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261.
An electrochemical biosensor with a new bioorganometallic approach for the detection of human immunodeficiency virus (HIV) type 1 protease (HIV-1 PR) using surface-bound ferrocenoyl (Fc)-pepstatin conjugates is presented. 相似文献
262.
Behery FA Naeem ZE Maatooq GT Amer MM Wen ZH Sheu JH Ahmed AF 《Chemical & pharmaceutical bulletin》2007,55(8):1264-1266
The novel natural product juncutol (1), 1,4,7-trimethyl-8,9-dihydro-4H-cyclopenta[def]phenanthrene-2,6-diol, along with the three related metabolites juncusol (2), dehydrojuncusol (3), and 6-hydroxymethyl-1-methyl-5-vinyl-9,10-dihydrophenanthrene-2-ol (4), were isolated from the rhizomes of Juncus acutus L. (Juncaceae) growing in Egypt. The structural identity of 1 was determined on the basis of spectroscopic analyses, including 2D NMR spectroscopy. The inhibitory effect of these natural products on the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide-stimulated RAW264.7 macrophage cells was determined for the first time. The unprecedented symmetrical compound juncutol (1) was found to be the most potent inhibitor against the induction of the proinflammatory iNOS protein. 相似文献
263.
El-Halawany AM Chung MH Nakamura N Ma CM Nishihara T Hattori M 《Chemical & pharmaceutical bulletin》2007,55(10):1476-1482
Through an estrogenic activity bioassay-guided fractionation of the 70% ethanolic extract of Cassia tora seeds two new phenolic triglucosides, torachrysone 8-O-[beta-D-glucopyranosyl(1-->3)-O-beta-D-glucopyranosyl(1-->6)-O-beta-D-glucopyranoside] (1) and toralactone 9-O-[beta-D-glucopyranosyl-(1-->3)-O-beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranoside] (2), along with seven known compounds were isolated. The structures of the new compounds were elucidated on the basis of spectroscopic and chemical evidence. The estrogenic activity of the fractions and the isolated compounds were investigated using the estrogen-dependent proliferation of MCF-7 cells. In addition, the yeast two hybrid assay expressing estrogen receptor alpha (ERalpha) and beta (ERbeta) and the ERalpha competitor screening assay (ligand binding screen) were used to verify the binding affinities of the isolated compounds to ER. Furthermore, a naringinase pre-treatment of the 70% alcoholic extract of Cassia tora seeds resulted in a significant increase in its estrogenic activity. From the naringinase pre-treated extract six compounds were isolated, among which 6-hydroxymusizin and aurantio-obtusin showed the most potent estrogenic activity, while torachrysone, rubrofusarin and toralactone showed a significant anti-estrogenic activity. Finally, the structure requirements responsible for the estrogenic activity of the isolated compounds were studied by investigating the activity of several synthetic compounds and chemically modifying the isolated compounds. The basic nucleus 1,3,8-trihyroxynaphthalene (T(3)HN) was found to play a principal role in the binding affinity of these compounds to ER. 相似文献
264.
Ahmad S. Shawali Magda A. Abdallah Mosselhi A. N. Mosselhi Mahmoud S. Elewa 《Journal of heterocyclic chemistry》2007,44(2):285-288
Reactions of 4‐arylhydrazono‐2‐methylthio‐imidazolin‐5(1H)‐one 3 with various hydrazonoyl halides 1 proved to be site‐selective and yielded the respective imidazo[2,1‐c][1,2,4]triazole derivatives 8 . The structure of the latter was elucidated by X‐ray analysis and the mechanism of the studied reactions was discussed. 相似文献
265.
