摘要 :
Two groups of natural products, sphydrofuran (1) and its furan derivative (2) and secosyrins 1 and 2(3a, 3b) and syributins 1 and 2(4a, 4b), were synthesized from one precursor (6), which was realized starting from 3-tri-n-butylst...
展开
Two groups of natural products, sphydrofuran (1) and its furan derivative (2) and secosyrins 1 and 2(3a, 3b) and syributins 1 and 2(4a, 4b), were synthesized from one precursor (6), which was realized starting from 3-tri-n-butylstannylfuran or 3-bromofuran.
收起
摘要 :
Alisma canaliculatum is a herb commonly used in traditional Korean medicine, and has been shown in scientific studies to have antitumor, diuretic hepatoprotective, and antibacterial effects. Recently, the anti-osteoclastogenesis o...
展开
Alisma canaliculatum is a herb commonly used in traditional Korean medicine, and has been shown in scientific studies to have antitumor, diuretic hepatoprotective, and antibacterial effects. Recently, the anti-osteoclastogenesis of alisol A 24-acetate from Alisma canaliculatum was investigated in vitro. However, the influence of alisol A 24-acetate on osteoporosis in animals has not been investigated. The present study was undertaken to investigate the anti-osteoporotic effect of alisol A 24-acetate on bone mass in ovariectomized (OVX) mice and to identify the mechanism responsible for its effects. OVX mice were treated daily with 0.5 or 2 μg/g of alisol A 24-acetate for a period of six weeks. It was found that these administrations significantly suppressed osteoporosis in OVX mice and improved bone morphometric parameters. The serum estradiol, bone alkaline phosphatase levels, regulatory T/Th17 cell numbers were significantly increased by alisol A 24-acetate as compared with untreated OVX mice. In addition, TRAP activity was inhibited by alisol A 24-acetate in OVX mice. These results suggest alisol A 24-acetate effectively prevents bone loss in OVX mice, and that it can be considered a potential therapeutic for the treatment of postmenopausal osteoporosis.
收起
摘要 :
Computational methods are well-established tools in the drug discovery process and can be employed for a variety of tasks. Common applications include lead identification and scaffold hopping, as well as lead optimization by struc...
展开
Computational methods are well-established tools in the drug discovery process and can be employed for a variety of tasks. Common applications include lead identification and scaffold hopping, as well as lead optimization by structure-activity relationship analysis and selectivity profiling. In addition, compound-target interactions associated with potentially harmful effects can be identified and investigated. This review focuses on pharmacophore-based virtual screening campaigns specifically addressing the target class of hydroxysteroid dehydrogenases. Many members of this enzyme family are associated with specific pathological conditions, and pharmacological modulation of their activity may represent promising therapeutic strategies. On the other hand, unintended interference with their biological functions, e.g., upon inhibition by xenobiotics, can disrupt steroid hormone-mediated effects, thereby contributing to the development and progression of major diseases. Besides a general introduction to pharmacophore modeling and pharmacophore-based virtual screening, exemplary case studies from the field of short-chain dehydrogenase/reductase (SDR) research are presented. These success stories highlight the suitability of pharmacophore modeling for the various application fields and suggest its application also in futures studies.
收起
摘要 :
Yan73, a teinturier (dyer) grape variety in China, is one of the few Vitis vinifera cultivars with red-coloured berry flesh. To examine the tissue-specific expression of genes associated with berry colour in Yan73, we analysed the...
展开
Yan73, a teinturier (dyer) grape variety in China, is one of the few Vitis vinifera cultivars with red-coloured berry flesh. To examine the tissue-specific expression of genes associated with berry colour in Yan73, we analysed the differential accumulation of anthocyanins in the skin and flesh tissues of two red-skinned grape varieties with either red (Yan73) or white flesh (Muscat Hamburg) based on HPLC-MS analysis, as well as the differential expression of 18 anthocyanin biosynthesis genes in both varieties by quantitative RT-PCR. The results revealed that the transcripts of GST, OMT, AM3, CHS3, UFGT, MYBA1, F3′5′H, F3H1 and LDOX were barely detectable in the white flesh of Muscat Hamburg. In particular, GST, OMT, AM3, CHS3 and F3H1 showed approximately 50-fold downregulation in the white flesh of Muscat Hamburg compared to the red flesh of Yan73. A correlation analysis between the accumulation of different types of anthocyanins and gene expression indicated that the cumulative expression of GST, F3′5′H, LDOX and MYBA1 was more closely associated with the acylated anthocyanins and the 3′5′-OH anthocyanins, while OMT and AM3 were more closely associated with the total anthocyanins and methoxylated anthocyanins. Therefore, the transcripts of OMT, AM3, GST, F3′5′H, LDOX and MYBA1 explained most of the variation in the amount and composition of anthocyanins in skin and flesh of Yan73. The data suggest that the specific localization of anthocyanins in the flesh tissue of Yan73 is most likely due to the tissue-specific expression of OMT, AM3, GST, F3′5′H, LDOX and MYBA1 in the flesh.
收起
摘要 :
Proteostasis are integrated biological pathways within cells that control synthesis, folding, trafficking and degradation of proteins. The absence of cell division makes brain proteostasis susceptible to age-related changes and ne...
