甘草素与异甘草素分离研究

甘草素、异甘草素系甘草中黄酮类化合物，由于它对艾滋病病毒的增殖有抑制作用，故在临床应用及分离手段方面受到普遍重视。因其在甘草中含量较少，国外一般采用高效液相色谱法分离，而国内采用柱层分离法。本文对其薄层条件进行实验探讨。     

甘草素和异甘草素提取的研究

乌拉尔甘草经甲醇浸提、溶剂萃取、聚酰胺柱层析、硅胶柱层析和重结晶等步骤分离到了甘草素和异甘草素。并用紫外光谱、红外光谱、核磁共振谱和质谱对甘草素和异甘草素的化学结构进行了确证。     

异甘草素合成工艺优化及其清除自由基活性研究

对异甘草素的合成工艺进行优化和体外清除自由基活性进行研究。通过间苯二酚、冰醋酸、对羟基苯甲酸合成异甘草素,考察物料比、温度、反应时间对产率的影响,通过紫外分光度法对其清除自由基活性进行研究。酚与酸物料比1∶2.5,240 W微波辐射3 min,2,4-二羟基苯乙酮产率最高为65.75%;当醛酮物质的量比为3∶1,温度控制在120~130℃,回流6 h,异甘草素产率最高为28.10%;反应时间控制20 min,异甘草素加入量为1.00 m L清除DPPH自由基能力最强,为66.4%。异甘草素具有一定的抗自由基活性。     

薄层色谱法在α-苯乙醇合成中的应用

用薄层色谱法对α-苯乙醇合成的产品进行了分离、分析。选择出最佳展开溶剂体系为:己烷:乙酸乙酯=5:3(v/v),用该展开剂可有效地分离反应原料和反应产物。并用柱色谱分离得到了纯的产品。     

RP-HPLC法测定大鼠尿及粪中异甘草素含量

大鼠空腹12h后,灌胃给药异甘草素(剂量4.0mg·kg-1),按拟定时间间隔收集尿液和粪便,HPLC法测定尿和粪便中异甘草素的含量,研究大鼠口服异甘草素以后排泄规律。结果显示异甘草素在尿和粪便中的累积排泄率分别为2.34±0.13%和5.23±0.54%;异甘草素在尿与粪便中的回收率很低,表明异甘草素在体内极易发生代谢转化。     

异甘草素甲苷的合成及抗氧化活性研究

以间苯二酚、冰醋酸、对甲氧基苯甲醛为原料,通过酰化、羟醛缩合反应合成异甘草素甲苷,通过~1HNMR、IR对其结构进行表征,利用其与DPPH自由基溶液的反应考察其抗氧化活性。结果表明,异甘草素标准品对DPPH自由基清除率为43.01%,异甘草素甲苷对DPPH自由基清除率为23.14%。异甘草素甲苷抗氧化活性低于异甘草素,故异甘草素的4位羟基是抗氧化活性有效部位。     

正交实验优化异甘草素超声提取工艺

采用超声法提取乌拉尔甘草中异甘草素,通过乙醇体积分数、液固质量体积比(g/mL)、超声提取时间和提取次数4个因素对异甘草素提取率的影响进行了正交实验,确定超声提取最佳工艺条件为:体积分数80%乙醇,液固质量体积比(g/mL)10∶1,超声20 m in,提取3次,异甘草素的提取率为0.37‰,是乙醇热回流提取的2.06倍,是索氏提取的1.54倍。超声提取浸膏中异甘草素的质量分数为0.55%,是乙醇热回流提取的3.24倍,是索氏提取的1.45倍。结果表明:超声提取甘草中异甘草素具有提取温度低、速度快、提取率高、纯度高等特点。     

异甘草素键合硅胶固定相的合成及应用

以10μm硅胶为基质,异甘草素为配体,采用液相连续反应法及中间体法依次合成了异甘草素键合硅胶固定相ISLSP-Ⅰ和ISLSP-Ⅱ。采用FTIR及SEM对合成的固定相进行表征。将ISLSP-Ⅰ固定相填充于50 mm×10 mm i.d. 1号色谱柱中,将ISLSP-Ⅱ固定相填充于30 mm×10 mm i.d. 2号色谱柱中,系统评价了两种方法合成的固定相的色谱性能。结果表明:两根色谱柱的柱效及峰型均较好,大流速下测试组分的保留主要决定于传质阻力。在甲醇-水体系下,2号色谱柱表现出明显的反相色谱分离机制。合成的固定相稳定性良好,使用6个月后,测试组分在两根色谱柱上的保留时间相对偏差不超过0.9%。2号色谱柱对多组分标准样品及中药提取物均具有良好的分离能力。     

