共查询到20条相似文献,搜索用时 125 毫秒
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槲皮素-锆(Ⅳ)-柠檬酸-十二烷基磺酸钠体系荧光光度法测定槲皮素的研究 总被引:2,自引:0,他引:2
在 0 .5 4 mol/L盐酸介质中 ,有十二烷基磺酸钠的存在下 ,槲皮素与锆 ( )和柠檬酸形成多元荧光配合物 ,其组成比为槲皮素∶锆 ( )∶柠檬酸 =1∶ 2∶ 2。配合物的激发与发射波长分别为432和 495 nm时 ,槲皮素浓度在 1 .0× 1 0 -6~ 1 .0× 1 0 -5mol/L范围内与荧光强度成线性关系 ,检出限为 2 .34× 1 0 -7mol/L。该法用于鸡骨草中黄酮类化合物的测定 ,结果满意 相似文献
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In this study, a metal‐complexing imprinted polymer has been prepared using the complex of Quercetin and Co(II) (Qu‐Co(II)) as template (Quercetin is a kind of flavonoid, which is a class of important active ingredients of Chinese herbs.). The polymers were synthesized in the mixed solution of methanol and tetrahydrofuran by photo‐ and thermal‐initiated polymerization, respectively. The complex ratio between Qu and Co(II), as well as the ternary complexation of Qu, Co(II), and acrylamide, was assessed in differential UV absorption spectrometry. Fourier transform infrared spectra (FTIR) were useful to verify whether the polymers prepared in two ways had the same molecular structure. The effect of initiation mode was studied by the transmission electron microscopy (TEM) and equilibrium binding experiments. Isothermal adsorption and selectivity experiments showed that molecularly imprinted polymers exhibited high affinity and specific recognition for Qu by introducing cobalt ion. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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Abstract Flavonoids, such as Quercetin, are the main polyphenol compounds found in extractives. When complexing with transition metal ions, these extractives may induce a significant discoloration to mechanical pulps. In this study, the effect of metallic extractive complexes was investigated using a model compound, Quercetin. It was confirmed that the complexes formed between some metal ions and Quercetin are strongly colored. However, most of the strong absorbance in visible light due to metallic Quercetin complexes, can be eliminated by the addition of diethylenetriaminepentaacetic acid (DTPA). The metal ions studied were Fe(III), Cu(II), Mn(II) and AI(III). 相似文献
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Andrea Roedig-Penman Michael H. Gordon 《Journal of the American Oil Chemists' Society》1998,75(2):169-180
The effect of quercetin and myricetin on the stability of sunflower oil and oil-in-water emulsions was studied by storage
experiments monitored by measurement of peroxide values, conjugated dienes, and headspace volatile analysis. Myricetin showed
strong antioxidant activity in oils stored at 60 or 30°C and in oil-in-water emulsions stored at 30°C, whether tocopherols
or citric acid were present or not; however, quercetin showed similar antioxidant activity in stripped sunflower oil but no
activity in oils that contained tocopherols and citric acid. This showed that myricetin is effective owing to strong radical
scavenging and metal-chelating properties, whereas quercetin has weaker radical scavenging activity, although it is also active
by metal-chelation. The effects of copper and iron salts on the antioxidant activity of myricetin and quercetin were studied
in sunflower oil and oil-in-water emulsions. Quercetin and myricetin enhanced the prooxidant effect of cupric chloride in
oil-in-water emulsions (pH 7.4), but this effect was not observed with cupric stearate. The addition of myricetin to emulsions
that contained ferric chloride at pH 5.4 also produced a strong prooxidant effect, and small prooxidant effects of flavonols
were also detected in the presence of cupric chloride under these conditions. However, myricetin and quercetin reduced the
prooxidant effect of ferric palmitate in oils. Myricetin also showed a strong antioxidant effect in oil that contained cupric
stearate, although quercetin had no significant effect on the oxidative stability of this system. It therefore appears that
flavonols may exert a prooxidant effect in the presence of metal salts, but the nature of the metal salt is important in determining
whether a prooxidant effect occurs. 相似文献