Hamdoon A. Mohammed Hussein M. Eldeeb Riaz A. Khan Mohsen S. Al-Omar Salman A. A. Mohammed Mohammed S. M. Sajid Mohamed S. A. Aly Adel M. Ahmad Ahmed A. H. Abdellatif Safaa Yehia Eid Mahmoud Zaki El-Readi 《Molecules (Basel, Switzerland)》2021,26(19)
Sage, Salvia officinalis L., is used worldwide as an aromatic herb for culinary purposes as well as a traditional medicinal agent for various ailments. Current investigations exhibited the effects of extended dryings of the herb on the yields, composition, oil quality, and hepatoprotective as well as anti-cancer biological activities of the hydrodistillation-obtained essential oils from the aerial parts of the plant. The essential oils’ yields, compositions, and biological activities levels of the fresh and differently timed and room-temperature dried herbs differed significantly. The lowest yields of the essential oil were obtained from the fresh herbs (FH, 631 mg, 0.16%), while the highest yield was obtained from the two-week dried herbs (2WDH, 1102 mg, 0.28%). A notable decrease in monoterpenes, with increment in the sesquiterpene constituents, was observed for the FH-based essential oil as compared to all the other batches of the essential oils obtained from the different-timed dried herbs. Additionally, characteristic chemotypic constituents of sage, i.e., α-pinene, camphene, β-pinene, myrcene, 1, 8-cineole, α-thujone, and camphor, were present in significantly higher proportions in all the dried herbs’ essential oils as compared to the FH-based essential oil. The in vivo hepatoprotective activity demonstrated significant reductions in the levels of AST, ALT, and ALP, as well as a significant increase in the total protein (p < 0.05) contents level, as compared to the acetaminophen (AAP) administered experimental group of rats. A significant reduction (p < 0.05) in the ALT level was demonstrated by the 4WDH-based essential oil in comparison to the FH-based essential oil. The levels of creatinine, cholesterol, and triglycerides were reduced (p < 0.05) in the pre-treated rats by the essential oil batches, with non-significant differences found among them as a result of the herbs dryings based oils. A notable increase in the viability of the cells, and total antioxidant capacity (TAOxC) levels, together with the reduction in malondialdehyde (MDA) levels were observed by the essential oils obtained from all the batches as compared with the AAP-treated cell-lines, HepG-2, HeLa, and MCF-7, that indicated the in vitro hepatoprotective effects of the sage essential oils. However, significant improvements in the in vivo and in vitro hepatoprotective activities with the 4WDH-based oil, as compared to all other essential oil-batches and silymarin standard demonstrated the beneficial effects of the drying protocol for the herb for its medicinal purposes. 相似文献
266.
Caroline Piffet Bénédicte Vertruyen Frédéric Hatert Rudi Cloots Frédéric Boschini Abdelfattah Mahmoud 《Journal of Energy Chemistry》2022,(2):210-218
Na2Ti3O7 has attracted much attention in the field of anode materials for Na-ion batteries thanks to its non-toxicity and very low working potential of 0.3 V vs Na0/Na+.Building a clearer picture of its formation from cheap Na2CO3 and TiO2 starting materials is therefore of obvious interest.Here,we report new insights from an in-situ high temperature X-ray diffraction study conducted from room temperature to 800°C,complemented by ex-situ characterizations.We were thereby able to position the previously reported Na4Ti5O12 and Na2Ti6O13 intermediate phases in a reaction scheme involving three successive steps and temperature ranges.Shifts and/or broadening of a subset of the Na2Ti6O13 reflections suggested a combination of intra-layer disorder with the well-established ordering of successive layers.This in-situ study was carried out on reproducible mixtures of Na2CO3 and TiO2 in 1:3 molar ratio prepared by spraydrying of mixed aqueous suspensions.Single-phase Na2Ti3O7 was obtained after only 8 h at 800°C in air,instead of a minimum of 20 h for a conventional solid-state route using the same precursors.Microstructure analysis revealed~15 mm diameter granules made up from rectangular rods of a fewmm length presenting electrochemical properties in line with expectations.In the absence of grinding or formation of intimate composites with conductive carbon,the specific capacity of 137 m Ah/g at C/5 decreased at higher rates. 相似文献
267.
