Novel reactive thermosensitive polyethers – control of transition point

A new class of thermosensitive polymers based on polyethers is discussed. Using living anionic polymerisation techniques a series of homo- and block copolymers of 2,3-epoxypropanol-1 (the glycidol), ethoxy ethyl glycidol ether, its hydrophobic derivative, and ethylene oxide of different molar masses and topology (linear and comb-like) was obtained. By simple chemical modification of hydroxyl groups in polyglycidol segments hydrophobic elements were introduced into polymer chains, which allowed to control the transition point related to the lower critical solution temperature between 0 to 100°C. The relation between the transition temperature and the structure of obtained polymers is discussed.     

Changes in Antioxidant Properties and Amounts of Bioactive Compounds during Simulated In Vitro Digestion of Wheat Bread Enriched with Plant Extracts

Cereal preparation can be an excellent source of substances with proven health-promoting properties. Unfortunately, some types of bread, such as white flour bread, are devoid of many valuable nutrients. Therefore, it is necessary to look for ways to increase its density and nutritional value. The aim of the study was to investigate the effect of stabilized plant extracts on the quality of bread, its antioxidant activity and polyphenol content, and to evaluate the stability of bioactive compounds and antioxidant activity during in vitro digestion. The research material was the wheat bread baked with spray dried microcapsules of hawthorn bark, soybeans and onion husks in maltodextrin or inulin carriers. The addition of plant extracts resulted in the presence of phenolic compounds in the wheat bread, and its antioxidant activity significantly increased. There was no significant difference in antioxidant activity between breads containing microcapsules with different carriers. During in vitro digestion, procyanidins and isoflavones in bread were more resistant to the digestive processes than other compounds. The antioxidant activity during simulated digestion was the highest at the stage of gastric digestion, and its value depended on the extract used and the analytical method applied.     

210Po in popular medicinal herbs from Poland

Herbs are an important part of traditional medicine in Poland. Therefore, the aim of this study was the determination of polonium ²¹⁰Po in 48 selected medicinal herb samples from the Polish market. The activity concentrations of ²¹⁰Po were measured using alpha spectrometry. The activity concentration of ²¹⁰Po was in the range from 0.3?±?0.1 to 28.2?±?0.4 Bq kg^–1. The obtained results were compared with corresponding studies conducted worldwide. A higher ²¹⁰Po activity concentration was observed in the above-ground part of plants. The obtained results show that the highest ²¹⁰Po activity concentration was observed in evergreen plants and winter-hardy plants. Yet even infusions with 2 g of the most contaminated herbs examined were considered to be radiologically safe.     

Mechanistic Insight into Formation of Oxo‐Iron(IV) Porphyrin π‐Cation Radicals from Enzyme Mimics of Cytochrome P450 in Organic Solvents

Two new models for cytochrome P450 in which the thiolate axial ligand is replaced by an RSO₃^? group, form oxo‐iron(IV) porphyrin π‐cation radicals as sole oxidation products in “peroxo shunt” reactions (see scheme) independent of the nature of the employed solvent (polar or non‐polar) and electronic nature of the porphyrin rings.

     

Axial ligand and spin-state influence on the formation and reactivity of hydroperoxo-iron(III) porphyrin complexes

