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81.
《Biomedical chromatography : BMC》2017,31(3)
A simple, accurate, and reproducible high‐performance liquid chromatography (HPLC) method has been developed and validated for the quantification of quercetin (QR) in rat plasma. The method involves a simple protein precipitation procedure to extract both QR and thymoquinone (TQ), the internal standard. The chromatographic analysis was achieved on a Shimadzu LC 20 A HPLC system equipped with a Supelcosil LC‐18 T C18 column and an isocratic mobile phase consisting of 0.3% trichloroacetic acid in water and acetonitrile HPLC‐grade (50:50, v /v) run at a flow rate of 0.9 mL/min for 13 min. The UV detection wavelength was set at 254 nm. The method exhibited good linearity (R 2 > 0.994) over the assayed concentration range (0.10–25 μg/mL) and demonstrated good intra‐day and inter‐day precision and accuracy (relative standard deviations and the deviation from predicted values were <20%). This method was also successfully applied for studying the pharmacokinetics of QR in rats following a single oral dose of QR to evaluate its pharmacokinetic parameters in rats. 相似文献
82.
《Journal of separation science》2018,41(17):3459-3466
In this study, a highly sensitive and selective sample pretreatment procedure using molecularly imprinted silica nanoparticles was developed for the extraction and determination of quercetin in red wine samples coupled with high‐performance liquid chromatography with ultraviolet detection. The imprinted silica nanoparticles were prepared in the presence of N‐acryoyl‐l ‐aspartic acid (functional monomer), quercetin (template), azobisisobutyronitrile (initiator) and methylene bisacrylamide (cross‐linker) and methanol/water (porogen) via surface‐initiated reversible addition‐fragmentation chain transfer polymerization. Surface characterization was performed and several imprinting parameters were investigated, and the results indicated that adsorption of quercetin on the imprinted silica nanoparticles followed a pseudo‐first‐order adsorption isotherm with a maximum adsorption capacity at 26.4 mg/g within 60 min. The imprinted silica nanoparticles also showed satisfactory selectivity towards quercetin as compared with its structural analogues. Moreover, the imprinted nanoparticles preserved their recognition ability even after five adsorption–desorption cycles. Meanwhile, the nanoparticles were successfully applied to selective extraction of quercetin from red wine with a high recovery (99.7–100.4%). The limit of detection was calculated to be 0.058 μg/mL with a correlation coefficient 0.9996 in the range of 0.2–50 μg/mL. As a result, the developed selective extraction method using molecular imprinting technology simplifies the sample pretreatment procedure before determination of quercetin in real samples. 相似文献
83.
Summary Capillary electrophoresis with amperometric detection has been evaluated for the simultaneous determination of rutin and quercetin.
The cyclic voltammogram, hydrodynamic voltammogram, and the effects of pH, concentration of buffer and sodium dodecyl sulfate
(SDS), and amount of organic modifier on the separation and the detection were studied. The optimized conditions were: detection
potential 1.2V, separation at 12 kV, 5 s at 15 kV for sample injection, running electrolyte 20 mmol L−1 borate buffer, pH 8.8, containing 40 mmol L−1 SDS and 10% acetonitrile. The detection limit of the method was low, 0.001 and 0.0005 mg mL−1, for rutin and quercetin, respectively; the linear ranges were wide −0.005–0.5 and 0.005–0.4 mg mL−1, respectively. The variations in peak current and migration time for eight consecutive injections of a standard solution
containing 0.1 mg mL−1 of each compound were 4.78 and 3.63%, and 6.50 and 2.59% for rutin and quercetin, respectively. The levels of the two compounds
in traditional Chinese herbal drugs were easily determined. 相似文献
84.
M. D. Alaniya N. Sh. Kavtaradze C. Bassarello A. V. Skhirtladze C. Pizza I. Kutateladze 《Chemistry of Natural Compounds》2006,42(6):681-685
New flavonoid oligosides, the structures of which were established by chemical transformations and UV, IR, PMR, and 13C NMR spectra, were isolated from Astragalus galegiformis leaves.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 555–558, November–December, 2006. 相似文献
85.
M. P. Yuldashev B. A. Muminova A. A. Drenin E. Kh. Botirov 《Chemistry of Natural Compounds》2007,43(1):34-36
The new flavone glucoside viscioside, luteolin-4′-O-β-D-galactopyranoside, in addition to the known flavonoids apigenin, luteolin, quercetin, cinaroside, luteolin-4′-O-β-D-glucoside, and isoquercitrin were isolated from the aerial part of Vicia subvillosa.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 30–31, January–February, 2007. 相似文献
86.
氧的浓度超过正常值会引起毒性效应。超氧负离子基(O_2~(?))作为生物体内代谢产生的一种活性中间体,在发现超氧化物歧化酶(SOD)是其专一清除剂后,引起人们广泛的兴趣,并对 O_2~(?)与人类的某些疾病和癌症的关系进行了研究。由于·OH、~1O_2和 HO_2等也是高活性的物质,有人认为在研究 O_2~(?)的毒害效应时,不应忽视这些由 O_2~(?)可衍生出来的活性氧。为阐明 O_2~(?)在生物体内的作用,还需对 O_2~(?)化学作更多更深入的基础工作。黄酮类化合物是一大类重要的有生化意义的化合物,已有许多关于槲皮素氧化反应的报 相似文献
87.
Rong LEI Hu Wei LIU Na LI Ke''''An LI College of Chemistry Molecular Engineering Peking University Beijing 《中国化学快报》2006,(11)
Ru(bpy)32 electrochemiluminescence (ECL) was applied to determine quercetin. It was found that ECL intensity of Ru(bpy)32 could be enhanced in the presence of quercetin in basic solution, and the enhanced light emission intensity was proportional to the concentration of quercetin over the range of 1×10-6 mol/L to 2×10-4 mol/L. 相似文献
88.
89.
90.
Zareath Pamela Terán Baptista Analía de los Angeles Gómez Raphaël Grougnet Tsvetelina Mandova Pedro Adrían Aredes Fernandez 《Natural product research》2020,34(12):1782-1785
AbstractExtracts from aerial parts of medicinal plants from northwest Argentina were screened for antibacterial activity against the phytopathogenic strains namely CECT 124 (Pseudomonas corrugata), CECT 126 (P. syringae pv. tomato), CECT 225 (Erwinia carotovora var. carotovora), CECT 472 (Agrobacterium tumefaciens) and CECT 792 (Xanthomonas campestres pv. vesicatoria). Leaves and stems of Aspidosperma quebracho-blanco, Schinus fasciculatus, S. gracilipes, Amphilophium cynanchoides and Tecoma stans were separately extracted with solvents of increasing polarity to obtain the dichloromethane (fCH2Cl2), ethyl acetate (fEtAc) and methanol extracts (fMeOH), respectively. Among the thirty extracts tested, only fEtAc from leaves and stems of S. fasciculatus reached the IC50 against the five bacterial strains tested (IC50?=?0.9?mg/ml). The fEtAc from the leaves contained kaempferol, quercetin and agathisflavone which had moderate to strong antibacterial activity. This extract and its identified flavonoids showed synergic (CECT 124,126 and 792) or additive effects (CECT 472 and 225) in mixtures with Kocide 3000. 相似文献