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971.
In the search for novel anti-infectives from natural sources, fungi, in particular basidiomycetes, have proven to still harbor so much potential in terms of secondary metabolites diversity. There have been numerous reports on isolating numerous secondary metabolites from genus Laetiporus. This study reports on two new triterpenoids, laetiporins C and D, and four known triterpenes from the fruiting body of L. sulphureus. The structures of the isolated compounds were elucidated based on their 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data in combination with high-resolution electrospray mass spectrometric (HR-ESIMS) data. Laetiporin C exhibited weak antifungal activity against Mucor hiemalis. Furthermore, the compounds showed weak antiproliferative activity against the mouse fibroblast L929 and human cancer cell lines, including KB-3-1, A431, MCF-7, PC-3 and A549. 相似文献
972.
Atteeque Ahmed Aamer Saeed Omar M. Ali Zeinhom M. El-Bahy Pervaiz Ali Channar Asma Khurshid Arfa Tehzeeb Zaman Ashraf Hussain Raza Anwar Ul-Hamid Mubashir Hassan 《Molecules (Basel, Switzerland)》2021,26(23)
This article describes the design and synthesis of a series of novel amantadine-thiourea conjugates (3a–j) as Jack bean urease inhibitors. The synthesized hybrids were assayed for their in vitro urease inhibition. Accordingly, N-(adamantan-1-ylcarbamothioyl)octanamide (3j) possessing a 7-carbon alkyl chain showed excellent activity with IC50 value 0.0085 ± 0.0011 µM indicating that the long alkyl chain plays a vital role in enzyme inhibition. Whilst N-(adamantan-1-ylcarbamothioyl)-2-chlorobenzamide (3g) possessing a 2-chlorophenyl substitution was the next most efficient compound belonging to the aryl series with IC50 value of 0.0087 ± 0.001 µM. The kinetic mechanism analyzed by Lineweaver–Burk plots revealed the non-competitive mode of inhibition for compound 3j. Moreover, in silico molecular docking against target protein (PDBID 4H9M) indicated that most of the synthesized compounds exhibit good binding affinity with protein. The compound 3j forms two hydrogen bonds with amino acid residue VAL391 having a binding distance of 1.858 Å and 2.240 Å. The interaction of 3j with amino acid residue located outside the catalytic site showed its non-competitive mode of inhibition. Based upon these results, it is anticipated that compound 3j may serve as a lead structure for the design of more potent urease inhibitors. 相似文献
973.
Hassan A. Albar Magda A. Abdallah Mosselhi A. N. Mosselhi Ahmad S. Shawali 《Heteroatom Chemistry》1996,7(4):225-228
Reaction of benzonitrilium N-phenylimide 3a with dibenzalacetone 1 yielded a mixture of the mono- and biscycloadducts 8a and 11a in a 1:1 ratio. A similar reaction of 1 with ethoxycarbonylnitrilium N-phenylimide 3b afforded a mixture of the cycloadducts 7b , 8b , and 12b in a 1:3:6 ratio, respectively. The structures of these products were established by spectral analyses and chemical transformations. The results invalidate the previously reported structure 4a assigned for the biscycloadduct isolated from the reaction of 3a with 1 . © 1996 John Wiley & Sons, Inc. 相似文献
974.
Ehab M. Abdalla Safaa S. Hassan Hussein H. Elganzory Samar A. Aly Heba Alshater 《Molecules (Basel, Switzerland)》2021,26(19)
New Pb(II), Mn(II), Hg(II), and Zn(II) complexes, derived from 4-(4-chlorophenyl)-1-(2-(phenylamino)acetyl)thiosemicarbazone, were synthesized. The compounds with general formulas, [Pb(H2L)2(OAc)2]ETOH.H2O, [Mn(H2L)(HL)]Cl, [Hg2(H2L)(OH)SO4], and [Zn(H2L)(HL)]Cl, were characterized by physicochemical and theoretical studies. X-ray diffraction studies showed a decrease in the crystalline size of compounds that were exposed to gamma irradiation (γ-irradiation). Thermal studies of the synthesized complexes showed thermal stability of the Mn(II) and Pb(II) complexes after γ-irradiation compared to those before γ–irradiation, while no changes in the Zn(II) and Hg(II) complexes were observed. The optimized geometric structures of the ligand and metal complexes are discussed regarding density functional theory calculations (DFT). The antimicrobial activities of the ligand and metal complexes against several bacterial and fungal stains were screened before and after irradiation. The Hg(II) complex has shown excellent antibacterial activity before and after γ-irradiation. In vitro cytotoxicity screening of the ligand and the Mn(II) and Zn(II) complexes before and after γ-irradiation disclosed that both the ligand and Mn(II) complex exhibited higher activity against human liver (Hep-G2) than Zn(II). Molecular docking was performed on the active site of MK-2 and showed good results. 相似文献
975.
