960 resultados para Gel permeation chromatography
Resumo:
本论文由三章组成。第一、二章分别报道钩藤、蹄叶橐吾的化学成分研究工作。从两种药用植物中共分离和鉴定了37 个化合物,其中有1 组6 个新的骨架相似的鞘糖脂类同系物及5 个新的倍半萜类化合物。第三章概述了艾里莫芬烷内酯类化合物的研究进展。 第一章报道钩藤(Uncaria rhynchophylla)带钩茎枝乙醇提取物的化学成分。采用正、反相硅胶柱层析等分离方法,运用NMR、MS 等波谱技术共分离鉴定得到22 个化合物,分属于五环三萜类化合物、鞘糖脂类化合物等,其中有1 组6个新的鞘糖脂类化合物同系物,另外有7 个化合物首次从该植物中分离得到。 第二章报道蹄叶橐吾(Ligularia fischeri)根部乙醇提取物化学成分的分离纯化和结构鉴定。通过正、反相硅胶柱层析等分离纯化和MS、NMR 等波谱解析,共分离鉴定得到18 个化合物,其中5 个是新化合物。它们的结构分别确定为3β-acetyl-6β, 8α, 10β-trihydroxyeremophila-7(11)-en-8, 12-olide (23), 3β-acetyl-8β,10β-dihydroxy-6β-(2-methylbutyryloxy)-eremophilenolide (24), 3β-acetyl-6β, 10β-dihydroxyeremophila-7(11), 8(9)-dien-8, 12-olide (25), 3β-acetyl-6β, 10β-dihydroxyeremophila- 7(11), 8(9)-dien-8, 12-olide (26), (3aR, 4R, 5S, 7aS)-2-acetyl-7ahydroxy-3a, 4, 5, 6, 7, 7a-hexahydro-1H-inden-5-yl acetate (27)。这5 个化合物经体外生物活性测试,结果表明化合物23 具有抑制酪氨酸磷酸酯酶的活性, 其IC50 值为1.30 μg/ml。 第三章概述了近二十年来艾里莫芬烷内酯类化合物的研究进展,包括其结构及药理活性两个方面,列举了从23 种植物中分到的114 个艾里莫芬烷内酯类化合物,同时也对其主要生物活性进行了总结。 This dissertation consists of three chapters. The first and second chapters elaborate the phytochemical investigation of Uncaria rhynchophylla and Ligularia fischeri. Thirty-seven compounds, including six new ones, were isolated and identified by spectroscopic methods and X-ray diffraction experiments. The third chapter is a review on the study progress of Eremophilanolides. The first chapter focus on the isolation and identification of chemical constituents from Uncaria rhynchophylla. Twenty-two compounds were isolated from the roots of U. rhynchophylla by repeat column chromatography over normal and reversed phase silica gel. Those compounds mainly belonged pentacyclic triterpenoids and sphingolipids. Among them, a series homologues of six sphingolipids were new compounds and seven compounds were firstly reported in this plant. The second chapter is about the phytochemical investigation of L. fischeri. Eighteen compounds were isolated and identified. Among them, four new erem-ophilanolides and a new dinoreremophilane derivative were characterized as 3β-acetyl-6β, 8α, 10β-trihydroxyeremophila-7(11)-en-8, 12-olide (23), 3β-acetyl-8β, 10β-dihydroxy-6β-(2-methylbutyryloxy)-eremophilenolide (24), 3β-acetyl-6β, 10β-dihydroxyeremophila-7(11), 8(9)-dien-8,12-olide (25), 3β-acetyl-6β, 10α-dihydroxyeremophila- 7(11), 8(9)-dien-8,12-olide (26), (3aR,4R,5S,7aS)-2-acetyl-7a-hydroxy-3a, 4, 5, 6,7, 7a-hexahydro-1H-inden-5-yl acetate (27) by spectroscopic analysis and confirmed by X-ray crystallography analysis. It was revealed that compound 23 has the ability to inhabit the PTP1B in vivo. And its IC50 is 1.30 μg/ml. The third part is a review on the study progress of Eremophilanolides.
