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排序方式: 共有1707条查询结果,搜索用时 15 毫秒
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Anna Stasiowicz Natalia Rosiak Ewa Tykarska Maciej Kozak Jacek Jenczyk Piotr Szulc Joanna Kobus-Cisowska Kornelia Lewandowska Anita Paziska Wojciech Paziski Judyta Cielecka-Piontek 《International journal of molecular sciences》2021,22(8)
Piperine is an alkaloid that has extensive pharmacological activity and impacts other active substances bioavailability due to inhibition of CYP450 enzymes, stimulation of amino acid transporters and P-glycoprotein inhibition. Low solubility and the associated low bioavailability of piperine limit its potential. The combination of piperine with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) causes a significant increase in its solubility and, consequently, an increase in permeability through gastrointestinal tract membranes and the blood–brain barrier. X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) were used to characterize interactions between piperine and HP-β-CD. The observed physicochemical changes should be combined with the process of piperine and CD system formation. Importantly, with an increase in solubility and permeability of piperine as a result of interaction with CD, it was proven to maintain its biological activity concerning the antioxidant potential (2,2-diphenyl-1-picryl-hydrazyl-hydrate assay), inhibition of enzymes essential for the inflammatory process and for neurodegenerative changes (hyaluronidase, acetylcholinesterase, butyrylcholinesterase). 相似文献
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Dr. Tomasz Ratajczyk Prof. Dr. Gerd Buntkowsky Dr. Torsten Gutmann Dr. Bartłomiej Fedorczyk Dr. Adam Mames Dr. Mariusz Pietrzak Zuzanna Puzio Piotr Grzegorz Szkudlarek 《Chembiochem : a European journal of chemical biology》2021,22(5):855-860
The biorelevant PyFALGEA oligopeptide ligand, which is selective towards the epidermal growth factor receptor (EGFR), has been successfully employed as a substrate in magnetic resonance signal amplification by reversible exchange (SABRE) experiments. It is demonstrated that PyFALGEA and the iridium catalyst IMes form a PyFALGEA:IMes molecular complex. The interaction between PyFALGEA:IMes and H2 results in a ternary SABRE complex. Selective 1D EXSY experiments reveal that this complex is labile, which is an essential condition for successful hyperpolarization by SABRE. Polarization transfer from parahydrogen to PyFALGEA is observed leading to significant enhancement of the 1H NMR signals of PyFALGEA. Different iridium catalysts and peptides are inspected to discuss the influence of their molecular structures on the efficiency of hyperpolarization. It is observed that PyFALGEA oligopeptide hyperpolarization is more efficient when an iridium catalyst with a sterically less demanding NHC ligand system such as IMesBn is employed. Experiments with shorter analogues of PyFALGEA, that is, PyLGEA and PyEA, show that the bulky phenylalanine from the PyFALGEA oligopeptide causes steric hindrance in the SABRE complex, which hampers hyperpolarization with IMes. Finally, a single-scan 1H NMR SABRE experiment of PyFALGEA with IMesBn revealed a unique pattern of NMR lines in the hydride region, which can be treated as a fingerprint of this important oligopeptide. 相似文献
5.
Teresa Glomb Benita Wiatrak Katarzyna Gbczak Tomasz Gbarowski Dorota Bodetko aneta Czynikowska Piotr
witek 《International journal of molecular sciences》2020,21(23)
Numerous studies have confirmed the coexistence of oxidative stress and inflammatory processes. Long-term inflammation and oxidative stress may significantly affect the initiation of the neoplastic transformation process. Here, we describe the synthesis of a new series of Mannich base-type hybrid compounds containing an arylpiperazine residue, 1,3,4-oxadiazole ring, and pyridothiazine-1,1-dioxide core. The synthesis was carried out with the hope that the hybridization of different pharmacophoric molecules would result in a synergistic effect on their anti-inflammatory activity, especially the ability to inhibit cyclooxygenase. The obtained compounds were investigated in terms of their potencies to inhibit cyclooxygenase COX-1 and COX-2 enzymes with the use of the colorimetric inhibitor screening assay. Their antioxidant and cytotoxic effect on normal human dermal fibroblasts (NHDF) was also studied. Strong COX-2 inhibitory activity was observed after the use of TG6 and, especially, TG4. The TG11 compound, as well as reference meloxicam, turned out to be a preferential COX-2 inhibitor. TG12 was, in turn, a non-selective COX inhibitor. A molecular docking study was performed to understand the binding interaction of compounds at the active site of cyclooxygenases. 相似文献
6.
Agnieszka J. Klemm Piotr Klemm Kazimierz Rozniakowski Tomasz W. Wojtatowicz 《Building and Environment》2002,37(12):1233-1240
This paper presents the results of the larger study into a potential application of laser radiation for the detection of phase transition processes in low temperatures occurring on the surface layers of cementitious materials. An attempt was made to identify relationships between the environmental conditions—temperature and air humidity, and the selected parameters of the reflected light. Onset of the condensation process and formation of water microdrops on the surface of the material leads to the phase displacement of individual laser rays, which are represented by different speckle images.