薄层色谱法在药品分析中的应用研究

薄层色谱法的诞生与发展,在我国的药物分析领域中是革命性的,它改变了传统药品质量控制中只凭性状、经验来把握质量的单一模式,使药的质量控制、质量保证及药物作用的理解一步进入到可查的分子水平。本文主要探讨了薄层色谱法在药品分析中的应用。     

异黄樟油素的合成及结构分析

在NaOH与KOH作用下,在220℃以上使黄梓油素异构化,合成了异黄梓油素,转化率达96％,收率达95％,产品纯度99％以上。精制产品中反式异构体含量达95％。产品纯化后得反式异黄梓油素,并进行了IR,HNMR与MS分析,对其他几种合成方法进行了讨论。     

Lipid analysis by quantitative thin-layer chromatography

Techniques for the quantitative analysis of lipids using thin-layer chromatography (TLC) are reviewed. The general procedures are divided into two groups on the basis of whether or not the methods involve the recovery of substances from chromatoplates. Recovery methods are elaborated under detection of spots, recovery of substances and quantification. Methods are described for the recovery of labile compounds from chromatoplates and for the determination of the structures of triglycerides and lecithins. Methods for the direct quantitative analysis of spots on chromatoplates are reviewed. These include measurements of spot size, reflectance, absorbance of transmitted light, and fluorescence. Details of the photodensitometric method, particularly, spot visualization and instrumentation are described. The analysis of lipid classes using a combination of DEAE cellulose chromatography and TLC by the densitomery of charred spots is illustrated.     

Quantitative estimation of esters by thin-layer chromatography

A method for the analysis of fatty esters employing separation by thin-layer chromatography and quantitative determinationvia their hydroxamic acids has been developed. Esters of different types are separated on silica gel plates, the spots or zones are scraped from the plates, the esters are extracted from the silica gel, and the iron hydroxamic acid complexes are formed. The latter are then measured by colorimetry. The method is suitable for analysis of mixtures of ordinary, epoxy, monohydroxy, and dihydroxy fatty esters as well as for mixtures of mono-, di-, and triglycerides. Used in conjunction with gas chromatography this method permits the fatty acid composition of seed oils containing oxygenated fatty acids to be measured in about 3 hours. The amount required for the total analysis is 1 to 10 mg. per determination, depending upon composition. Presented at the Spring Meeting, American Oil Chemists' Society, St. Louis, May, 1–3, 1961. Supported by the Hormel Foundation, the National Institutes of Health (Research Grant H-3559), and the National Dairy Council. Appointment supported by the International Cooperation Administration under the Visiting Research Scientists Program of the U.S.A.     

Quantitative analysis of lipids by thin-layer chromatography

A procedure is described for the quantitative analysis of neutral and phospholipids by thinlayer chromatography (TLC) employing densitometry. The chromatophates are prepared with the usual solvent systems. The spots are charred under standard conditions and analyzed with a Photovolt Corp. densitometer equipped with a special stage designed for holding 20×20 cm chromatoplates. Each spot on the chromatoplate gives a peak of density values which is used for quantitative analysis. Radioactive lipids are analyzed by autoradiography by the densitometry of radiograms of chromatoplates developed from X-ray films. The precision of the method is demonstrated on model mixtures of mono, di-and triglycerides, neural and phospholipids and C¹⁴ labeled lipids. Results of the analysis of several samples of rat liver lipids compared closely to those obtained by silicic acid column chromatography. Supported in part by U. S. Public Health Service. Research Grant HE-05375.     

