The separation of enantiomeric sugars by chromatographic methods

This paper has reviewed the number of chromatographic methods by which one may determine the absolute configuration of sugars. Both indirect methods (converting the enantiomeric pair into diastereomers) and direct methods (using chiral stationary phases) have been discussed. Resolving reagents for the indirect methods include chiral hydroxy compounds, chiral amines, and chiral thiols; with subsequent separation of the diastereomers either by gas-liquid chromatography or by high pressure liquid chromatography. Direct methods discussed have exclusively utilized chiral substitution of organopolysiloxane phases for the separation of enantiomeric sugars as volatile derivatives by gas-liquid chromatography.     

Chromatographic and electrophoretic approaches in ink analysis

Inks are manufactured from a wide variety of substances that exhibit very different chemical behaviors. Inks designed for use in different writing instruments or printing methods have quite dissimilar components. Since the 1950s chromatographic and electrophoretic methods have played important roles in the analysis of inks, where compositional information may have bearing on the investigation of counterfeiting, fraud, forgery, and other crimes. Techniques such as paper chromatography and electrophoresis, thin-layer chromatography, high-performance liquid chromatography, gas chromatography, gel electrophoresis, and the relatively new technique of capillary electrophoresis have all been explored as possible avenues for the separation of components of inks. This paper reviews the components of different types of inks and applications of the above separation methods are reviewed.     

基于UPLC-Q-Exactive技术结合OTCML数据库快速分析沙棘的功效成分

为探讨沙棘果茎叶功效成分的整体差异。实验应用超高效液相色谱-四极杆静电场轨道阱高分辨质谱联用技术(UPLC-Q-Exactive)结合中药成分高分辨质谱数据库(OTCML),对沙棘果茎叶的化学成分进行了快速鉴定与比较分析。色谱柱为HypersilGOLDaQ色谱柱(2.1mm×100mm,1.9μm),流动相为0.1%甲酸乙腈(A)-0.1%甲酸水(B)梯度洗脱,流速为0.3mL/min,高分辨质谱采用电喷雾离子源(ESI)正、负离子同时扫描模式。基于OTCML中所包含的1200余种中药化合物对照品的保留时间,分子离子、二级碎片离子谱图信息和文献数据进行结构鉴定。结果共鉴定出沙棘中102个功效成分,包括苷类18个,黄酮类21个,萜类18个,苯丙素类13个,生物碱类6个,挥发成分14个,多酚12个;其中有17个化合物是在沙棘中首次发现,对沙棘果茎叶比较表明这些功效成分在不同部位分布有明显差异。该方法为今后充分开发利用沙棘资源提供了基础数据,也为沙棘相关产品的质量控制和药效物质基础研究奠定了基础。     

Analytical methods to determine phytoestrogenic compounds

The analytical methods for the determination of phytoestrogenic compounds in edible plants, plant products and biological matrices are reviewed. The detection, qualitative and quantitative methods based on different chromatographic separations of gas chromatography (GC), high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) coupled with various detections by ultraviolet absorption (UV), electrochemical detection (ED), fluorescence detection, mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR), as well as non-chromatographic immunoassay are each extensively examined and compared. An overview on phytoestrogen chemistry, bioactivities and health effects, plant precursors, metabolism and sample preparation is also presented.     

Untersuchung von Bestandteilen der Zuckerrübenmelasse,die auf Aspergillus niger bei der Citronensäureproduktion toxisch wirken

Several fractions of ether extracts of beet molasses separated by chemical and chromatographic methods were found to be toxic for Aspergillus niger. Addition of these fractions to growth medium caused sinking of the mycelium in the culture broth and irregular growing of the test strains. Fermentation tests carried out on molasses media in the presence of the toxic fractions showed a different susceptibility depending on the used strain. From one fraction n-alkanes with 16 to 36 carbon atoms were isolated by thin-layer chromatography and identified using IR and GC methods. These compounds originated in molasses probably from chemical additives used in the sugar manufacture plant.     