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建立快速检测杜仲中两种黄酮苷元槲皮素与山奈酚的高效液相色谱方法,并测定水解前后杜仲叶与杜仲素黄酮苷元的含量。采用HPLC法同时测定黄酮苷元,色谱柱为Diamonsil C18(4.6 mm×250 mm,5μm),以甲醇-0.2%磷酸(63∶37)为流动相,检测波长为370 nm,流速1.0 mL/min,柱温为30℃。槲皮素和山奈酚分别在0.5~80μg/mL和0.5~18μg/mL内线性关系良好,该检测方法能迅速、准确检测水解前后杜仲叶和杜仲素中槲皮素和山奈酚的含量;水解工艺可明显提高杜仲黄酮苷元含量。 相似文献
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Physicochemical characterization and antioxidant activity of quercetin‐loaded chitosan nanoparticles
Quercetin is an abundant flavonoid in food plants with numerous biological activities and widely used as a potent antioxidant. Being sparingly soluble in water and subject to degradation in aqueous intestinal fluids, the absorption of quercetin is limited upon oral administration. In the present study, chitosan nanoparticles and quercetin‐loaded nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. The encapsulation of quercetin in the chitosan nanoparticles were confirmed by differential scanning calorimetry, X‐ray powder diffractometry, Fourier transformed infrared spectroscopy, ultraviolet‐visible spectrum, and fluorescence spectrum. The morphology of the nanoparticles was characterized by atomic force microscopy. The antioxidant activity of the quercetin‐nanoparticles was also evaluated in vitro by two different methods (free radical scavenging activity test and reducing power test), which indicates that inclusion of quercetin in chitosan nanopaticles may be useful in improving the bioavailabilty of quercetin. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
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Dr. Minna Rahnasto‐Rilla Dr. Tarja Kokkola Dr. Elina Jarho Dr. Maija Lahtela‐Kakkonen Dr. Ruin Moaddel 《Chembiochem : a European journal of chemical biology》2016,17(1):77-81
Sirtuin 6 (SIRT6) is an NAD+‐dependent histone deacetylase enzyme that is involved in multiple molecular pathways related to aging. Initially, it was reported that SIRT6 selectively deacetylated H3K9Ac and H3K56Ac; however, it has more recently been shown to preferentially hydrolyze long‐chain fatty acyl groups over acetyl groups in vitro. Subsequently, fatty acids were demonstrated to increase the catalytic activity of SIRT6. In this study, we investigated whether a series of N‐acylethanolamines (NAEs), quercetin, and luteolin could regulate SIRT6 activity. NAEs increased SIRT6 activity, with oleoylethanolamide having the strongest activity (EC50 value of 3.1 μm ). Quercetin and luteolin were demonstrated to have dual functionality with respect to SIRT6 activity; namely, they inhibited SIRT6 activity with IC50 values of 24 and 2 μm , respectively, and stimulated SIRT6 activity more than sixfold (EC50 values of 990 and 270 μm , respectively). 相似文献
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Barbora Boansk Monika Bartekov Kristína Ferenczyov Mria Fogarassyov Lucia Kindernay Miroslav Baran
ík 《International journal of molecular sciences》2021,22(9)
Several mechanisms may contribute to cardiovascular pathology associated with diabetes, including dysregulation of matrix metalloproteinases (MMPs). Quercetin (QCT) is a substance with preventive effects in treatment of cardiovascular diseases and diabetes. The aim of the present study was to explore effects of chronic QCT administration on changes in heart function in aged lean and obese Zucker Diabetic Fatty (ZDF) rats and that in association with MMPs. Signaling underlying effects of diabetes and QCT were also investigated. In the study, we used one-year-old lean and obese ZDF rats treated for 6 weeks with QCT. Results showed that obesity worsened heart function and this was associated with MMP-2 upregulation, MMP-28 downregulation, and inhibition of superoxide dismutases (SODs). Treatment with QCT did not modulate diabetes-induced changes in heart function and MMPs. However, QCT activated Akt kinase and reversed effects of diabetes on SODs inhibition. In conclusion, worsened heart function due to obesity involved changes in MMP-2 and MMP-28 and attenuation of antioxidant defense by SOD. QCT did not have positive effects on improvement of heart function or modulation of MMPs. Nevertheless, its application mediated activation of adaptive responses against oxidative stress through Akt kinase and prevention of diabetes-induced negative effects on antioxidant defense by SODs. 相似文献