Resumo:
本论文由三章组成。第一章介绍了中药蜘蛛香的化学成分的研究成果,第二章为羧甲基魔芋葡苷聚糖-壳聚糖为细胞膜的天冬酰胺酶人工细胞的研究,第三章综述了人工细胞在生物医学领域的应用。 第一章报道了中药蜘蛛香(Valeriana wallichii)根部乙醇提取物的化学成分,采用正、反相硅胶层析等分离方法和MS、NMR等多种波谱手段,从中共分离鉴定出17个化合物,分别为缬草素(valtrate,1),valechlorine(2),homobadrinal(3),baldrinal(4),乙酰缬草素(acevaltrate 5),valeriotetrate C(6),valeriotetrate B(7),对羟基苯乙酮(4'-hydroxy-acetophenone 8),7-hydroxy valtrate(9),8-methylvalepotriate(10),1,5-dihydroxy-3,8-epoxyvalechlorine A(11),二氢缬草素(didrovaltrate 12),胡萝卜苷(13),橙皮苷 (hesperidin 14),prinsepiol-4-O-β-D-glucopyranoside(15),longiflorone(16),乙基糖苷(17)。其中化合物6、7、10、和11为新化合物,化合物9、15、16为首次从该植物中得到。新化合物11为含有氯原子的刚性骨架环烯醚萜,并且确定了其绝对构型。 第二章报道了以羧甲基魔芋葡苷聚糖(CKGM)和壳聚糖(CS)为膜的固定化L-天冬酰胺酶人工细胞研究成果。利用羧甲基魔芋葡苷聚糖和壳聚糖两种生物相容性很好的天然多糖之间的静电吸引力,在非常温和的条件下制备成具有半透过性膜的人工细胞,将治疗儿童急性成淋巴细胞性白血病(ALL)的药物L-天冬酰胺酶包裹在内。通过考察温度和pH对人工细胞的影响,结果表明以CKGM- CS为膜的L-天冬酰胺酶人工细胞对温度和pH的稳定性和耐受性均高于自由酶,说明CKGM-CS对酶具有保护作用,而且小分子底物和产物可以自由进出膜内外,而包裹在膜内的生物大分子则不能泄露出来。 第三章综述了微囊化人工细胞的研究进展。 This dissertation consists of three parts. In the first part, the chemical constituents from the root of Valeriana wallichii were reported. In the second part, preparation and characteristics of L-Asparaginase Artificial cell were reported. The third part is a review on progress of microcapsule artificial cell. The first chapter is about the isolation and identification of the chemical constituents from the root of V. wallichii. Seventeen compounds were isolated from the ethanol extract of roots of V. wallichii through repeated column chromatography on normal and reversed phase silica gel. By the spectroscopic and chemical evidence, their structures were elucidated as valtrate (1), valechlorine (2), homobadrinal (3), baldrinal (4), acevaltrate (5), valeriotetrate C (6), valeriotetrate B (7), 4'-hydroxy-acetophenone (8), 7-hydroxy valtrate (9), 8-methylvalepotriate (10), 1,5-dihydroxy-3,8-epoxyvalechlorine A (11), didrovaltrate (12), daucosterol (13), hesperidin (14), prinsepiol-4-O-β-D-glucopyranoside (15), longiflorone (16), and ethyl glucoside (17). Among them, 6, 7, 10, and 11 are new compounds. 15, 16 and 9 were isolated from this plant for the first time. The absolute configuration of compound 11, an unusual iridoid bearing a C-10 chlor-group and an oxo-bridge connecting C-3 and C-8 resulting in a rigid skeleton, was confirmed. The second chapter is about the semi-permeable microcapsule of carboxymethyl konjac glucomannan-chitosan for L-asparaginase immobilization. Carboxymethyl konjac glucomannan-chitosan (CKGM-CS) microcapsules, which have good biocompatibility, prepared under very mild conditions via polyelectrostatic complexation, were used for immobilize L-asparaginase-a kind of drug for acute lymphoblastic leukemia (ALL). The activity and stability under different temperature and pH of the enzyme loaded-microcapsules were studied. The results indicated the immobilized enzyme has better stability and activity contrasting to the native enzyme. The study illustrates that the L-asparaginase could be protected in CKGM-CS microcapsules, the substrate and product could pass through the system freely.