Although the analysis of parameters of the reflected light are very difficult in the case of porous materials because of highly developed roughness of the surface structure it has been proved that a dynamic study of the phase transition phenomena can be successfully carried out without mechanical intervention. 相似文献
7.
Agnieszka J Klemm Piotr Klemm Kazimierz Rozniakowski Tomasz W Wojtatowicz 《Building and Environment》2002,37(12):1221-1232
This paper present the results of the investigation into a potential application of laser radiation for the detection of phase transition processes occurring on the surface layers of porous materials. An attempt was made to discuss in the approximation equations, the relationships between coefficients of the reflected light, the temperature and humidity of the surrounding environment. Laser light reflected from the porous surface carries information about the roughness of the structure. The presence of water microdrop on the surface of the porous material, as a result of condensation and thus a phase transition, leads to the phase displacement of individual rays, which is represented by different images. Therefore, a comprehensive analysis of the reflected light parameters allows a dynamic study of the phase transition phenomena without mechanical intervention. 相似文献
8.
Piotr Furma
ski 《International Journal of Heat and Mass Transfer》1994,37(18):2993-3002
A mixture theory based on the ensemble-averaging technique is proposed for studying the thermal behaviour of heterogeneous media. Balance equations with partial heat fluxes and interaction terms are introduced for a two-component medium. Relations between these quantities and the ensemble-averaged (mean) temperatures of separate components are derived. The limits of application of widely used postulates of proportionality of the interaction term of difference in mean temperature of components is discussed. The effective conductivities of components in the mixture and the interaction coefficient are introduced and related to the so-called microstructure functions, which are functions of the microgeometry of the medium and the thermal properties of its components. Examples of the application of the theory to the calculation of the mean properties of a heterogeneous medium are presented. 相似文献
9.
Renata Gruszka Krzysztof Zakrzewski Pawe Piotr Liberski Magdalena Zakrzewska 《International journal of molecular sciences》2021,22(2)
Numerous molecular factors disrupt the correctness of the cell cycle process leading to the development of cancer due to increased cell proliferation. Among known causative factors of such process is abnormal gene expression. Nowadays in the light of current knowledge such alterations are frequently considered in the context of mRNA–miRNA correlation. One of the molecular factors with potential value in tumorigenesis is the feedback loop between MYC and E2F genes in which miR-17-5p and miR-20a from the miR-17-92 cluster are involved. The current literature shows that overexpression of the members of the OncomiR-1 are involved in the development of many solid tumors. In the present work, we investigated the expression of components of the MYC/E2F/miR-17-92 network and their closely related elements including members of MYC and E2F families and miRNAs from two paralogs of miR-17-92: miR-106b-25 and miR-106a-363, in the most common brain tumors of childhood, pilocytic astrocytoma (PA), WHO grade 1; ependymoma (EP), WHO grade 2; and medulloblastoma (MB), WHO grade 4. We showed that the highest gene expression was observed in the MYC family for MYCN and in the E2F family for E2F2. Positive correlation was observed between the gene expression and tumor grade and type, with the highest expression being noted for medulloblastomas, followed by ependymomas, and the lowest for pilocytic astrocytomas. Most members of miR-17-92, miR-106a-363 and miR-106b-25 clusters were upregulated and the highest expression was noted for miR-18a and miR-18b. The rest of the miRNAs, including miR-19a, miR-92a, miR-106a, miR-93, or miR-25 also showed high values. miR-17-5p, miR-20a obtained a high level of expression in medulloblastomas and ependymomas, while close to the control in the pilocytic astrocytoma samples. miRNA expression also depended on tumor grade and histology. 相似文献
10.
Anna Iwaniak Damir Mogut Piotr Minkiewicz Justyna ulewska Magorzata Darewicz 《International journal of molecular sciences》2021,22(6)
In silico and in vitro methods were used to analyze ACE- and DPP-IV-inhibiting potential of Gouda cheese with a modified content of β-casein. Firstly, the BIOPEP-UWM database was used to predict the presence of ACE and DPP-IV inhibitors in casein sequences. Then, the following Gouda cheeses were produced: with decreased, increased, and normative content of β-casein after 1 and 60 days of ripening each (six variants in total). Finally, determination of the ACE/DPP-IV-inhibitory activity and the identification of peptides in respective Gouda-derived water-soluble extracts were carried out. The identification analyses were supported with in silico calculations, i.e., heatmaps and quantitative parameters. All Gouda variants exhibited comparable ACE inhibition, whereas DPP-IV inhibition was more diversified among the samples. The samples derived from Gouda with the increased content of β-casein (both stages of ripening) had the highest DPP-IV-inhibiting potency compared to the same samples measured for ACE inhibition. Regardless of the results concerning ACE and DPP-IV inhibition among the cheese samples, the heatmap showed that the latter bioactivity was predominant in all Gouda variants, presumably because it was based on the qualitative approach (i.e., peptide presence in the sample). Our heatmap did not include the bioactivity of a single peptide as well as its quantity in the sample. In turn, the quantitative parameters showed that the best sources of ACE/DPP-IV inhibitors were all Gouda-derived extracts obtained after 60 days of the ripening. Although our protocol was efficient in showing some regularities among Gouda cheese variants, in vivo studies are recommended for more extensive investigations of this subject. 相似文献