Thermoanalytical characterization of potentially schistosomicide polymeric derivatives

Oxamniquine (OXA) is a schistosomicide agent that causes some adverse effects in central nervous system. Intending to improve OXA therapeutic properties, a polymeric prodrug was designed. Currently, there is an increasing interest of thermal analytical techniques in the pharmaceutical area, so differential thermal analysis (DTA) and thermogravimetry (TG) were carried out to evaluate the thermal behavior of OXA, polymethacrylic acid (PMA), [poly(methacrylic-co-oxamniquine methacrylate)acid] (PMOXA) and physical mixture (OXA+PMA). The thermoanalytical profile of the physical mixture showed characteristic events of the thermal decomposition of OXA and PMA. Distinctly, PMOXA DTA curve did not show an endothermic peak at 148.5°C indicating that the drug was incorporated into the polymeric system. These results were corroborated by the IR spectroscopy and X-ray diffraction data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Determination of ochratoxin A in Portuguese rice samples by high performance liquid chromatography with fluorescence detection

A sensitive and accurate analytical method for the determination of ochratoxin A (OTA) in rice, based on extraction with phosphate-buffered saline/methanol, an immunoaffinity column (IAC) for clean-up, and high performance liquid chromatography with fluorescence detection (HPLC-FD), is described. The limit of quantification of the proposed method was 0.05 g kg^–1. Recovery of OTA from rice samples spiked at 0.05 g kg^–1 was 92%, with a within-day RSD of 5.4%. The proposed method was applied to 42 rice samples from Portugal and the presence of OTA was found in six samples at concentrations ranging from 0.09 to 3.52 g kg^–1. The identification of OTA was confirmed by methyl ester derivatization and then HPLC analysis. The daily intake of OTA by the Portuguese population was also estimated.     

Column liquid chromatographic determination of carbadox and olaquindox in feeds.

A column liquid chromatographic method for simultaneous determination of carbadox and olaquindox in swine feeds is described. The drugs were extracted from feeds with carbon tetrachloride-dimethylformamide (80:20) at 60 degrees C for 30 min. The extract was mixed with water (25:45). After centrifugation the aqueous layer was chromatographed on a reversed-phase column using gradient elution and ultraviolet detection at wavelengths of 305 and 262 nm. Recoveries from samples fortified at levels of 20-50 ppm were 92 +/- 9% for carbadox and 93 +/- 6% for olaquindox (means +/- standard deviations, n = 71).     

Coordination of the natural ligand lapachol to iron(II): synthesis,theoretical study and antiproliferative activity

Transition Metal Chemistry - Lapachol is a natural naphthoquinone known for having a variety of biological properties, and in recent years, it has been used in the synthesis of metal complexes with...     

On the identification of the nuclear forward glory in heavy-ion scattering

We present a simple method which enables us to identify the occurence of a forward glory in heavy ion scattering data. The method is successfully applied to the elastic scattering data of ¹²C (65 MeV), ¹³C (60 MeV), ¹⁵N (85 MeV) and ¹⁶O (75 MeV) on ²⁸Si. Received: 2 July 1999 / Revised version: 3 December 1999     

Structure elucidation and NMR assignments of two unusual monoterpene indole alkaloids from Psychotria stachyoides

Two unusual monoterpene indole alkaloids, stachyoside ( 1 ) and nor‐methyl‐23‐oxo‐correantoside ( 2 ), have been isolated from the aerial parts of Psychotria stachyoides. The structural elucidation of both compounds was performed by the aid of HRESIMS, FT‐IR, and 1D‐ and 2D‐NMR techniques including COSY, HSQC, HMBC, and NOESY. Copyright © 2010 John Wiley & Sons, Ltd.     

Assessment of teeth elemental content using μ‐EDXRF: effects by in‐office and at‐home bleaching products

The purpose of this in vitro study is to assess whether the elemental content of tooth enamel is altered when bleaching the teeth with bleaching gel. Because of tooth bleaching growing popularity and to match the public demands, manufacturers increased the range of bleaching products available, changing its presentation, techniques and concentration of active principles. This way, two different bleaching products were compared, one for in‐office and another for domestic use. In order to perform this evaluation, sound vestibular surfaces of anterior healthy teeth, extracted for periodontal or orthodontic reasons, were treated with the bleaching products accordingly to manufacturer instructions. Spectra were acquired using the M4 Tornado μ‐XRF setup, and quantitative calculations were performed using fundamental parameter method to determine the elemental composition of the analyzed samples before and after treatment. No significant statistical differences in the mineral content of the analyzed teeth were obtained. Copyright © 2014 John Wiley & Sons, Ltd.     

Characterization and Antineoplasic Effect of Extracts Obtained from <Emphasis Type="Italic">Pleurotus sajor</Emphasis>-<Emphasis Type="Italic">caju</Emphasis> Fruiting Bodies

Fungi of the Pleurotus genus present a great industrial interest due to their possibility of producing pharmacological compounds, pigments, aromas, organic acids, polysaccharides, enzymes, vitamins, amino acids, etc. Among the therapeutic products, we can highlight those with antineoplasic activity, attributed to the fungi cell wall components. Based on this, the objective of this work was to study the antineoplasic capacity of the polysaccharidic fractions obtained from Pleurotus sajor-caju fruiting bodies. Female Swiss mice were inoculated with the Ehrlich ascitic tumor (5 × 10⁶ cells/animal) in ascitic form. The polysaccharidic fractions were administered intraperitoneally, during a 6-day period. Fractions FI and FII presented a lower volume of ascitic liquid (3.1 and 1.8 mL, respectively) and a higher reduction in the number of neoplasic cells present in the ascitic liquid (86.2% and 85%, respectively), when compared to the positive control (group inoculated with the tumor but without treatment). These fractions were characterized in terms of monosaccharide composition. Glucose was the major component detected, followed by galactose and mannose. The anomeric carbon configuration of the β-glucan was confirmed by the ¹³C NMR (δ 103.7). Substituted and free C3 and C6 were also detected. Protein bands were confirmed through infrared analysis.     

Determination of fumonisins B1 and B2 in Portuguese maize and maize-based samples by HPLC with fluorescence detection

Fumonisins B₁ (FB₁) and fumonisin B₂ (FB₂) are the main members of a family of mycotoxins produced by Fusarium verticillioides, Fusarium proliferatum, and other fungi species of the section Liseola. The present work shows the results of comparative studies using two different procedures for the analysis of fumonisins in maize and maize-based samples. The studied analytical methods involve extraction with methanol/water, dilution with PBS, and clean-up through immunoaffinity columns. Two reagents (o-phthaldialdehyde and naphthalene-2,3-dicarboxaldehyde) were studied for formation of fluorescent derivatives. The separation and identification were carried out by high-performance liquid chromatography with fluorescence detection. The optimized method for analysis of fumonisins in maize involved extraction with methanol/water (80:20), clean-up with an immunoaffinity column, and derivatization with naphthalene-2,3-dicarboxaldehyde (NDA). The limit of detection was 20 μg kg⁻¹ for FB₁ and 15 μg kg⁻¹ for FB₂. Recoveries of FB₁ and FB₂ ranged from 79% to 99.6% for maize fortified at 150 μg kg⁻¹ and 200 μg kg⁻¹, respectively, with within-day RSDs of 3.0 and 2.7%. The proposed method was applied to 31 samples, and the presence of fumonisins was found in 14 samples at concentrations ranging from 113 to 2,026 μg kg⁻¹. The estimated daily intake of fumonisins was 0.14 μg kg⁻¹ body weight per day.