展开
Proteostasis are integrated biological pathways within cells that control synthesis, folding, trafficking and degradation of proteins. The absence of cell division makes brain proteostasis susceptible to age-related changes and neurodegeneration. Two key processes involved in sustaining normal brain proteostasis are the unfolded protein response and autophagy. Alzheimer’s disease (AD), Parkinson’s disease (PD) and prion diseases (PrDs) have different clinical manifestations of neurodegeneration, however, all share an accumulation of misfolded pathological proteins associated with perturbations in unfolded protein response and macroautophagy. While both the unfolded protein response and macroautophagy play an important role in the prevention and attenuation of AD and PD progression, only macroautophagy seems to play an important role in the development of PrDs. Macroautophagy and unfolded protein response can be modulated by pharmacological interventions. However, further research is necessary to better understand the regulatory pathways of both processes in health and neurodegeneration to be able to develop new therapeutic interventions.
收起
摘要 :
Twenty-two 7-fluoro (or 8-methoxy)-4-anilinoquinolines compounds were designed and synthesized as potentially potent and selective antitumor inhibitors. All the prepared compounds were evaluated for their in vitro antiproliferativ...
展开
Twenty-two 7-fluoro (or 8-methoxy)-4-anilinoquinolines compounds were designed and synthesized as potentially potent and selective antitumor inhibitors. All the prepared compounds were evaluated for their in vitro antiproliferative activities against the HeLa and BGC823 cell lines. Ten compounds (1a–g; 2c; 2e and 2i) exhibited excellent antitumor activity superior to that of gefitinib. Among the ten compounds; seven (1a–c; 1e–1g and 2i) displayed excellent selectivity for BGC823 cells. In particular; 1f and 2i exhibited potent cytotoxic activities against HeLa cells and BGC823 cells with better IC50 values than gefitinib.
收起
摘要 :
Oxime derivatives are easily made, are non-hazardous and have long shelf lives. They contain weak N–O bonds that undergo homolytic scission, on appropriate thermal or photochemical stimulus, to initially release a pair of N- and O...
展开
Oxime derivatives are easily made, are non-hazardous and have long shelf lives. They contain weak N–O bonds that undergo homolytic scission, on appropriate thermal or photochemical stimulus, to initially release a pair of N- and O-centred radicals. This article reviews the use of these precursors for studying the structures, reactions and kinetics of the released radicals. Two classes have been exploited for radical generation; one comprises carbonyl oximes, principally oxime esters and amides, and the second comprises oxime ethers. Both classes release an iminyl radical together with an equal amount of a second oxygen-centred radical. The O-centred radicals derived from carbonyl oximes decarboxylate giving access to a variety of carbon-centred and nitrogen-centred species. Methods developed for homolytically dissociating the oxime derivatives include UV irradiation, conventional thermal and microwave heating. Photoredox catalytic methods succeed well with specially functionalised oximes and this aspect is also reviewed. Attention is also drawn to the key contributions made by EPR spectroscopy, aided by DFT computations, in elucidating the structures and dynamics of the transient intermediates.
收起
摘要 :
A study was undertaken of the solvolysis of pivaloyl triflate in a variety of ionic liquid:alcohol solvent mixtures. The solvolysis is a kΔ process (i.e., a process in which ionization occurs with rearrangement), and the resulting...
展开
A study was undertaken of the solvolysis of pivaloyl triflate in a variety of ionic liquid:alcohol solvent mixtures. The solvolysis is a kΔ process (i.e., a process in which ionization occurs with rearrangement), and the resulting rearranged carbocation intermediate reacts with the alcohol cosolvent via two competing pathways: nucleophilic attack or elimination of a proton. Five different ionic liquids and three different alcohol cosolvents were investigated to give a total of fifteen dual solvent systems. 1H-NMR analysis was used to determine relative amounts of elimination and substitution products. It was found, not surprisingly, that increasing the bulkiness of alcohol cosolvent led to increased elimination product. The change in the amount of elimination product with increasing ionic liquid concentration, however, varied greatly between ionic liquids. These differences correlate strongly, though not completely, to the Kamlet–Taft solvatochromic parameters of the hydrogen bond donating and accepting ability of the solvent systems. An additional factor playing into these differences is the bulkiness of the ionic liquid anion.
收起
摘要 :
The mono ortho-bromination of phenolic building blocks by NBS has been achieved in short reaction times (15–20 min) using ACS-grade methanol as a solvent. The reactions can be conducted on phenol, naphthol and biphenol substrates,...
展开
The mono ortho-bromination of phenolic building blocks by NBS has been achieved in short reaction times (15–20 min) using ACS-grade methanol as a solvent. The reactions can be conducted on phenol, naphthol and biphenol substrates, giving yields of >86% on gram scale. Excellent selectivity for the desired mono ortho-brominated products is achieved in the presence of 10 mol % para-TsOH, and the reaction is shown to be tolerant of a range of substituents, including CH3, F, and NHBoc.
收起
摘要 :
the gas phase reactions of fluoride with 3-chlorocyclohexene and 3-fluorocyclohexene habe been investigated with ab initio calculations up to the MP2/6-31+G** level. Transition states were located for 1,4-eliminations and 1,2-elim...
展开
the gas phase reactions of fluoride with 3-chlorocyclohexene and 3-fluorocyclohexene habe been investigated with ab initio calculations up to the MP2/6-31+G** level. Transition states were located for 1,4-eliminations and 1,2-eliminations as well as S_N2' substitutions. For each rection, a variety of stereochemical outcomes was explored. For both systems, the preferred pathway is an anti 1,4-elimination, but syn 1,4-eliminations and anti 1,2-eliminations have transition states that are nearly as stable.
收起
