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排序方式: 共有202条查询结果,搜索用时 29 毫秒
1.
Simultaneous determination of triterpene saponins in ginseng drugs by high-performance liquid chromatography 总被引:3,自引:0,他引:3
A HPLC method for the simultaneous determination of 11 triterpene saponins with four-type aglycones (protopanaxadiol, protopanaxatriol, ocotillol and oleanolic acid types) in Ginseng drugs was developed and validated. Using a gradient of acetonitrile and 10 mM K-phosphate buffer (pH 5.80) as the mobile phase and UV detection at 196 nm, more than 18 ginsenosides with different aglycones were separated satisfactorily within 60 min. The detection limits (signal/noise> or =3) were 0.1 microg for ginsenosides Rb1, Rc, Rd, Re and Rg1, chikusetsusaponin III, and notoginsenoside R2, 0.2 microg for gisenoside Ro and chikusetsusaponin IVa, 0.3 microg for chikusetsusaponin IV, and 3 microg for majonoside R2. The calibration curve of each saponin had a correlation coefficient close to 1. Intra- and interday precisions were less than 2.1% (n=5) and 3.3% (n=15), respectively. The recovery rates of extraction were in the range of 96.4-102.7% for all ginsenosides. By adopting this method, the determinations of 11 ginsenosides in three Ginseng drugs derived from Panax ginseng, Panax vietnamensis var. fuscidiscus and Panax japonicus (Japan) were achieved. 相似文献
2.
Ahmed A. El-Asmy Taj Y. Al-Ansi Ragab R. Amin F. M. El-Shahat 《Transition Metal Chemistry》1990,15(1):12-15
Summary Several new complexes of the title ligand (H2MPTS) with CoII, NiII, CuII, and CdII have been prepared. Structural assignments of the complexes have been made based on elemental analysis, molar conductivity, magnetic moment and spectral (i.r.,1H n.m.r., reflectance) studies. The compounds are non-conductors in dimethylsulphoxide. The neutral molecule is coordinated to the metal(II) sulphate as a bidentate ligandvia the two carbonyl groups. The ligand reacts with the metal(II) chlorides with the liberation of two hydrogen ions, behaving as a bianionic quadridentate (NONO) donor. Enolization is confirmed by the pH-titration of H2 MPTS and its metal(II) complexes against NaOH. A distorted octahedral structure is proposed for the CuII complex, while a square planar structure is suggested for both CoII and NiII complexes. The stoichiometry of the complexes formed in EtOH and buffer solutions, their apparent formation constants and the ranges for obedience to Beer's law are reported for CoII, NiII and CuII ions. The ligand pK values are calculated. The antimicrobial activity of H2 MPTS and its CoII, NiII, CuII and MnII complexes is demonstrated. 相似文献
3.
Safaa El‐din H. Etaiw Hassan Marie Elsayed M. Shalaby Rabie S. Farag Fatma A. Elsharqawy 《应用有机金属化学》2019,33(9)
Orange prismatic crystals of the supramolecular coordination polymer (SCP) ∞3[Cu(CN)2(Me3Sn)(Pyz)], SCP 1 , were synthesized using a self‐assembly method under ambient conditions. Nanosized 1 was obtained using the same molar ratio in water by ultrasonic irradiation. SCP 1 was characterized using single‐crystal X‐ray diffraction, elemental analysis, thermal analysis and Fourier transform infrared spectroscopy. SCP 1 and its nanosized 1 particles were also examined using powder X‐ay diffraction and scanning electron microscopy. The luminescence emission of SCP 1 was studied as well as its use as a sensor for the detection of common organic solvents and metal ions. Also, the catalytic activities of nanosized 1 towards various organic dyes were investigated under ambient conditions, UV irradiation and ultrasonic irradiation. Nanosized 1 as a heterogeneous nanoparticle catalyst exhibits high catalytic activity for the degradation of eosin‐Y and acid blue dyes. The mechanism of degradation investigated using various scavenger techniques is proposed and discussed. The catalytic oxidation process is mainly caused by ?OH radicals. 相似文献