Ahmed A. Al-Karmalawy Mai M. Farid Ahmed Mostafa Alia Y. Ragheb Sara H. Mahmoud Mahmoud Shehata Noura M. Abo Shama Mohamed GabAllah Gomaa Mostafa-Hedeab Mona M. Marzouk 《Molecules (Basel, Switzerland)》2021,26(21)
Flavonoids are important secondary plant metabolites that have been studied for a long time for their therapeutic potential in inflammatory diseases because of their cytokine-modulatory effects. Five flavonoid aglycones were isolated and identified from the hydrolyzed aqueous methanol extracts of Anastatica hierochuntica L., Citrus reticulata Blanco, and Kickxia aegyptiaca (L.) Nabelek. They were identified as taxifolin (1), pectolinarigenin (2), tangeretin (3), gardenin B (4), and hispidulin (5). These structures were elucidated based on chromatographic and spectral analysis. In this study, molecular docking studies were carried out for the isolated and identified compounds against SARS-CoV-2 main protease (Mpro) compared to the co-crystallized inhibitor of SARS-CoV-2 Mpro (α-ketoamide inhibitor (KI), IC50 = 66.72 µg/mL) as a reference standard. Moreover, in vitro screening against SARS-CoV-2 was evaluated. Compounds 2 and 3 showed the highest virus inhibition with IC50 12.4 and 2.5 µg/mL, respectively. Our findings recommend further advanced in vitro and in vivo studies of the examined isolated flavonoids, especially pectolinarigenin (2), tangeretin (3), and gardenin B (4), either alone or in combination with each other to identify a promising lead to target SARS-CoV-2 effectively. This is the first report of the activity of these compounds against SARS-CoV-2. 相似文献
268.
Mahmoud G. Metwally Abdelaziz H. Benhawy Reda M. Khalifa Rasha M. El Nashar Marek Trojanowicz 《Molecules (Basel, Switzerland)》2021,26(21)
The increase of the global population and shortage of renewable water resources urges the development of possible remedies to improve the quality and reusability of waste and contaminated water supplies. Different water pollutants, such as heavy metals, dyes, pesticides, endocrine disrupting compounds (EDCs), and pharmaceuticals, are produced through continuous technical and industrial developments that are emerging with the increasing population. Molecularly imprinted polymers (MIPs) represent a class of synthetic receptors that can be produced from different types of polymerization reactions between a target template and functional monomer(s), having functional groups specifically interacting with the template; such interactions can be tailored according to the purpose of designing the polymer and based on the nature of the target compounds. The removal of the template using suitable knocking out agents renders a recognition cavity that can specifically rebind to the target template which is the main mechanism of the applicability of MIPs in electrochemical sensors and as solid phase extraction sorbents. MIPs have unique properties in terms of stability, selectivity, and resistance to acids and bases besides being of low cost and simple to prepare; thus, they are excellent materials to be used for water analysis. The current review represents the different applications of MIPs in the past five years for the detection of different classes of water and wastewater contaminants and possible approaches for future applications. 相似文献
269.
Creep tests under the effect of cyclic stress reduction were conducted to Al‐16 wt%Ag and Al‐16 wt%Ag‐0.1 wt%Zr alloys aged at 548 and 673 K. The steady state creep rate was found to be higher under cyclic stress reduction condition than that under static creep condition for the same maximum stress. An expression for the temperature dependence of the threshold stress for cyclic creep acceleration is offered. Cyclic creep acceleration is interpreted using the dislocation cross‐slip model. TEM investigations confirmed that the addition of Zr to Al‐Ag alloy accelerates the formation and coarsening of γ′ and γ‐phases. The mean value of activation energy for both alloys aged at 548 K was found to be 35±0.3 kJ/mol, and 58±0.4 kJ/mol for alloys aged at 673 K. 相似文献
270.
Marco Garzotti Luca Rovatti Mahmoud Hamdan 《Rapid communications in mass spectrometry : RCM》1998,12(8):484-488
Adduction between acrylamide and cysteine residues is a post-translational modification associated with proteins separated by gel electrophoresis. In the present article, three model peptides containing 2–4 cysteine residues were reduced with dithiothreitol, incubated with acrylamide monomers and examined by on-line liquid chromatography coupled to electrospray tandem mass spectrometry. Each of the solutions examined in this work revealed the presence of four distinct components: the free peptide, two different peptide–acrylamide 1:1 adducts involving two cysteine residues at different positions within the same sequence, and peptide–acrylamide 1:2 adducts. The use of liquid chromatography allowed the separation of components which differed only by the site of complexation of acrylamide, while the application of tandem mass spectrometry furnished reliable sequencing information permitting the identification of most cysteine residues involved in such complexation. © 1998 John Wiley & Sons, Ltd. 相似文献