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Potential Analysis - We study the quenched long time behaviour of the survival probability up to time t, $\mathbf {E}_{x}\left [e^{-{{\int }_{0}^{t}} V^{\omega }(X_{s})\mathrm {d}s}\right ],$ of a... 相似文献
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Pascal Wintergerst Kamil Witas Djawed Nauroozi Marie-Ann Schmid Ebru Dikmen Stefanie Tschierlei Sven Rau 《无机化学与普通化学杂志》2020,646(13):842-848
The synthesis of alkyne functionalized bipyridine ruthenium complexes are reported. The improved synthetic approach through application of stable protecting groups prevents formation of possible side products while facilitating purification. By applying copper-catalysed azide-alkyne cycloaddition reactions (CuAAC) pyrene units with flexible alkyl linkers are introduced at the periphery of the complex, opening up various applications including surface immobilization and DNA intercalation. All complexes are characterized structurally as well as photophysically, especially regarding the influence of the introduced alkyne and triazolyl substituents on their photophysical behavior. 相似文献
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Kamil Hoffmann Joanna Wiśniewska Anna Kaczmarek-Kędziera Joanna Wietrzyk 《Journal of Coordination Chemistry》2015,68(17-18):3193-3208
The reaction of silver acetate with cis-[PtI2(dbtp)2], where dbtp = 5,7-ditertbutyl-1,2,4-triazolo-[1,5-a]pyrimidine, yielded cis-[Pt(OOCCH3)2(dbtp)2]·dmf (1). The complex has been analyzed by multinuclear magnetic resonance (1H, 13C, 15N), IR, and Raman. The compound formed two rotamers in CDCl3 and its spatial structures have been optimized using computational calculation. It was found that head-to-tail rotamer (1a) is more stable than its head-to-head counterpart (1b). In vitro antiproliferative activity against four tumor cell lines (A549, T47D, FaDu, and A2780cis) revealed in all cases significant cytotoxicity (IC50 = 0.26–1.80 μM), possessing IC50 values at least fivefold lower than cisplatin, carboplatin, and oxaliplatin (except A2780cis). The remarkable in vitro activity against T47D and A2780cis suggested the ability to overcome cisplatin resistance in these types of tumor cells. In addition, in vitro toxicity was evaluated against BALB/3T3 and has shown that the lipophilic platinum(II) complex (1) inhibits cell proliferation weaker than cisplatin and oxaliplatin. Additionally, cis-[Pt(OOCCH3)2(dbtp)2]·dmf exhibited selective activity, in contrast to cisplatin or oxaliplatin. 相似文献
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Kanchan Bhardwaj Ana Sanches Silva Maria Atanassova Rohit Sharma Eugenie Nepovimova Kamil Musilek Ruchi Sharma Mousa A. Alghuthaymi Daljeet Singh Dhanjal Marcello Nicoletti Bechan Sharma Navneet Kumar Upadhyay Natlia Cruz-Martins Prerna Bhardwaj Kamil Ku
a 《Molecules (Basel, Switzerland)》2021,26(10)
Conifers have long been recognized for their therapeutic potential in different disorders. Alkaloids, terpenes and polyphenols are the most abundant naturally occurring phytochemicals in these plants. Here, we provide an overview of the phytochemistry and related commercial products obtained from conifers. The pharmacological actions of different phytochemicals present in conifers against bacterial and fungal infections, cancer, diabetes and cardiovascular diseases are also reviewed. Data obtained from experimental and clinical studies performed to date clearly underline that such compounds exert promising antioxidant effects, being able to inhibit cell damage, cancer growth, inflammation and the onset of neurodegenerative diseases. Therefore, an attempt has been made with the intent to highlight the importance of conifer-derived extracts for pharmacological purposes, with the support of relevant in vitro and in vivo experimental data. In short, this review comprehends the information published to date related to conifers’ phytochemicals and illustrates their potential role as drugs. 相似文献
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Aleksandra Dymek Jarosaw Widelski Krzysztof Kamil Wojtanowski Paulina Poszaj Rostyslav Zhuravchak Tomasz Mroczek 《Molecules (Basel, Switzerland)》2021,26(6)
Alkaloids of the Lycopodiaceae family are of great interest to researchers due to their numerous properties and wide applications in medicine. They play a very important role mainly due to their potent antioxidant, antidepressant effects and a reversible ability to inhibit acetylcholinesterase (AChE) enzyme activity. This property is of immense importance due to the growing problem of an increasing number of patients with neurodegenerative diseases in developed countries and a lack of effective and efficient treatment for them. Numerous studies have shown that Lycopodiaceae alkaloids are a rich source of AChE inhibitors. In the obtaining of new therapeutic phytochemicals from plant material, the extraction process and its efficiency is crucial. Therefore, the