Rutin and Quercetin Decrease Cholesterol in HepG2 Cells but Not Plasma Cholesterol in Hamsters by Oral Administration

Rutin (R) and quercetin (Q) are two widespread dietary flavonoids. Previous studies regarding the plasma cholesterol-lowering activity of R and Q generated inconsistent results. The present study was therefore carried out to investigate the effects of R and Q on cholesterol metabolism in both HepG2 cells and hypercholesterolemia hamsters. Results from HepG2 cell experiments demonstrate that both R and Q decreased cholesterol at doses of 5 and 10 µM. R and Q up-regulated both the mRNA and protein expression of sterol regulatory element binding protein 2 (SREBP2), low-density lipoprotein receptor (LDLR), and liver X receptor alpha (LXRα). The immunofluorescence study revealed that R and Q increased the LDLR expression, while only Q improved LDL-C uptake in HepG2 cells. Results from hypercholesterolemia hamsters fed diets containing R (5.5 g/kg diet) and Q (2.5 g/kg diet) for 8 weeks demonstrate that both R and Q had no effect on plasma total cholesterol. In the liver, only Q reduced cholesterol significantly. The discrepancy between the in vitro and in vivo studies was probably due to a poor bioavailability of flavonoids in the intestine. It was therefore concluded that R and Q were effective in reducing cholesterol in HepG2 cells in vitro, whereas in vivo, the oral administration of the two flavonoids had little effect on plasma cholesterol in hamsters.     

Chemical composition and antioxidant activity of Borago officinalis L. leaf extract growing in Algeria

The aqueous and hydroalcoholic extracts of borage (Borago officinalis) leaves from Annaba region (Algeria) were preliminary analyzed for their phenolic profile (total phenolics, total flavonoids, total flavonols, total tannins and total anthocyanins). These extracts were evaluated for their antioxidant properties by different methods such as DPPH radical scavenging, test NBT and total antioxidant activity. The two extracts have exhibited a high antiradical capacity. Indeed, the ethanolic extract showed the lower IC50 values and the highest amount of phenolics (94.09 ± 1.72 mg gallic acid/g dry extract). Using LC-MS/MS analysis, it was possible to identify phenolic acids, flavonoids, sterol and for the first time oleuropein was identified in the aqueous extract of the plant. The obtained results have demonstrated that phenolic compounds are the major contributor to the antioxidant activity of plants.     

Preparation of CuO-Nanoparticle-Modified Electrode and Its Application in the Determination of Rutin

Abstract

In this article, highly pure, well-dispersed, 10-nm CuO nanoparticles were obtained by a hydrothermal reduction process, with oxalic acid as precipitator. The CuO nanoparticles were characterized by x-ray powder diffraction, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy. The CuO nanoparticles were modified onto a gold electrode to study the effect on the redox of the rutin. Cyclic voltammetry results show that the CuO nanoparticles were very active for rutin and that the CuO-nanoparticle-modified electrode can even determine rutin in a certain range of concentration from 5.0 × 10^?7 to 5.0 × 10^?4 mol L^?1 by differential pulse voltammertry, which provides a new application for CuO nanoparticles.     

A survey of metabolic changes in potato leaves by NMR‐based metabolic profiling in relation to resistance to late blight disease under field conditions

Non‐targeted nuclear magnetic resonance (NMR)‐based metabolic profiling was applied to potato leaves to survey metabolic changes associated with late blight resistance under field conditions. Potato plants were grown in an experimental field, and the compound leaves with no visible symptoms were collected from 20 cultivars/lines at two sampling time points: (i) the time of initial presentation of symptoms in susceptible cultivars and (ii) 12 days before this initiation. ¹H NMR spectra of the foliar metabolites soluble in deuterium oxide‐ or methanol‐d₄‐based buffers were measured and used for multivariate analysis. Principal component analysis for six cultivars at symptom initiation showed a class separation corresponding to their levels of late blight resistance. This separation was primarily explained by higher levels of malic acid, methanol, and rutin and a lower level of sucrose in the resistant cultivars than in the susceptible ones. Partial least squares regression revealed that the levels of these metabolites were strongly associated with the disease severity measured in this study under field conditions. These associations were observed only for the leaves harvested at the symptom initiation stage, but not for those collected 12 days beforehand. Subsequently, a simple, alternative enzymatic assay for l ‐malic acid was used to estimate late blight resistance, as a model for applying the potential metabolic marker obtained. This study demonstrated the potential of metabolomics for field‐grown plants in combination with targeted methods for quantifying marker levels, moving towards marker‐assisted screening of new cultivars with durable late blight resistance. Copyright © 2016 John Wiley & Sons, Ltd.     

Analysis of Commercial Multi-vitamin Preparation by HPLC with Diode Array Detector

Abstract

A simple and efficient HPLC analysis method has been developed to simultaneously analyse complicated multi-vitamin preparations, including vitamin B complexes, vitamin C, orotic acid, methionine, calcium pantothenate, nicotinamide, biotin, folic acid and rutin, without using expensive ion pairing reagent. Diode array detector and adjustment of the mobile phase to pH 5.6 are required in the study. This method has been validated with good linearity, reproducibility, recovery and accuracy for analysis of commercial multi-vitamin products.     