The present study focuses on the formation and reactivity of hydroperoxo-iron(III) porphyrin complexes formed in the [Fe(III)(tpfpp)X]/H(2)O(2)/HOO(-) system (TPFPP=5,10,15,20-tetrakis(pentafluorophenyl)-21H,23H-porphyrin; X=Cl(-) or CF(3) SO(3)(-)) in acetonitrile under basic conditions at -15 °C. Depending on the selected reaction conditions and the active form of the catalyst, the formation of high-spin [Fe(III)(tpfpp)(OOH)] and low-spin [Fe(III)(tpfpp)(OH)(OOH)] could be observed with the application of a low-temperature rapid-scan UV/Vis spectroscopic technique. Axial ligation and the spin state of the iron(III) center control the mode of O-O bond cleavage in the corresponding hydroperoxo porphyrin species. A mechanistic changeover from homo- to heterolytic O-O bond cleavage is observed for high- [Fe(III)(tpfpp)(OOH)] and low-spin [Fe(III)(tpfpp)(OH)(OOH)] complexes, respectively. In contrast to other iron(III) hydroperoxo complexes with electron-rich porphyrin ligands, electron-deficient [Fe(III)(tpfpp)(OH)(OOH)] was stable under relatively mild conditions and could therefore be investigated directly in the oxygenation reactions of selected organic substrates. The very low reactivity of [Fe(III)(tpfpp)(OH)(OOH)] towards organic substrates implied that the ferric hydroperoxo intermediate must be a very sluggish oxidant compared with the iron(IV)-oxo porphyrin π-cation radical intermediate in the catalytic oxygenation reactions of cytochrome P450.     

1H NMR study of the kinetics of substituted aniline polymerization. II. Copolymerization of 2‐methoxyaniline and 3‐aminobenzenesulfonic acid

We investigated the kinetics of the oxidative chemical copolymerization of 2‐methoxyaniline (OMA) and 3‐aminobenzenesulfonic acid (MA) by monitoring monomer depletion with ¹H NMR spectroscopy. We adapted a semiempirical kinetic model, previously used for OMA homopolymerization, for the consumption of both OMA and MA monomers with a large difference in their reactivities. The OMA polymerization rate and end conversion showed a similar dependence on the reaction conditions, as described in the first part of this series, for its homopolymerization. Generally, the MA comonomer had an inhibition effect on the OMA polymerization rate. However, an increase in the initial MA concentration resulted in an increased OMA initiation rate. Because of the higher reactivity of OMA compared with that of MA, the OMA conversion began before the MA conversion, and both the initiation and propagation rates were higher than those for MA. The molar ratios of the converted monomers (MA/OMA) were always significantly lower than the corresponding MA/OMA feed fractions. They depended on the reaction conditions used for the copolymerization. In particular, higher oxidant or MA concentrations, higher temperatures, and a 1 M DCl concentration favored MA conversion, that is, its insertion into the copolymer. The MA end conversion was much smaller than that of OMA, only up to 23%; for a low oxidant concentration (oxidant/monomer‐deficient molar ratio), it was only 6%. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2482–2493, 2001     

An unusual nicotinamide derivative, 4-pyridone-3-carboxamide ribonucleoside (4PYR), is a novel endothelial toxin and oncometabolite

Our recent studies identified a novel pathway of nicotinamide metabolism that involves 4-pyridone-3-carboxamide-1-β-D-ribonucleoside (4PYR) and demonstrated its endothelial cytotoxic effect. This study tested the effects of 4PYR and its metabolites in experimental models of breast cancer. Mice were divided into groups: 4T1 (injected with mammary 4T1 cancer cells), 4T1 + 4PYR (4PYR-treated 4T1 mice), and control, maintained for 2 or 21 days. Lung metastasis and endothelial function were analyzed together with blood nucleotides (including 4PYR), plasma amino acids, nicotinamide metabolites, and vascular ectoenzymes of nucleotide catabolism. 4PYR metabolism was also evaluated in cultured 4T1, MDA-MB-231, MCF-7, and T47D cells. An increase in blood 4PYR in 4T1 mice was observed at 2 days. 4PYR and its metabolites were noticed after 21 days in 4T1 only. Higher blood 4PYR was linked with more lung metastases in 4T1 + 4PYR vs. 4T1. Decreased L-arginine, higher asymmetric dimethyl-L-arginine, and higher vascular ecto-adenosine deaminase were observed in 4T1 + 4PYR vs. 4T1 and control. Vascular relaxation caused by flow-dependent endothelial activation in 4PYR-treated mice was significantly lower than in control. The permeability of 4PYR-treated endothelial cells was increased. Decreased nicotinamide but enhanced nicotinamide metabolites were noticed in 4T1 vs. control. Reduced N-methylnicotinamide and a further increase in Met2PY were observed in 4T1 + 4PYR vs. 4T1 and control. In cultured breast cancer cells, estrogen and progesterone receptor antagonists inhibited the production of 4PYR metabolites. 4PYR formation is accelerated in cancer and induces metabolic disturbances that may affect cancer progression and, especially, metastasis, probably through impaired endothelial homeostasis. 4PYR may be considered a new oncometabolite.Subject terms: Mechanisms of disease, Pathogenesis, Breast cancer     