aim of this work was to optimize the conditions of modern PLE to obtain bioactive alkaloids from two Lycopodium species: L. clavatum L. and L. annotinum L. Five different solvents of different polarity were used for prepared plant extracts in order to compare the alkaloid content in and thereby effectiveness of the entire extraction. PLE parameters were used based on multiple studies conducted that gave the highest alkaloids recovery. Crude extracts were purified using solid-phase extraction (SPE) on Oasis HLB cartridge and examined by HPLC/ESI-QTOF–MS of the highly abundant alkaloids. To the best of our knowledge, this is the first time such high recoveries have been obtained for known Lycopodiaceae alkaloids. The best extraction results of alkaloid-lycopodine were detected in the dichloromethane extract from L. clavatum, where the yield exceeded 45%. The high recovery of annotinine above 40% presented in L. annotinum was noticed in dichloromethane and ethyl acetate extracts. Moreover, chromatograms were obtained with all isolated alkaloids and the best separation and quality of the bands in methanolic extracts. Interestingly, no alkaloid amounts were detected in cyclohexane extracts belonging to the non-polar solvent. These results could be helpful for understanding and optimizing the best conditions for isolating potent AChE inhibitors. 相似文献
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Kamil J. Kuder Magdalena Kotaska Katarzyna Szczepaska Kamil Mika David Reiner-Link Holger Stark Katarzyna Kie-Kononowicz 《Molecules (Basel, Switzerland)》2021,26(8)
In an attempt to find new dual acting histamine H3 receptor (H3R) ligands, we designed a series of compounds, structurally based on previously described in our group, a highly active and selective human histamine H3 receptor (hH3R) ligand KSK63. As a result, 15 obtained compounds show moderate hH3R affinity, the best being the compound 17 (hH3R Ki = 518 nM). Docking to the histamine H3R homology model revealed two possible binding modes, with key interactions retained in both cases. In an attempt to find possible dual acting ligands, selected compounds were tested for antioxidant properties. Compound 16 (hH3R Ki = 592 nM) showed the strongest antioxidant properties at the concentration of 10−4 mol/L. It significantly reduced the amount of free radicals presenting 50–60% of ascorbic acid activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, as well as showed antioxidative properties in the ferric reducing antioxidant power (FRAP) assay. Despite the yet unknown antioxidation mechanism and moderate hH3R affinity, 16 (QD13) constitutes a starting point for the search of potential dual acting H3R ligands-promising tools for the treatment of neurological disorders associated with increased neuronal oxidative stress. 相似文献
9.
Dr. Santiago Alonso-Gil Dr. Kamil Parkan Dr. Jakub Kaminský Dr. Radek Pohl Dr. Takatsugu Miyazaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(14):e202200148
The conformational changes in a sugar moiety along the hydrolytic pathway are key to understand the mechanism of glycoside hydrolases (GHs) and to design new inhibitors. The two predominant itineraries for mannosidases go via OS2→B2,5→1S5 and 3S1→3H4→1C4. For the CAZy family 92, the conformational itinerary was unknown. Published complexes of Bacteroides thetaiotaomicron GH92 catalyst with a S-glycoside and mannoimidazole indicate a 4C1→4H5/1S5→1S5 mechanism. However, as observed with the GH125 family, S-glycosides may not act always as good mimics of GH's natural substrate. Here we present a cooperative study between computations and experiments where our results predict the E5→B2,5/1S5→1S5 pathway for GH92 enzymes. Furthermore, we demonstrate the Michaelis complex mimicry of a new kind of C-disaccharides, whose biochemical applicability was still a chimera. 相似文献
10.
Marek Grzybowski Kamil Skonieczny Prof. Dr. Holger Butenschön Prof. Dr. Daniel T. Gryko 《Angewandte Chemie (International ed. in English)》2013,52(38):9900-9930
Does the dehydrogenative coupling of aromatic compounds mediated by AlCl3 at high temperatures and also by FeCl3, MoCl5, PIFA, or K3[Fe(CN)6] at room temperature proceed by the same mechanism in all cases? With the growing importance of the synthesis of aromatic compounds by double C? H activation to give various biaryl structures, this question becomes pressing. Since some of these reactions proceed only in the presence of non‐oxidizing Lewis acids and some only in the presence of certain oxidants, the authors venture the hypothesis that, depending on the electronic structure of the substrates and the nature of the “catalyst”, two different mechanisms can operate. One involves the intermediacy of a radical cation and the other the formation of a sigma complex between the acid and the substrate. The goal of this Review is to encourage further mechanistic studies hopefully leading to an in‐depth understanding of this phenomenon. 相似文献