Resumo:
本学位论文由5 章组成。第1 章报道了两头尖中三萜皂苷类化合物的全扫描电喷雾多级质谱分析及银莲花素A 的电喷雾质谱裂解规律;第2 和3 章报道了两种银莲花属药用植物化学成分的研究结果;第4 章报道了银莲花素A 的化学结构修饰及其对一种蛋白酪氨酸磷酸酯酶(PTP-1B)的抑制活性;第5 章综述了电喷雾质谱在皂苷类化合物结构鉴定中的应用进展。 第1 章报道了运用全扫描电喷雾多级质谱对两头尖中三萜皂苷类化合物的快速定性检测,共检测出18 个准分子离子峰,根据多级质谱数据并结合文献报道,对其中的15 个准分子离子峰进行了归属,并区分了一些同分异构体;更有意思的是,发现了3 个未见文献报道的三萜皂苷类化合物。根据它们的多级质谱数据,对其结构分别进行了初步解析。本章同时对银莲花素A 特殊的质谱裂解途径通过衍生物制备及其质谱分析进行了确认。 第2 和3 章,分别报道了两头尖和打破碗花花中水溶性多糖苷的分离纯化和结构鉴定。采用D101 大孔树脂和反复硅胶柱层析等分离手段,从两头尖水溶性部分分离得到8 个三萜皂苷类化合物,通过红外、电喷雾质谱和核磁共振等现代谱学方法,并结合传统的化学手段鉴定了它们的结构,其中4 个化合物为新化合物,分别命名为多被银莲花皂苷19、多被银莲花皂苷20、多被银莲花皂苷21和多被银莲花皂苷22。从打破碗花花水溶性部位分离得到6 个三萜皂苷类化合物,通过现代谱学手段,并结合传统的化学方法对它们进行了鉴定,其中1 个为新化合物,命名为打破碗花花苷H。 第4 章报道了以银莲花素A 及其同系物为先导化合物,进行化学结构修饰并对修饰产物进行广泛的生物活性筛选,发现在银莲花素A 及其同系物的结构中引入一些酸性基团后,其生物活性发生了变化,一些修饰产物显示出很强的PTP-1B 抑制作用,提示这些化合物有可能用于治疗II 型糖尿病。 第5 章综述了电喷雾多级质谱用于皂苷类化合物结构鉴定的研究进展。 This dissertation composes of five chapters. The first chapter elaborates the detection and qualification of the triterpenoidal saponins in Anemone raddeana by positive and negative full scan ESI-MSn. This part also reports the special fragmentation pathway of Raddeanin A by ESI-MS/MS. The second and third chapters present the phytochemical investigation of two medicinal plants from Anemone. The fourth part dwells on the structure modification of Raddeanin A and their inhibitory activity against PTP-1B. The last part is a review on the progress in the application of ESI-MSn in the structure identification of saponins. The first chapter reports the application of full scan ESI-MSn for fast analysis of triterpenoid saponins in Anemone raddeana. Eighteen quasi- molecular ion peaks were detected in the positive full scan ESI-MS and fifteen of them were identified by analysis of their tandem mass spectral data in the negative ion mode. Several isomers were differentiated. More interesting, three unreported triterpenoid saponins in this medicinal plant were detected and their structures were deduced according to the dissociation pathway of the known triterpenoidal saponins. This chapter also confirms the special fragmentation pathway of Raddeanin A by its derivative and the mass spectral analysis. The second and third chapters expatiate on the isolation and identification of the chemical constituents from A. raddeana and A. hupehensis. Eight compounds were isolated from the roots and stems of A. raddeana by methanol extraction and repeated column chromatography (including D101 and silica gel), and their structures were determined on the basis of IR, ESI-MS, NMR and chemical methods (including acid hydrolysis and alkaline saponification). Among them, four are new triterpenoid saponins and named as Raddeanoside R19, Raddeanoside R20, Raddeanoside R21 and Raddeanoside R22. Six compounds were isolated from the whole plants of A. hupehensis by the same methods as above, and their structures were also determined with the same way. One of them was confirmed to be new triterpenoid saponins and named as hupehensis saponin H. In the fourth chapter, in order to look for new active compounds, the structure of Raddeanin A and its analogs were modified. It was found that the modified products exhibited obvious inhibitory activity against PTP-1B when several acid groups were introduced. The fifth chapter summarizes the progress on the application of ESI-MSn in the structure identification of saponins.
Resumo:
In order to study the gas-phase chemical behavior of transactinides, an on-line isothermal chromatography apparatus has been developed and applied to separate short-lived technetium isotopes in the form of TcO3 from fission products. The fission products from a Cf-252 source were continuously and rapidly transported through the capillary to the isothermal chromatography apparatus using the N-2/KBr gas-jet techniques. Volatile oxide molecules were formed at the reaction zone kept at 900 degrees C since a trace amount of oxygen existed in the N-2 carrier gas. With the new developed isothermal chromatography apparatus, a selective separation of Tc from fission products was achieved. After isothermal chromatographic separation, Tc-101,Tc-103,Tc-104,Tc-105,Tc-106,Tc-107,Tc-108 were dominantly observed together with their Ru daughters in the gamma-spectrum, The chemical yields of Tc-101, and Tc-104 and Tc-105 isotopes with longer half-lives are about 55-57%, and those of Tc-103, Tc-106 and Tc-108 isotopes with shorter half-lives dropped down to 25-28%. The adsorption enthalpy of the investigated compounds on quartz surfaces was determined to be -150 +/- 5 kJ/mol by fitting the measured retention curves with a Monte Carlo model. The observed species of technetium oxide is attributed to TcO3, which is in good agreement with previous experimental results. That means our system worked properly and it can be used to investigate the gas-phase chemical behavior of transactinides.