Some practical aspects of thin-layer chromatography of lipids

This report describes methods for the thin-layer chromatography (TLC) of lipids and some practical aspects of the methods. In order to present some basis for choosing the correct powder for particular separations, some properties of several widely used silica gel powders are compared. The effect of binder material such as calcium sulfate in silica gel is studied. The three systems, silica gel as a polar phase, silver nitrate-impregnated silica gel, and reversed phase systems are described with application to neutral lipids. Also included are the applications of TLC to the polar lipids, such as phospholipids, cerebrosides, sulfatides, sphingomyelin and other glycolipids from various sources. The pitfalls and precautions involved in these separations are discussed in detail.     

Quantitative estimation of isomeric monoglycerides by thin-layer chromatography

A method has been developed for the analysis of isomeric monoglycerides by thin-layer adsorption chromatography. Isomeric monoglycerides are separated on silica gel impregnated with boric acid; a mixed solvent system is used. The interaction of hydroxy compounds with boric acid allows the separation of 1- and 2-monoglycerides which cannot be resolved on silica gel alone. In order to make the method quantitative, the resolved components are charred and their spot densities measured. Glycerol, fatty acids, diglycerides, and triglycerides do not interfere. The method does not induce isomerization. Presented at the AOCS meeting, Chicago, Illinois, October 1964.     

凝胶渗透色谱在酚醛树脂合成中的应用

利用凝胶渗透色谱法(GPC)讨论了流速及酚醛树脂样品浓度等对测试结果的影响,建立了最佳测试条件:流速1 mL/min,样品浓度(6±1)g/L。跟踪测定了碱催化酚醛树脂合成过程中的分子质量及其分布变化情况。结果表明:通过GPC图谱可直观地了解不同合成阶段树脂分子质量及其分布状况,同时GPC谱图可作为判定树脂质量的依据。     

Separation of milk fat triacylglycerols by argentation thin-layer chromatography

Argentation thin-layer chromatography was investigated as a method of obtaining detailed compositional information about milk fat. A modified argentation thin-layer chromatography procedure, developed to optimize the separation of the complex mixture of total milk fat triacylglycerols, provided nine different groups of triacylglycerols, based on both the degree of unsaturation and the total length of fatty acid groups. Fatty acid methyl ester (FAME) analysis was performed to determine the composition of each band. Separation on the basis of chainlength was most pronounced among the fully saturated triacylglycerol groups, as evidenced by the high level of C_4:0 and C_6:0 in bands 7 and 8, respectively. For the cis-monoenoic triacylglycerols, the separation of C_4:0 and C_6:0 was less distinct. The cis,cis dienes and other dienoic, trienoic, or tetraenoic species were principally observed in two bands of retention factor <0.08 on the chromatography plate. Minimal cross-contamination of bands was observed, with the exception of the lowest of the trisaturate bands, band 7, in which trans-monoenes were found to be present. Three samples from different points of the New Zealand dairy season were separated by argentation thin-layer chromatography, and their FAME distributions were measured. In addition to differences in the masses of band extracts from these samples, levels of C_10:0 and C_12:0 in all bands, and levels of monounsaturates in the dienoic and trienoic bands, were found to differ. These changes were generally consistent with a pattern of decreasing fat hardness over the November to March period of a typical dairy season.     

Separation of lipids containing phytanic acid by thin-layer chromatography

Cholesteryl phytanate and triglycerides containing phytanic acid were separated from their normal fatty acid analogs by thin-layer chromatography. The presence of the branched-chain fatty acid makes the lipid less polar, and this effect becomes more pronounced as the number of phytanic acid residues in the triglycerides is increased. Phytanic acid was prepared from commercial phytol by catalytic hydrogenation, followed by catalytic oxidation. It contained 5% pristanic acid.     

Estimation of compound classes in coal hydrogenation liquids by thin-layer chromatography

Compound classes in coal liquids were investigated by thin-layer chromatography coupled with a flame ionization detector (t.l.c.-f.i.d.). Individual t.l.c. peaks for coal liquids were identified as paraffins, aromatics, polar compounds and more strongly polar compounds or asphaltenes in order of increasing R_f values by comparison with specific compounds separated previously by conventional liquid chromatography. Concentrations of compound classes for a series of samples obtained by varying the hydrogenation time were estimated and good agreement was found with the results obtained by the USBM-API 60 liquid chromatography procedure. By using the t.l.c.-f.i.d. method, the relation of distribution of compound classes to the reaction conditions of coal hydrogenation could be derived quantitatively with relative ease.