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81.
Bartomiej Piasecki Anna Biernasiuk Adrianna Skiba Krystyna Skalicka-Wo
niak Agnieszka Ludwiczuk 《Molecules (Basel, Switzerland)》2021,26(24)
Many of the essential oils obtained from medicinal plants possess proven antimicrobial activity and are suitable for medicinal purposes and applications in the food industry. The aim of the present work was the chemical analysis of 19 essential oils (EOs) from seven different Cymbopogon species (C. nardus, C. citratus, C winterianus, C. flexuosus, C. schoenanthus, C. martinii, C. giganteus). Five different chemotypes were established by GC/MS and TLC assay. The EOs, as well as some reference compounds, i.e., citronellol, geraniol and citral (neral + geranial), were also tested for their antimicrobial and antibiofilm activity against methicillin-resistant Staphylococcus aureus (MRSA) by the microdilution method and direct bioautography. The toxicity of EOs was evaluated by Danio rerio ‘Zebrafish’ model assay. All examined EOs showed moderate to high activity against MRSA, with the highest activity noted for C. flexuosus—lemongrass essential oil, both in microdilution and direct autobiography method. Significant difference in the toxicity of the examined EOs was also detected. 相似文献
82.
Paulina Grocholska Andrzej Konieczny Zuzanna Ka
mierczak Krystyna Dbrowska Karolina Panek-Laszczyska Marlena Kak Wojciech Witkiewicz Zbigniew Szewczuk Remigiusz Bchor 《Molecules (Basel, Switzerland)》2021,26(23)
Early detection of any preeclampsia biomarkers may lower the risk of mortality, both for a mother and a child. Our study focuses on techniques for preeclampsia biomarker identification by comparing the results of a method using liquid chromatography mass spectrometry in multiple reaction monitoring mode (LC-MS/MS) with those by the enzyme-linked immunosorbent assay (ELISA) test, as well as by comparing the obtained results with clinical data. In the proposed LC-MS/MS method a tryptic digest peptide charge derivatization strategy was used as a tool for sensitive detection of podocin, i.e., a previously discovered preeclampsia biomarker present in urine samples from pregnant women. Urine samples from pregnant women with diagnosed preeclampsia were collected at different stages of pregnancy and from healthy subjects, and then were analyzed by ELISA test and the proposed method with LC-MS/MS. Charge derivatization of the ε amino group of C-terminal lysine residues in tryptic digests by 2,4,6-triphenylpyrylium salt was performed to increase the ionization efficiency in the LC-MS/MS mode. Podocin was identified at the early stage of pregnancy, while its detection using an ELISA test was not possible. The protocol for urine sample preparation was optimized. Our results show that the proposed method by LC-MS/MS in combination with peptide charge derivatization, provides an ultrasensitive tool for diagnosis of preeclampsia, and provides earlier detection than a clinical diagnosis or ELISA test. The proposed solution may revolutionize medical diagnostics. 相似文献
83.
Magdalena Biesaga Elzbieta Stolarczyk Krystyna Pyrzyńska Marek Trojanowicz 《Analytical sciences》2002,18(2):151-154
The silica-based Fe(III)-protoporphyrin and Zn-tetraphenylporphyrin stationary phases were examined for the HPLC separation of anions. The retention of nine common inorganic anions as well as benzoate anion (BA) and its hydroxy analogues (HBA) was examined using tartrate, acetate, and succinate eluents. The retention factors of inorganic anions on the FeProP stationary phase were in the order Cl- < NO3- < ClO4- < I- < SCN- and for organic anions benzoate < p-hydroxybenzoate < m-hydoxybenzoate < o-hydroxybenzoate. The retention factors of organic anions examined for a ZnTPP column were in the order p-HBA < m-HBA < BA < o-HBA. 相似文献
84.
Carbon nanotubes and graphitized carbon are investigated as adsorbents for solid phase extraction of dicamba and 2,4,5-T,
two phenoxyalkanoic acid herbicides. These adsorbents have much greater adsorption capability than that of C18 bonded silica, which was also tested for comparison studies. The adsorption capacity increases remarkably at lower pH of
the sample solution. Freundlich isotherms were applied to analyze the data. Our studies suggest that carbon nanotubes have
great potential applications in environmental analysis. 相似文献
85.