Determination of Active Ingredients of Apocynum Venetum by Capillary Electrophoresis with Electrochemical Detection

 A simple, reliable and reproducible method, based on capillary electrophoresis (CE) with electrochemical detection (ED), for the determination of three active ingredients of both Apocynum Venetum compound tablets and medicinal herbs was described. The active ingredients mainly consist of rutin, d-catechin and quercetin. Operated in a wall-jet configuration, a 300 μm diameter carbon-disk electrode was used as the working electrode, which exhibits good responses at + 950 mV (vs. SCE) for the three analytes. Under the optimum conditions, the analytes were base-line separated within 19 min, and excellent linearity was obtained in the concentration range from 1.0 × 10⁻⁴ g/ml to 1.0 × 10⁻⁶ g/ml. The detection limit (S/N = 3) was 3.0 × 10⁻⁷ g/ml, 5.0 × 10⁻⁷ g/ml, and 4.0 × 10⁻⁷ g/ml for d-catechin, rutin and quercetin, respectively. This work provides a useful method for the analysis of traditional Chinese medicines. Received July 12, 2000. Revision January 3, 2001.     

毛细管电泳法测定桑叶中的黄酮类成分──芦丁和槲皮素

 采用高效毛细管电泳法分离测定了新疆不同地区、不同采集期、不同品种的桑叶中的黄酮类成分芦丁、槲皮素的含量。以含有体积分数为 15 %甲醇的 10mmol/L的磷酸二氢钠 2 0mmol/L的硼砂溶液 (pH 8 6 2 )为电泳缓冲液 ,采用压力进样方式 ,在 2 5℃ ,2 0kV恒压下进行电泳分离 ,并在 2 45nm波长处检测。结果表明 ,桑叶中的两种目标组分在 12min内完全分离 ,且有良好的线性关系 ;芦丁和槲皮素的加样回收率分别为 95 6 4%和99 36 % ,其RSD分别为 2 2 5 %和 1 79% (n =6 )。方法简单、准确、快速。     

Investigation of the Interaction Between Rutin and Trypsin in Solution by Multi-Spectroscopic Method

ABSTRACT

The interactions between rutin and trypsin were investigated by UV-Vis absorption, CD, fluorescence, resonance light-scattering spectra, synchronous fluorescence, and three-dimensional fluorescence spectra techniques under physiological pH 7.40. Rutin effectively quenched the intrinsic fluorescence of trypsin via static quenching. The enthalpy change and entropy change were estimated to be ?8.23 kJ·mol^?1 and 53.66 J·mol^?1·K^?1 according to the van't Hoff equation. The process of binding rutin to trypsin was a spontaneous molecular interaction procedure. This result indicates that hydrophobic and electrostatic interactions played a major role in stabilizing the complex. The conformation of trypsin was discussed by CD, synchronous, and three-dimensional fluorescence techniques.     

运用二维相关红外光谱分析技术研究芦丁的热微扰过程

采用傅里叶变换红外光谱法(FTIR)和二维相关分析(2D correlation analysis)技术研究了固态芦丁20℃～160℃的升温过程。实验结果显示，芦丁红外光谱的特征峰在红外图上随着温度升高变化不明显，说明实验中芦丁分子没有发生氧化反应。借助于二维相关分析，提高了谱图的分辨率，将芦丁分子中不同苯环的骨架振动峰在二维同步图上显示并区分开来。同时还揭示了芦丁分子内各官能团之间的相互作用，反映了在热微扰过程中这些基因之间的协同关系和变化的先后顺序。分析结果表明；芦丁分子中两个苯环，杂环的C=O及=C-O-C基因发生了相互作用。其变化的顺序是和含氧杂环相连的苯环，C=O，=C-O-C和含氧杂环相并的苯环。此结论与芦丁的氧化反应机理相一致。总之，二维相关红外分析可以作为研究芦丁热微扰过程中结构动态变化的一种新方法，也为芦丁在氧化过程中的机理研究提供了一个重要的理论依据。     

Kinetic Determination of Microquantities of Rutin by Perturbation of the Bray-Liebhafsky Oscillatory Reaction in an Open System

A kinetic method is described for the microquantitative (microconcentration/microvolume) determination of rutin based on potentiometric monitoring of the concentration perturbations of the Bray-Liebhafsky (BL) oscillatory reaction being in a non-equilibrium stationary state close to a bifurcation point. The experiments are carried out in an open reactor. The response of the matrix system to perturbations by different concentrations of rutin ethanolic solutions is followed by a Pt-electrode. In the concentration range between 7.8×10^–8moldm^–3 and 9.1×10^–6mol dm^–3, we found a linear dependence of the maximal potential shift, E_m, on the logarithm of the rutin concentrations. The unknown concentrations can be determined from the calibration curve up to an accuracy of ±5%. The detection limit is 3.6×10^–8mol dm^–3. The amount of required sample can be as small as 10µL.