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An ultrasound-assisted nanoscaled supramolecular coordination polymer (nanosized 1′ ) has been synthesized using a self-assembly reaction of K3[Cu (CN)4] and hexamethylenetetramine in the presence of Me3SnCl under ambient conditions. Nanosized 1′ was examined using elemental analysis, Fourier transform–infrared, transmission electron microscopy, scanning electron microscopy and X-ray powder diffractions. It was structurally compared with the single crystal supramolecular coordination polymer ∞3[Cu6(CN)7(C6H12N4)2(OH3)]; SCP 1. The photocatalytic activities of nanosized 1′ and SCP 1 toward different hazardous organic dyes were determined under ambient, UV-light irradiation and ultrasonic conditions. SCP 1 and nanosized 1′ as heterogeneous nanoparticles catalysts exhibited high catalytic activity for degradation of Congo Red, Methyl Violet 2B and Methylene Blue dyes. The effects of operational parameters on catalytic degradation process, identification of the degradation products and recycling of the catalyst were also investigated. SCP 1 and nanosized 1′ are recyclable heterogeneous catalysts and can be reused with efficient activities. The mechanism of degradation using different scavenger techniques iss proposed and discussed. The catalytic oxidation process is mainly caused by •OH radicals. 相似文献
6.
Mohamed A. Korany Hadir M. Maher Shereen M. Galal Marwa A. A. Ragab 《Analytical and bioanalytical chemistry》2013,405(14):4835-4848
7.
Eman M. Othman Amany A. Bekhit Mohamed A. Anany Thomas Dandekar Hanan M. Ragab Ahmed Wahid 《Molecules (Basel, Switzerland)》2021,26(10)
The present study reports the synthesis of new purine bioisosteres comprising a pyrazolo[3,4-d]pyrimidine scaffold linked to mono-, di-, and trimethoxy benzylidene moieties through hydrazine linkages. First, in silico docking experiments of the synthesized compounds against Bax, Bcl-2, Caspase-3, Ki67, p21, and p53 were performed in a trial to rationalize the observed cytotoxic activity for the tested compounds. The anticancer activity of these compounds was evaluated in vitro against Caco-2, A549, HT1080, and Hela cell lines. Results revealed that two (5 and 7) of the three synthesized compounds (5, 6, and 7) showed high cytotoxic activity against all tested cell lines with IC50 values in the micro molar concentration. Our in vitro results show that there is no significant apoptotic effect for the treatment with the experimental compounds on the viability of cells against A549 cells. Ki67 expression was found to decrease significantly following the treatment of cells with the most promising candidate: drug 7. The overall results indicate that these pyrazolopyrimidine derivatives possess anticancer activity at varying doses. The suggested mechanism of action involves the inhibition of the proliferation of cancer cells. 相似文献
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10.
F
A1:Ag+ color center at the low coordination (100) and (110) surface sites of KCl and KBr thin films play an important role in providing
tunable laser oscillation and adsorbatesubstrate interactions. Double-well potentials at this site are investigated using
ab initio molecular electronic structure calculations. The calculated Stokes shifted (optical transition bands), opticaloptical
conversion efficiencies, the probability of orientational destruction, exciton (energy) transfer and Glasner-Tompkins empirical
rule suggest that laser light generation is sensitive to (i) the lattice anion, (ii) the coordination number of surface ions,
and (iii) the choice of the basis set centered on the anion vacancy. The adsorbate-substrate interactions were found to be
dependent on the electronegativity of the adatom and on the lattice anion. Optimised geometries and the coadsorption of CO
and (F, Cl, Br, I) on KCl and KBr (100) crystals are presented. Calculated chemisorption energies for CO on the (halogen atom/defect
free sites of KCl and KBr (100) crystals) showed that the coadsorption of halogen atom tends to block other adsorbate-substrate
interactions at the nearest neighbour sites. Thus if halogen atom coverage increases, the CO prefers to be adsorbed on the
K+ site of the KCl and KBr (100) surfaces and on KBr relative to KCl.
相似文献