Domestication of Plants of Ugni molinae Turcz (Myrtaceae) Interferes in the Biology of Chilesia rudis (Lepidoptera: Erebidae) Larvae

In terms of the domestication process in murtilla, studies have found changes in the concentration of phenolic compounds, with reduction of chemical defense of plants, depending on the change in the feeding behavior of insects. Thus, we hypothesized that the domestication of Ugni molinae decreases the content of phenolic compounds and modifies the feeding preference of Chilesia rudis larvae. Leaves of three parental ecotypes and four cultivated ecotypes were used in preference experiments to evaluate the mass gain and leaves consumption of larvae. Phenolic extracts from leaves of U. molinae were analyzed by HPLC. Identified compounds were incorporated in an artificial diet to assess their effect on mass gain, consumption, and survival of the larvae. The presence of phenolic compounds in bodies and feces was also evaluated. In terms of choice assays, larvae preferred parental ecotypes. Regarding compounds, vanillin was the most varied between the ecotypes in leaves. However, plant domestication did not show a reduction in phenolic compound concentration of the ecotypes studied. Furthermore, there was no clear relation between phenolic compounds and the performance of C. rudis larvae. Whether this was because of sequestration of some compounds by larvae is unknown. Finally, results of this study could also suggest that studied phenolic compounds have no role in the C. rudis larvae resistance in this stage of murtilla domestication process.     

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.     

Destabilizing the interplay between miR-1275 and IGF2BPs by Tamarix articulata and quercetin in hepatocellular carcinoma

Insulin-like growth factor-2 binding proteins (IGF2BPs) are oncogenic RNA-binding proteins, highly up-regulated in HCC, and were recently validated as direct targets of the tumour suppressor miR-1275. It is worth noting that around 47% of FDA approved anticancer drugs are derived from plants. Modulation by miRNAs and their cellular signalling cascades could constitute new pathways by which these phytochemicals exert their effects. This study aimed to investigate the potential use of Tamarix articulata, quercetin and epigallocatechin gallate (EGCG) in HCC and how these phytochemicals could epigenetically modulate the IGF axis using their impact on miR-1275. T. articulata ethyl acetate fraction significantly reduced the viability of Huh-7 cells compared to control cells. Treatment with T. articulata ethyl acetate fraction, quercetin and EGCG significantly enhanced miR-1275, while suppressed IGF2BP1 and IGF2BP3 mRNA expression levels. In summary, T. articulata, quercetin and EGCG have important implications for HCC molecular-targeted therapy through destabilizing the interplay between miR-1275 and the IGF axis.     

Enhanced in vitro anticancer activity of quercetin mediated by functionalized CdTe QDs

We report in this study the effects of red-emitting CdTe QDs capped with cysteamine(Cys-CdTe) on the in vitro anticancer activity of the well-known flavenoid quercetin(Qu). Various techniques, including the methylthiazolyldiphenyl-tetrazolium bromide assay, the real-time cell electronic sensing system, the optical and fluorescence imaging, and electrochemical methods have been utilized to study the potential interactions of Cys-CdTe QDs with Qu. The observations demonstrate that the safe-dosage Cys-CdTe QDs can greatly improve the drug uptake and enhance the inhibition efficiency of Qu towards the proliferation of cancer cells such as HepG2 cells. This study implies that Cys-CdTe QDs may be used for cancer therapy and that they exert a synergic anticancer effect when bound to drug molecules.     

任务教学法在药物分析综合设计性实验中的应用*

为提高学生探索精神,锻炼学生科学创新思维,培养出更符合社会需要的药学专业型人才,将综合设计性实验的内容引入药物分析实验课程中。以高效液相色谱法测定乌蔹莓中槲皮素、木犀草素的含量,并进行方法学考察为设计任务,通过指导学生查阅资料、设计实验方案、实施实验方案、分析讨论结果,加深学生对基础理论知识的理解;提高学生查阅文献能力、知识扩展能力、自学能力、创新能力等,为就业及深造奠定基础。     

Effects of a Constant Magnetic Field on the Electrochemical Reactions of Quercetin

The paper presents a study of the effect of a constant magnetic field (CMF) on the basic processes of quercetin electrochemical reactions. According to the observation made in previous studies, the presence of a double bond in the C-ring of quercetin enhances the antioxidant properties of that compound, whereas the presence of −OH groups also affects the antioxidant properties. Using cyclic voltammetry it was found that the constant magnetic field improves the efficiency of quercetin electrooxidation, especially of the third stage of the process, i. e. the stage in which the oxidation of the OH groups in the A-ring is the most difficult. The use of HPLC confirmed the electrochemical measurements and the results of cyclic voltammetry studies. The beneficial effect of the magnetic field on the efficiency of quercetin oxidation was confirmed by the results of impedance spectroscopy measurements.     

肝肿瘤细胞HepG2代谢指纹及代谢足迹的NMR分析

细胞代谢特征的分析是认识细胞生物化学过程物质基础的一个关键点. 该文使用培养72 h的肝肿瘤细胞HepG2为模型，使用一维与二维核磁共振谱学分析方法， 分析了该细胞本身及其培养液中代谢物的组成，确定了50余种覆盖三羧酸循环、糖酵解、氨基酸合成、脂肪酸与胞膜代谢、嘌呤与嘧啶代谢等多个代谢途径的代谢物，发现细胞本身与培养基中代谢物组成能够分别提供“细胞代谢指纹”与“细胞代谢足迹”等互补性信息. 同时发现此方法可用于研究植物次生代谢物槲皮素对肝肿瘤细胞HepG2代谢的影响. 结果表明，核磁共振波谱技术是分析细胞代谢组特征和研究药物对细胞代谢影响规律的有效手段.     

槲皮素-3-O-丙基衍生物的合成及生物活性研究

槲皮素是具有丰富生物活性的黄酮类化合物,药理活性显著。本文以槲皮素为先导物,选择性对C环3位羟基进行修饰,以廉价的芦丁为原料,经苄基保护、Williamson成醚反应,再经Pd/C催化加氢脱苄基得到28个未见文献报道的槲皮素-3-O-丙基衍生物,其结构经¹H NMR、¹³C NMR、ESI-MS进行确证。采用MTT法考察了所合成化合物对人食管鳞癌（EC109）、人胃癌（HGC27）、人乳腺癌（MCF-7）、小鼠黑色素瘤（B16-F10）的增殖抑制作用。结果显示,通过化学方法对槲皮素结构进行修饰后,其体外抗肿瘤活性增强。其中,化合物F3(IC₅₀=5.23±0.37μmol/L)、F5(IC₅₀=2.63±0.09μmol/L)对小鼠黑色素瘤（B16-F10）抑制作用比5-氟尿嘧啶(IC₅₀=14.38±0.27μmol/L)好,值得进一步研究。     

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.