Resumo:
Gas chromatography-mass spectrometry with electron ionization and positive-ion chemical ionization and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC x GC-TOF-MS) were applied for the characterization of the chemical composition of complex hydrocarbons in the non-polar neutral fraction of cigarette smoke condensates. Automated data processing by TOF-MS software combined with structured chromatograms and manual review of library hits were used to assign the components from GC x GC-TOF-MS analysis. The distributions of aliphatic hydrocarbons and aromatics were also investigated. Over 100 isoprenoid hydrocarbons were detected, including carotene degradation products, phytadiene isomers and carbocyclic diterpenoids. A total of 1800 hydrocarbons were tentatively identified, including aliphatic hydrocarbons, aromatics, and isoprenoid hydrocarbons. The identified hydrocarbons by GC x GC-TOF-MS were far more than those by GC-MS. (C) 2004 Elsevier B.V. All rights reserved.
Resumo:
To avoid the limitation of the widely used prediction methods of soil organic carbon partition coefficients (K-OC) from hydrophobic parameters, e.g., the n-octanol/water partition coefficients (K-OW) and the reversed phase high performance liquid chromatographic (RP-HPLC) retention factors, the soil column liquid chromatographic (SCLC) method was developed for K-OC prediction. The real soils were used as the packing materials of RP-HPLC columns, and the correlations between the retention factors of organic compounds on soil columns (k(soil)) and K-OC measured by batch equilibrium method were studied. Good correlations were achieved between k(soil) and K-OC for three types of soils with different properties. All the square of the correlation coefficients (R-2) of the linear regression between log k(soi) and log K-OC were higher than 0.89 with standard deviations of less than 0.21. In addition, the prediction of K-OC from K-OW and the RP-HPLC retention factors on cyanopropyl (CN) stationary phase (k(CN)) was comparatively evaluated for the three types of soils. The results show that the prediction of K-OC from k(CN) and K-OW is only applicable to some specific types of soils. The results obtained in the present study proved that the SCLC method is appropriate for the K-OC prediction for different types of soils, however the applicability of using hydrophobic parameters to predict K-OC largely depends on the properties of soil concerned. (C) 2004 Elsevier B.V. All rights reserved.
Resumo:
The applicability of on-line coupling of reversed-phase high-performance liquid chromatography to atmospheric pressure ionization tandem mass spectrometry for the separation and characterization of hop acids mixture from the crude extract of Humulus lupulus was investigated. The solvent system consisting of acetonitrile-aqueous formic acid was used to give proper separation of the six main hop bitter acids within 30 min. Further structural information about the components was acquired by collision-induced dissociation (CID). On the basis of analyses of the fragmentation patterns of the major alpha- and beta-bitter acids respectively, identification of the minor ones was performed using selected reaction monitoring (SRM) with a group of qualitatively relevant selected precursor-product ion transitions for each bitter acid in a single high performance liquid chromatography (HPLC) run. Using this technique, six minor hop acids, including "adprelupulone" observed for the first time in natural resources, were detected along with the six major acids. This hyphenated techniques provides potency for rapid qualitative determination of analogs and homologs in mixtures. (C) 2004 American Society for Mass Spectrometry.
Resumo:
The isoflavonoids in Radix astragali were determined and identified by HPLC-photodiode array detection-MS after extraction employing matrix solid-phase dispersion (MSPD). As a new sample preparation method for R. astragali, the MSPD procedure was optimized, validated and compared with conventional methods including ultrasonic and Soxhlet extraction. The amounts of two major components in this herb, formononetin (6) and ononin (2), were determined based on their authentic standards. Four major isoflavonoids, formononetin (6), ononin (2), calycosin (5) and its glycoside (1), and three minor isoflavonoids, (6aR,11aR)-3-hydroxy-9, 10-dimethoxypterocarpan (7), its glycoside (3), and (3R)-7,2'-dihydroxy-3',4'-dimethoxyisoflavone-7-O-beta-D-glycoside (4), were identified based on their characteristic two-band UV spectra and [M + H](+), [aglycone + H](+) and [A1 + H](+) ions, etc. The combined MSPD and HPLC-DAD-MS method was suitable for quantitative and qualitative determination of the isoflavonoids in R. astragali. (C) 2003 Elsevier B.V. All rights reserved.