Agata Górska

Adamantylaminopyrimidines and -pyridines are potent inducers of tumor necrosis factor-α

A series of (1-adamantyl)aminopyrimidine and -pyridine derivatives was prepared by adamantyl cation attack on amino heterocycles. The adamantylated compounds, particularly 2-(1-adamantyl)amino-6-methylpyridine, were found to be potent TNF-alpha inducers in murine melanoma cells transduced with gene for human TNF-alpha.

An assessment of various powdered baby formulas by conventional methods (DSC) or FT-IR spectroscopy

Milk components are assumed to be uniformly distributed in a concentrate whilst it is being dried. During milk powder production, these components are redistributed in the drying droplets and the powder surface composition is significantly different from that of the bulk of it. The objective of this article was to analyze and compare phase transitions of powdered baby formulas as well as to make a study of their FT-IR spectra. Food powders of different composition were tested by a differential scanning calorimeter (DSC, TA Instruments Q 200) with a normal pressure cell and a System 2000 spectrophotometer. Significant differences were observed in the shape of curves of the mixtures and the agglomerates. The observed phase transitions in powders depended on fat content. Characteristic peaks of melting lactose were observed in the curves of the powdered baby formulas. The IR spectra proved to be useful in determining adulteration of baby formulas. Both methods were complimentary during a thorough evaluation of these food powders.

Oxidative stability and triacylglycerols structure of lipid fraction from cookies for infants

The aim of this research was to analyse the quality of the lipid fraction extracted from commercially available cookies intended for infants. The composition, fatty acid distribution and oxidative stability of fats, interpreted as the resistance of fats against autooxidation, were studied. In addition, the kinetic parameters of the oxidation process, such as activation energies (Ea), pre-exponential factors (Z) and reaction rate constants (k) for fat oxidation under the differential scanning calorimetry tests conditions were calculated using the Ozawa–Flynn–Wall method and the Arrhenius equation. The distribution of fatty acids in the tested cookies is similar to that present in most of infant formulas, but differs significantly from that in human milk. Based on the results obtained, high oxidative stability of tested fats can be observed. The Ea values ranged from 86.22 to 116.13 kJ/mol; Z from 1.95 × 109 to 1.05 × 1013; and k values ranged from 5.70 × 10− 4 min− 1 at 100°C to 2.12 × 10− 1 min− 1 at 170°C.

The influence of trehalose–maltodextrin and lactose–maltodextrin matrices on thermal and sorption properties of spray-dried β-lactoglobulin–vitamin D3 complexes

In the study, the effect of lactose–maltodextrin and trehalose–maltodextrin matrices on the glass transition temperatures and moisture sorption characteristics of spray-dried β-lactoglobulin–vitamin D3 complexes was investigated. Incorporation of sugars into complexes can influence the thermal properties and moisture sorption characteristics of powders. The glass transition temperature as an important physiochemical parameter that determines the processing conditions, product quality and stability of the final product was studied with the use of modulated differential scanning calorimetry method. Moisture sorption isotherms, water activity and moisture content as parameters related to sorption properties, were also investigated. Additionally, particle size, wettability and insolubility index were studied to characterise newly synthesized products. For the samples tested, two well-separated glass transitions were found. The dominant effect of maltodextrin on the glass transition temperatures was observed. An increase in the percentage of maltodextrin added resulted in increasing Tg value of studied complexes. At low water activity all powdered complexes showed typical sorption behaviour of food systems. Trehalose as a carbohydrate component of powdered complexes, in comparison to lactose, delayed the occurrence of crystallization.

L-nucleosides containing modified nucleobases.

The synthesis of base modified l-nucleosides is described with pyrrolo[2,3-d]pyrimidines, pyrazolo[3,4-d)pyrimidines, benzimidazoles and imidazo[1,2-a]-s-triazines as nucleobases. The conformation of the nucleosides is studied and the antiviral activity is evaluated.

Effect of composition and drying method on glass transition temperature, water sorption characteristics and surface morphology of newly designed β-lactoglobulin/retinyl palmitate/disaccharides systems

In the study, MDSC method was used to evaluate thermal properties of β-lactoglobulin–retinyl palmitate products enriched in disaccharides. Additionally, sorption behavior of powders was determined to define their stability. The obtained powders were also examined and visualized with scanning electron microscopy to find the relationship between food processing conditions and morphological changes in products. For the samples tested, a single glass transition was observed. The results have shown the impact of the composition of studied samples on the glass transition temperatures. The carbohydrate- β-lactoglobulin systems were characterized by higher Tg values than disaccharides alone. At low water activity, all powdered complexes showed typical sorption behavior of food systems with the sigmoidal shape of the curve. The present study has shown that spray-dried and freeze-dried powdered products with lactose or trehalose have different time-dependent crystallization behavior. Trehalose as a carbohydrate component of samples, in comparison with lactose, delayed the occurrence of crystallization. The obtained images presented the dependence of the shape of the particles on the drying method used. Spray-dried powders were characterized by a spherical or close to spherical structure with the surface of larger particles often deformed. In the case of freeze-dried particles, irregular structures were observed.

Microwave-assisted synthesis of O'-adamantylated uracil-derived nucleosides.

Abstract Microwave-induced synthesis of O′-adamantyl derivatives of AZT, thymidine, 2′-deoxyuridine and uridine was investigated. Contrary to heterocyclus adamantylation of uracil and uridine in trifluoroacetic acid, the microwave-induced reaction provided sugar-substituted compounds.

Synthesis and Antimycobacterial and Antiprotozoal Activities of Some Novel Nitrobenzylated Heterocycles

A series of N-, S-, and O-mononitro- and dinitrobenzyl derivatives of heterocycles was synthesized by alkylation of heterocyclic bases with the respective nitrobenzyl chlorides. Of the newly synthesized compounds, dinitrobenzylsulfanyl derivatives of 1-methyl-2-mercaptoimidazole (2c) and of 5-nitro- and 5,6-dichloro-2-mercaptobenzimidazole (8b and 8c, and 8e and 8f, respectively) showed considerable antimycobacterial activity. On a molar basis, nine of the novel compounds showed also a considerably higher antiprotozoal efficacy than metronidazole that reduced T. hominis viability to 73.5% at 8 μg/ml.