基于HPLC测定的响应面法优化航天紫花苜蓿中黄酮的提取工艺

本试验以航天紫花苜蓿为研究对象,通过乙醇浓度、液料比、回流时间、超声时间4个影响因素进行响应面试验设计,建立了航天紫花苜蓿中黄酮的提取工艺模式;用高效液相色谱法测定最佳工艺下提取的航天紫花苜蓿中黄酮的含量。结果表明,其最佳提取工艺条件为：乙醇浓度50.5%、液料比15.2mL/g、回流时间2.3h、超声时间21.0min,此工艺下黄酮的含量为10.338%。HPLC检测重现性良好,表明该试验方法设计合理,为航天紫花苜蓿的深层次研究提供了一定参考。     

类黄酮物质及查尔酮合酶在油菜性状改良中的作用

类黄酮化合物(Flavonoids)是一类重要的植物次生代谢产物,查尔酮合酶(CHS)是类黄酮物质形成步骤中的一个关键酶,影响植物的多种重要性状.油菜是重要的经济作物,许多植物的CHS基因已经被克隆并进行了基因工程的研究,但CHS与油菜性状发育的关系和分子机理的研究还十分欠缺.本文简略综述了类黄酮物质的结构、分布、功能、CHS基因在类黄酮途径中的重要作用、植物界CHS基因克隆和基因工程的研究进展,重点论述了CHS在油菜的种皮色泽、花瓣颜色、异花传粉、花粉育性、抗紫外线能力、茎表紫色、抗病能力等性状形成中可能的重要作用,并提出了通过对CHS基因的表达调控来改良这些性状的可能性.     

水稻香豆酸辅酶A连接酶基因的分子克隆及一级结构分析

 香豆酸：辅酶A连接酶（4CL）是类黄酮生物合成过程中的关键酶之一。本文以水稻为材料分离、克隆了4CL基因，并测定了该基因的一级结构。水稻4CL基因含有5个外显子，共编码563个氨基酸。外显子/内含子交界顺序和多数已报道的其他植物基因相似，边界剪切位点符合GT-AG规则。编码区中同义密码有明显的偏态使用现象，导致整个编码顺序GC含量升高。在非编码区，除了有5'端真核生物基因启动转录所必需的TATA盒以及3'-端mRNA多A加尾信号之外，在TATA盒的上游有一个在碱基顺序和位置上都十分类似于“光盒”的结构。     

模拟移动床色谱分离玉米须粗提物

在无标样的情况下,应用模拟移动床色谱分离玉米须粗提物,并得到含量为92%的产品。经液质、红外、紫外鉴定为黄酮类。     

不同产地不同部位三七中总黄酮的含量测定

[目的]考察三七不同产地不同部位总黄酮含量。[方法]采用紫外分光光度法测定不同产地不同部位三七总黄酮的含量。[结果]不同产地三七中总黄酮含量存在一定差异;不同部位三七中总黄酮含量差异显著,大小顺序依次为茎叶(1.77%)花(1.43%)根茎(0.50%)须根(0.34%)主根(0.19%)。[结论]三七地上部分总黄酮含量明显高于地下部分,为三七资源的综合开发利用奠定基础。     

银杏叶总黄酮的负压沸腾提取工艺1）

以银杏叶为原料,在单因素试验的基础上,采用响应面分析法对影响负压沸腾提取银杏叶总黄酮得率的主要因素（提取压力、V（60％乙醇）∶m（银杏叶干粉）和提取时间）进行优化,建立了影响因素与总黄酮之间的函数关系。结果表明：10 g银杏叶干粉,负压提取最佳工艺条件为提取压力－0．08 MPa,提取时间70 min,提取温度50℃,V（60％乙醇）∶m（银杏叶干粉）＝10 mL∶1 g ,提取2次,银杏叶总黄酮提取率为93．55％。与传统提取法相比（提取率为81．69％）,负压沸腾提取温度降低了30℃,提取时间减少了42％。     

天山雪莲SikP基因提高类黄酮质量分数的研究

通过分子克隆技术人工调控天山雪莲类黄酮代谢过程,以提高其类黄酮质量分数。采用农杆菌介导法将SikP基因的植物表达载体转入天山雪莲叶片,成功获得转SikP基因天山雪莲抗性愈伤组织及从生芽;提取并检测对照组和转SikP基因天山雪莲的类黄酮,结果显示,转SikP基因天山雪莲的类黄酮质量分数明显提高,是对照组天山雪莲类黄酮质量分数的9.63倍。说明,天山雪莲Myb转录调控因子SikP基因对天山雪莲次生代谢具有重要的调控作用,能够有效地提高天山雪莲类黄酮的质量分数。     

Phytocomplexes from liquorice (Glycyrrhiza glabra L.) leaves--chemical characterization and evaluation of their antioxidant, anti-genotoxic and anti-inflammatory activity

Three extracts of different polarities of Glycyrrhiza glabra L. leaves were characterized and evaluated for their antioxidant, anti-genotoxic and anti-inflammatory activity. In total, thirty components have been identified and quantified through the use of liquid chromatography (LC) with ultraviolet-visible diode-array-detector (UV-vis-DAD) and mass spectrometry (MS). The main components belong to the polyphenols family, being flavonoid and dihydrostilbene derivatives. The extracts have been investigated for their antioxidant, anti-genotoxic and anti-inflammatory activities, which are fundamental requirements of efficacious chemo-preventive agents. The ethyl acetate extract proved to be the most valuable, evidently for the conspicuous presence of several polyphenols, namely flavonoids and dihydrostilbenes.     

Inhibition of P-glycoprotein ATPase and its transport function of Helicoverpa armigera by morin, quercetin and phloroglucinol

Flavonoids (morin, quercetin and phloroglucinol) were tested for their ability to modulate the function of P-glycoprotein ATPase of the insecticide resistant pest Helicoverpa armigera (Ha-Pgp). Flavonoids in the presence of ethylparaoxon or cypermethrin significantly reduced both larval weight as well as survival rate 40-50%. Morin and quercetin inhibited the activity of Ha-Pgp ATPase by 80-90%, whereas phloroglucinol inhibited ATPase activity by 40% at 100 μM concentration. These flavonoids inhibited the verapamil, ethylparaoxon and cypermethrin-stimulated Ha-Pgp ATPase activity. Morin, quercetin and phloroglucinol binding were quantitated by quenching of the intrinsic Trp fluorescence of purified Ha-Pgp ATPase. Drug transport was monitored in proteoliposomes containing Ha-Pgp ATPase using the high affinity fluorescent substrate tetramethylrosamine (TMR) in real time. Addition of the morin and quercetin mediated the collapse of the TMR concentration gradient generated by Ha-Pgp ATPase. The inhibition studies on Ha-Pgp ATPase activity may contribute towards understanding new strategies of the pest to overcome insecticide resistance.