) carbohydrate structures rather than from lignin fragments.     

Effect of Sonication Treatment and Maceration Time in the Extraction of Polysaccharide Compounds during Red Wine Vinification

The application of high-power ultrasounds (US) at 28 kHz to the crushed grapes and the use of different pomace contact times caused changes in the content and composition of monosaccharides and polysaccharides in the musts and wines. These differences were maintained from the moment of pressing (end of maceration) until the end of the alcoholic fermentation. The US increased the content of monosaccharides and polysaccharides in the musts by facilitating their extraction from the solid parts during maceration. The application of medium maceration time (3 days) to sonicated grapes led to an extraction of polysaccharides rich in arabinose and galactose, rhamnogalacturonan type II (RG-II) and mannoproteins (MP), similar to that observed in the control wines made with an extended maceration of 7 days (968.21 vs. 1029.45; 895.04 vs. 1700.50; 356.81 vs. 343.95, respectively). This fact was attributed to a higher extraction in the must during the sonication process and to an important release of pectic polysaccharides during the pressing of the sonicated pomace, which is reported here for the first time. Therefore, the US technology could be useful for increasing the polysaccharide content in the wines or for reducing the maceration time needed to achieve certain levels of wine polysaccharides.     

Green approach to the extraction of major capsaicinoids from habanero pepper using near-infrared,microwave, ultrasound and Soxhlet methods,a comparative study

A simple method for the extraction of two major capsaicinoids from habanero peppers, using near-infrared irradiation, microwave irradiation or ultrasound as the energy source and ethanol as the solvent, was compared with Soxhlet extraction. The extraction processes were monitored by gas chromatography/mass spectrometry. The new processes offer better overall yields and a higher ratio of capsaicin to dihydrocapsaicin than Soxhlet extraction. The physical effect of the different energy sources on the peppers was determined using scanning electron microscopy. Extraction of capsaicin and dihydrocapsaicin using near-infrared irradiation, which has not been previously reported, was shown to be a simple and efficient alternative extraction procedure.     

Computed electrostatic potentials and average local ionization energies on the molecular surfaces of some tetracyclines

The electrostatic potentials and average local ionization energies computed on the molecular surfaces of four tetracyclines have been investigated with the objective of identifying common features as well as subtle differences that may be related to their biological activities. The four are the parent molecule tetracycline, chlortetracycline, oxytetracycline, and doxycyline. The calculations were carried out at the HF/STO‐3G*//STO‐3G* level. Our electrostatic potential results show that each molecule has a large negative region that extends along its lower portion, consistent with its ability to complex Ca²⁺ and Mg²⁺ ions. Although the surface electrostatic potentials of the four tetracyclines show many similarities, our statistical measure of local polarity allows us to label doxycycline as the one with the lowest degree of local polarity, consistent with its longer half‐life in vivo. The regions in the tetracyclines with the most reactive electrons are the amide nitrogen lone pairs and certain carbons of the outermost rings. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 82: 160–169, 2001     

A novel 2-(2-methyl-2-nitrovinyl)-furan ectoparasitic drug: physicochemical characterization and determination of the raw material by gas chromatography mass spectrometry

2-(2-methyl-2-nitrovinyl)-furan (NVF) has recently been synthesized and the pharmaceutical industry interest in this compound has grown due to its antibacterial, fungicidal and anti-ectoparasitic activities. Therefore, the physicochemical characterization of new drug was conducted. In addition, two rapid, simple and suitable GC methods were developed for determination of NVF. Analyses were carried out with an Agilent DB-5ms capillary column (60 m × 0.25 mm i.d., 0.25 µm film thickness). The GC-FID analysis employed splitless mode of injection, oven/injector/detector temperature of 160/230/280°C and nitrogen carrier at the flow of 5.0 mL min^?1. The GC-MS analysis employed splitless mode of injection, helium carrier at the flow of 1.5 mL min^?1, column temperature program with 2 min at 100°C, ramp at 50°C min^?1 to 260°C and injector and detector temperature of 250 and 290°tC, respectively. The MS conditions were ionization voltage, 70 eV; mass range, m/z 40–350; and ion source temperature, 200°C. The analysis time took less than 6 min. The results obtained in the validation of the methods suggest that these methods are economic, precise, accurate and linear over the range of analysis. The methods were successfully employed during the synthesis of NVF in order to ensure the quality of the raw material.