976.
977.
A. Shailos M. El Hassan C. Prasad J. P. Bird D. K. FerryL. -H. Lin N. Aoki K. Nakao Y. OchiaiK. Ishibashi Y. AoyagiT. Sugano 《Superlattices and Microstructures》2000,27(5-6)
We present evidence for a re-entrant metal–insulator transition that arises in quantum dot arrays as the gate voltage is used to sweep their density of states past the Fermi level. The form of the temperature variation of the conductance observed in these arrays can be accounted for using a functional form derived from studies of the metal–insulator transition in two dimensions, although the values obtained for the fit parameters suggest that the behavior we observe here may be quite distinct to that found in two dimensions. 相似文献
978.
Lithium trifluoromethane-sulfonate (Li-TFMS:CF3SO3Li) irradiated by γ-rays showed an electron spin resonance (ESR) powder spectrum having the rhombicg-factor ofg xx = 2.0259 ± 0.0005,g yy = 2.0112 ± 0.0005 andg zz = 2.0025 ± 0.0005 and a triplet hyperfine coupling constant ofA xx/gβ= 0.8 ± 0.15 mT.A yy andA zz are not obtained because of the broadened spectrum. The energy levels,g-factor,A xx/gβ and optical absorption spectrum of several conceivable radicals such as C⋅F2SO3Li, CF3-S-O⋅ and CF3-S-O-O⋅ have been calculated by softwares MOPAC-V2 and Gaussian-98 based on ROHF (Restricted Hatree-Fock for open shell molecule). The most probable radical was ascribed to CF3-SO⋅ from both calculated and experimental results. The response to γ-ray dose and the thermal stability have been studied in addition to the effect of UV illumination for possible use of the signal intensity in ESR dosimetry. The obtained number of free radicals per 100 eV (G-value) was 1.23 ± 0.40. 相似文献
979.
A sensitive and selective electrochemical sensor for the determination of glutathione(GSH) was developed using a modified multiwall carbon nanotube paste electrode with 3,4 dihydroxy cinnamic acid as a mediator.This modified electrode showed very high electrocatalytic activity for the anodic oxidation of GSH.Under the optimized conditions,the electrocatalytic peak current showed a linear relationship with GSH concentration in the range of 0.5-400.0 μmol/L with a detection limit of 0.1 μmol/L GSH.The relative standard deviations for seven successive assays of 5.0 and 25.0 μmol/L GSH were 2.2% and 2.7%,respectively.The modified electrode was used for the determination of GSH compounds in real urine samples. 相似文献
980.
Sami Ullah Khan Hassan Waqas Taseer Muhammad Muhammad Imran Malik Zaka Ullah 《理论物理通讯》2020,72(10):105001-11
The current article investigates the impact of the bioconvection in an unsteady flow of magnetized Cross nanofluid with gyrotactic microorganisms and activation energy over a linearly stretched configuration. The analysis has been performed by utilizing the realistic Wu's slip boundary and zero mass flux conditions. The effects of nonlinear thermal radiation and the activation energy are also addressed. The governing flow equations are deduced to a dimensionless form by considering suitable transformations which are numerically targeted via a shooting algorithm. The physical visualization of each physical parameter governing the flow problem has been displayed graphically for distribution of velocity, temperature, concentration and motile microorganisms. The numerical treatment for the variation of skin friction coefficient, local Nusselt number, local Sherwood number and motile density number is performed in tabular forms. 相似文献