Volatile compounds of healthy and insect-damaged Hippophae rhamnoides sinensis in natural and planted forests

Volatile compounds of healthy and insect-damaged stems of Hippophae rhamnoides sinensis were analysed using dynamic headspace and thermal-desorption cold-trap injector gas chromatography/mass spectroscopy (TCT-GC/MS). Sixteen compounds, belonging to alkanes, alcohols, aldehydes, esters, ketones, and ethers, were identified in the stems of healthy H. rhamnoides sinensis; the compounds in H. rhamnoides sinensis occurring naturally or cultivated in plantations were similar, but the relative contents were significantly different. In plants damaged by Holcocerus hippophaecolus, the nature and content of the volatile compounds were greatly changed. Butanedione and butyl glyoxylate were newly generated after damage by the pest, and the relative levels of pentanal, heptanal, eucalyptol, terpineol, and camphor were sharply increased in both naturally occurring and plantation-grown plants. n-Decane, trans-2-nonen-1-ol, and n-hexadecane levels increased in plants cultivated in the plantation and decreased in natural forests, whereas the levels of other types were reduced. Thus, both the nature and the content of volatile compounds of H. rhamnoides sinensis are affected by H. hippophaecolus damage, providing a theoretical basis to identify the mechanism of pest destruction.     

Chromatographic methods for the determination of toxicants in faeces

Modern chromatographic techniques and their application in the determination of toxic compounds in faeces are reviewed. Faecal analysis may be of importance in toxicokinetic studies of xenobiotics in order to determine factors such as metabolism, body burden and major routes of elimination. Compounds of interest include various food constituents, drugs and occupational or environmental factors. Further, various mutagenic or carcinogenic compounds which are excreted by faeces have been indicated to represent risk factors for colorectal cancer. In this context, the chromatographic determination of the endogenously generated fecapentaenes and bile acids, both postulated etiological factors in colorectal carcinogenesis, is reviewed. For fecapentaene determination, several high-performance liquid chromatographic (HPLC) methods are available; however, the applicability of some of these methods is limited owing to insufficient separation of various isomeric forms or discrimination between fecapentaenes and their precursors. For the determination of bile acids in faeces, many chromatographic procedures have been reported, and the characteristics of the most relevant methods are compared and discussed. It is concluded that separation by gas chromatography (GC) in combination with mass spectrometry provides the highest selectivity and sensitivity. A relatively rapid alternative analysis for the determination of total and aqueous faecal bile acids is proposed. Further, methods for the determination of polycyclic aromatic hydrocarbons (PAHs) are reviewed. Although the use of radiolabelled PAHs in animal studies has many advantages, it cannot be applied for human biological monitoring and HPLC and GC provide sensitive alternatives. An HPLC method for the determination of non-metabolized PAHs in faeces is described.     

Advances in techniques for ecdysteroid analysis

Summary

Recent improvements in chromatographic methods for ecdysteroids are reviewed. Minor improvements in liquid chromatography have increased the separation and range of compounds which can be accomodated, some useful techniques have been introduced in thin layer chromatography, and with new radioactivity scanners and direct mass spectrometry from TLC, this technique retains an important place among the tools of the ecdysonist. Supercritical fluid chromatography has been suggested as a rapid and more sensitive alternative to liquid chromatography. In mass spectrometry, fast atom bombardment has proved most useful, though coupling HPLC through thermospray and ptasmaspray methods has been attempted, but as yet, these techniques lack sensitivity. New solid phase immunoassay methods using colorimetric rather than radioactivity measurements promise to give a better means of analysis of small amounts of ecdysteroids, capable of use in the presence of radiolabeled compounds. A solid phase separation of C-20, 22 diol ecdysteroids with immobilized phenylboronic acid has been reported.     

Chromatographic analysis of carotenol fatty acid esters in Physalis alkekengi and Hippophae rhamnoides

The carotenol fatty acid esters of two potentially valuable sources of plant carotenoids, sepals of Physalis alkekengi (Chinese lantern) and fruits of Hippophae rhamnoides (sea buckthorn), were separated by column chromatography and identified by HPLC-DAD and HPLC-MS. A chemical and an enzymatic hydrolysis were employed to identify the parent carotenoids and to remove the lipid components. Zeaxanthin and beta-cryptoxanthin esters represented the main fraction in P. alkekengi sepals and an important one in H. rhamnoides fruits. Beta-Cryptoxanthin palmitate and zeaxanthin dipalmitate were identified as major compounds in both plants. In P. alkekengi, the carotenoids were mainly (> 90%) esterified with palmitic acid, and a high proportion (> 80%) of saturated medium chain fatty acids was found (by GC-MS) in the total lipid extract. Although the total lipid extract of H. rhamnoides contained significant amounts of unsaturated fatty acids, especially oleic and palmitoleic acids, the xanthophylls were mainly esterified with saturated fatty acids. The oleoresins of both species represent potential sources of carotenoid esters and can be used as food additives, cosmetic ingredients or nutraceuticals.     