Gas chromatographic analysis was performed on the products of thermal decomposition of polyvinyl chloride with particular attention on the identification of the obtained reaction products and the role of oxygen in the process. 相似文献
86.
Goldys EM Drozdowicz-Tomsia K Jinjun S Dosev D Kennedy IM Yatsunenko S Godlewski M 《Journal of the American Chemical Society》2006,128(45):14498-14505
Rare-earth-doped nanoparticles are promising materials for fluorescent labeling, as they are characterized by a high Stokes shift, narrow emission spectra, long lifetimes, minimized photobleaching, and low toxicity. We examined the structural and optical properties of europium-doped gadolinium oxide nanoparticles synthesized by the flame pyrolysis method, with specific emphasis on full spectral characterization and fluorescence kinetics. The emission-excitation characterization revealed the presence of predominantly monoclinic but also highly luminescent cubic phases with a prominent oxygen-to-europium charge-transfer band in the 230-260 nm range. A broad emission band in the visible region, corresponding to a similar band in undoped Gd(2)O(3), related to the matrix surface defects, was observed in time-gated spectroscopy of doped nanopowders. All of the examined nanopowders showed very short decay components, on the order of 2 ns, and much longer millisecond decay times characteristic of lanthanide ions. At intermediate times, on the order of 20-100 ns, a complex behavior of the decay was observed, indicative of progressive energy transfer to the lanthanide ion, which varied with different intrashell transitions. Structural characterization data by means of XRD measurements allowed for unambiguous determination of the Eu:Gd(2)O(3) crystallographic structure and cell dimensions to be consistent with a predominantly monoclinic phase. 相似文献
87.
Dr. Agnieszka Janiak Prof. Dr. Urszula Rychlewska Dr. Marcin Kwit Urszula Stępień Dr. Krystyna Gawrońska Prof. Dr. Jacek Gawroński 《Chemphyschem》2012,13(6):1500-1506
Stereoisomers of one of the most important organic compounds, tartaric acid, optically active and meso as well as the ester or amide derivatives, can show diverse structures related to the rotation around the three carbon–carbon bonds. This study determines the controlling factors for conformational changes of these molecules in vacuo, in solution, and in the crystalline state using DFT calculations, spectroscopic measurements, and X‐ray diffraction. All structural variations can be logically accounted for by the possibility of formation and breaking of hydrogen bonds between the hydroxy or amide donors and oxygen acceptors, among these the hydrogen bonds that close five‐membered rings being the most stable. These findings are useful in designing molecular and crystal structures of highly polar, polyfunctional, chiral compounds. 相似文献
88.
Here, we describe the reliable method for the detection and quantitation of a pheomelanin component in melanin pigments. Synthetic melanins with various contents of pheomelanin-type structural units were thermally degraded, and the multiple reaction monitoring mode was applied to detect the pheomelanin markers in the pyrolysates by GC/MS/MS. The method allowed the specific detection and quantitation of a pheomelanin component in melanin with the incorporation of pheomelanin-type units as low as 0.05%. Considering highly universal character of the pheomelanin markers, the method could be applied for structural studies of natural melanin pigments being mixtures of eumelanin and pheomelanin. 相似文献
89.
Coumarins are nowadays an important group of organic compounds from natural sources that are useful in a number of fields. Because they possess different pharmacological properties, finding the proper extraction conditions for their separation from plant matrices is a very important step. In this report Pressurized Liquid Extraction (PLE) under different temperature conditions and with different types of extraction solvents were tested. As a matrix, fruits of Heracleum leskowii have been used. A simple reverse phase high-performance liquid chromatographic method (RP-HPLC) coupled with a photodiode array detector (DAD) has been developed for separation and quantitative analysis of the main coumarins. Umbelliferone, xanthotoxin, angelicin, isopimpinellin, bergapten, imperatorin and isoimperatorin were investigated. Bergapten and imperatorin were dominant in almost all extracts in the range of 9.92 ± 0.02-20.93 ± 0.06 and 12.19 ± 0.98-19.07 ± 0.03 mg/100 g, respectively. Dichloromethane and methanol were chosen as the most proper suitable solvents for extraction of coumarins. By increasing the temperature the amount of extracted coumarins increases in petroleum ether and dichloromethane extracts. 相似文献
90.