Cornelian Cherry (Cornus mas L.) Extracts Exert Cytotoxicity in Two Selected Melanoma Cell Lines—A Factorial Analysis of Time-Dependent Alterations in Values Obtained with SRB and MTT Assays

Despite the fact that phytochemicals of Cornaceae species have long been discussed as possible auxiliary agents in contemporary treatment, the insights on their properties remain relatively scarce. This study focuses on Cornus mas L. (Cornelian cherry), the extracts of which are reported to exert a pleiotropic effect shown in both in vivo and in vitro studies. This study aimed to explore the cytotoxic effect of extracts from fruits of red (Cornus mas L. ‘Podolski’) and yellow (Cornus mas L. ‘Yantarnyi’ and ‘Flava’) Cornelian cherries on two melanoma cell lines (A375 and MeWo). The extracts were characterized in the context of the concentration of bioactive compounds of antioxidative properties. Cytotoxicity was investigated with the use of the following two assays: SRB and MTT. An additional, alternative protocol for the SRB assay was used in this study so as to account for possible bias. Cytotoxicity was assessed as a difference in the whole time series of cell viability, instead of analyzing differences in raw values (often found in the literature). Both extracts from Cornus mas L. induced cytotoxicity in both A375 and MeWo cell lines, although the response of these cells was different. Moreover, based on this study, there is no evidence for claiming a different magnitude of cytotoxicity between these two extracts.     

Buckwheat Hull-Enriched Pasta: Physicochemical and Sensory Properties

This work aimed to evaluate the effect of partial replacement of semolina with 0, 1, 5, 10, 15, and 20% of ground buckwheat hull (BH) on the chemical composition, antioxidant properties, color, cooking characteristics, and sensory properties of wheat pasta. Pasta samples were prepared by dough lamination (tagliatelle shape) and dried at 55 °C until the moisture content was 11–12% (wet basis). Analyses of samples showed that the addition of BH caused an increase in fiber content in pasta from 4.31% (control pasta) to 14.15% (pasta with 20% of BH). Moreover, the brightness and yellowness of BH-enriched products were significantly decreased compared to the control sample, and the total color difference ranged from 23.84 (pasta with 1% of BH) to 32.56 (pasta with 15% BH). In addition, a decrease in optimal cooking time, as well as an increased weight index and cooking loss, was observed in BH-enriched pasta samples. Furthermore, BH-enriched cooked pasta had significantly higher total phenolic content and antioxidant activity but an unpleasant smell and taste, especially if the level of BH was higher than 10%.     

The DI-SPME Method for Determination of Selected Narcotics and Their Metabolites,and Application to Bone Marrow and Whole Blood Analysis

The present investigation utilised the quick and easy SPME/LC-MS method to determine selected narcotic substances and their metabolites in whole blood. The study included qualitative analysis and validation of the method. Analytes were determined in the linearity range of 25–300 ng/mL. The precision during and between days (in general CV < 13.41%), and the LOD which results in between 0.36 and 11.08 ng/mL, and the LOQ between 1.20 and 36.90 ng/mL were investigated. The validation results obtained, as well as the results of subsequent in-laboratory tests, confirmed the applicability of the method in the analysis of blood samples. An attempt to apply the method to the analysis of bone marrow samples has yielded promising results; however, more detailed studies are needed in this area.