Chromatographic and electrophoretic methods for pharmaceutically active compounds in Rhododendron dauricum

In this review, chemical constituents present in Rhododendron dauricum L. were briefly surveyed, and the methods of pretreatment of this plant prior to analysis were also summarized. The analysis methods reported for determining pharmaceutically active compounds in R. dauricum L. include gas chromatography with mass spectrscopy, thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). In addition, both advantages and disadvantages of the above methods were mentioned.     

Survey of recent advances in analytical applications of immunoaffinity chromatography

Methods that use immunoaffinity chromatography (IAC) for sample preparation or detection are becoming increasingly popular as tools in the analysis of biological and nonbiological compounds. This paper presents an overview of immunoaffinity chromatography and examines some recent developments of this technique in analytical applications. The emphasis is placed on HPLC-based IAC methods or those that combine IAC with other instrumental techniques; however, novel approaches that employ low-performance IAC columns for chemical quantitation are also considered. Particular applications that are examined include (1) the use of IAC in the direct detection of analytes, (2) the extraction of samples by IAC prior to on- or off-line detection by other methods, (3) the use of IAC in chromatographic-based immunoassays, and (4) the development of postcolumn reactors based on IAC for the detection of analytes as they elute from other types of chromatographic columns. The advantages and limitations for each approach are considered. In addition, a summary is provided of reports in the literature that have used IAC for these various formats.     

Three new anti-proliferative Annonaceous acetogenins with mono-tetrahydrofuran ring from graviola fruit (Annona muricata)

Bioassay-guided fractionation of the fruit powder of graviola (Annona muricata) yielded three novel compounds: muricins J, K, and L. The compounds are all C35 Annonaceous acetogenins with a mono-tetrahydrofuran ring and four hydroxyls. Their structures were elucidated by spectral methods and chemical modification after isolation via chromatographic techniques and HPLC purification. These three acetogenins demonstrated an antiproliferative against human prostate cancer PC-3 cells.     

Sesquiterpene constituents from the essential oil of the liverwort Plagiochila asplenioides

The essential oil of the liverwort Plagiochila asplenioides from two different locations in Northern Germany were investigated by chromatographic and spectroscopic methods. Seven compounds were isolated by preparative gas chromatography (GC) and their structures investigated by mass spectrometry (MS), NMR techniques and chemical correlations in combination with enantioselective GC. In addition to known constituents, aromadendra-1(10),3-diene, two aromatic sesquiterpene hydrocarbons, bisabola-1,3,5,7(14)-tetraene and bisabola-1,3,5,7-tetraene, three sesquiterpene ethers, muurolan-4,7-peroxide, plagiochilines W and X, in addition to ent-4-epi-maaliol, could be identified as natural compounds for the first time.     

High-performance liquid chromatographic separation of fluoroquinolone enantiomers: a review

Fluoroquinolones are antibacterial agents widely used clinically. In recent years, there has been an important development of new derivatives, and more than 7000 analogues have been described today. Different fluoroquinolones (FQ) have one or two chiral centers in their chemical structure and are available as racemates, diastereoisomers, or pure enantiomers. The clinical and pharmaceutical uses of these compounds need effective analytical procedures for quality control and pharmacodynamic and pharmacokinetic studies. This review article focuses on the high-performance liquid chromatographic separation of fluoroquinolone stereoisomers by the use of derivatization methods and ligand exchange (LE) or chiral liquid chromatography.     

毛药忍冬花蕾抗氧化活性部位化学成分研究

毛药忍冬(Lonicera serreana)为忍冬属(Lonicera)植物,其花和果实入药,具有清热解毒、凉散风热之功效,但至今缺乏系统化学成分及药理活性研究。为了寻找毛药忍冬中天然抗氧化活性成分,进一步开发利用忍冬属药用植物资源,该研究以DPPH自由基清除法为活性指导,首次对毛药忍冬干燥花蕾75%乙醇提取物的不同极性萃取部位进行抗氧化活性测试,结果发现乙酸乙酯萃取物表现出最强的抗氧化活性(平均清除率为89.45%)。进一步应用现代色谱手段(硅胶柱色谱、Sephadex LH-20凝胶柱色谱等),从毛药忍冬花蕾的乙酸乙酯萃取物中分离单体化合物,运用现代光谱分析技术(MS、1 H-NMR、13 C-NMR、COSY、HSQC、HMBC、ROESY),并结合文献数据鉴定化合物的化学结构。结果表明:从毛药忍冬干燥花蕾75%乙醇提取物中共分离得到9个化合物,分别鉴定为4个酚酸类化合物:绿原酸(1)、绿原酸甲酯(2)、绿原酸乙酯(3)、咖啡酸(4);4个黄酮类化合物:木犀草素(5)、木犀草素-7-O-β-D-葡萄糖苷(6)、槲皮素(7)、槲皮素-3-O-β-D-葡萄糖苷(8);1个甾醇类化合物:β-谷甾醇(9)。所有化合物均为从毛药忍冬花蕾中首次分离得到。研究结果可为抗氧化类相关产品的开发提供科学依据。     

Analytical methods in bioassay-directed investigations of mutagenicity of air particulate material

The combination of short-term bioassays and analytical chemical techniques has been successfully used in the identification of a variety of mutagenic compounds in complex mixtures. Much of the early work in the field of bioassay-directed fractionation resulted from the development of a short-term bacterial assay employing Salmonella typhimurium; this assay is commonly known as the Ames assay. Ideally, analytical methods for assessment of mutagenicity of any environmental matrix should exhibit characteristics including high capacity, good selectivity, good analytical resolution, non-destructiveness, and reproducibility. A variety of extraction solvents have been employed in investigations of mutagenicity of air particulate; sequential combination of dichloromethane followed by methanol is most popular. Soxhlet extraction has been the most common extraction method, followed by sonication. Attempts at initial fractionation using different extraction solvents have met with limited success and highlight the need for fractionation schemes applicable to moderately polar and polar mutagenic compounds. Fractionation methods reported in the literature are reviewed according to three general schemas: (i) acid/base/neutral partitioning followed by fractionation using open-column chromatography and/or HPLC; (ii) fractionation based on normal-phase (NP) HPLC using a cyanopropyl or chemically similar stationary phase; and (iii) fractionation by open-column chromatography followed by NP-HPLC. The HPLC methods may be preparative, semi-preparative, or analytical scale. Variations based on acid/base/neutral partitioning followed by a chromatographic separation have also been employed. Other lesser-used approaches involve fractionation based on ion-exchange and thin-layer chromatographies. Although some of the methodologies used in contemporary studies of mutagenicity of air particulate do not represent significant advances in technology over the past 30 years, their simplicity, low cost, effectiveness, and robustness combine to result in their continued application in modern laboratories.     

Analytical methods for the quantitative determination of selective serotonin reuptake inhibitors for therapeutic drug monitoring purposes in patients

Five selective serotonin reuptake inhibitors (SSRIs) have been introduced recently: citalopram, fluoxetine, fluvoxamine, paroxetine and sertraline. Although no therapeutic window has been defined for SSRIs, in contrast to tricyclic antidepressants, analytical methods for therapeutic drug monitoring of SSRIs are useful in several instances. SSRIs differ widely in their chemical structure and in their metabolism. The fact that some of them have N-demethylated metabolites, which are also SSRIs, requires that methods be available which allow therapeutic drug monitoring of the parent compounds and of these active metabolites. Most procedures are based on prepurification of the SSRIs by liquid-liquid extraction before they are submitted to separation by chromatographic procedures (high-performance liquid chromatography, gas chromatography, thin layer chromatography) and detection by various detectors (UV, fluorescence, electrochemical detector, nitrogen-phosphorus detector, mass spectrometry). This literature review shows that most methods allow quantitative determination of SSRIs in plasma, in the lower ng/ml range, and that they are, therefore, suitable for therapeutic drug monitoring purposes of this category of drugs.     

牛蒡根化学成分研究

从牛蒡根95%乙醇提取液中分离得到6个化合物,通过理化性质和波谱学方法鉴定出5个化合物分别为牛蒡子苷(1)、山柰酚(2)、腺苷(3)、羟基茄碱(4)、spirosl-3-O-α-L-rhamnopyrannosyl-(1→4)-O-β-D-galactopyr-anosyl(5),其中化合物2～5为首次从该种植物中分离得到。