鲁山冬凌草戊素的结构

从鲁山冬凌草叶中分得一个新的二萜化合物,鲁山冬凌草戊素(lushanrubesensin E),其结构经各项光谱数据确定为对映-2α,11β-二羟基-3α,6β-二乙酰氧基-16-贝壳杉烯-15-酮。     

鲁山冬凌草乙素和丙素的结构研究

从河南省鲁山县产冬凌草叶中分得两个新的对映-贝壳杉烯型二萜化合物,命名为鲁山冬凌草乙素和丙素,经光谱和化学方法证明,它们的结构分别为(1)和(2)。     

冬凌草最佳采收期的研究

以冬凌草的分枝数、单墩叶重及叶中冬凌草甲素的含量作为冬凌草药材产量和质量的评价指标,确定了河南淇县野生冬凌草和湖北广水、武汉野转家种冬凌草的最佳采收期,并分析了气象因素对冬凌草药材质量和产量的影响。结果表明：气象因素对引种地与原产地冬凌草的质量没有明显影响,药材叶中冬凌草甲素含量均在6月份左右达到峰值且十分接近;但气象因素对冬凌草产量则有影响,气候不同导致引种地野转家种药材的分枝数比原产地野生药材多2～4倍。综合质量和产量的考察结果,冬凌草的最佳采收期应定在其开花前,引种地武汉宜定在6月份,引种地广水宜定在6～7月份,原产地河南淇县宜定在6～8月份。     

鲁山冬凌草丁素的结构

从河南省鲁山县产冬凌草叶中分得一个新的对映-贝壳杉烯型二萜化合物,命名为鲁山冬凌草丁素,经光谱和化学方法证明,其结构如(1)式所示。     

冬凌草最佳采收期的研究

以冬凌草的分枝数、单墩叶重及叶中冬凌草甲素的含量作为冬凌草药材产量和质量的评价指标,确定了河南淇县野生冬凌草和湖北广水、武汉野转家种冬凌草的最佳采收期,并分析了气象因素对冬凌草药材质量和产量的影响。结果表明:气象因素对引种地与原产地冬凌草的质量没有明显影响,药材叶中冬凌草甲素含量均在6月份左右达到峰值且十分接近;但气象因素对冬凌草产量则有影响,气候不同导致引种地野转家种药材的分枝数比原产地野生药材多2～4倍。综合质量和产量的考察结果,冬凌草的最佳采收期应定在其开花前,引种地武汉宜定在6月份,引种地广水宜定在6～7月份,原产地河南淇县宜定在6～8月份。     

氮碳源对冬凌草再生植株生长及次生代谢产物的影响

以冬凌草再生植株为研究材料,通过改变培养基中蔗糖浓度及NO3-/NH4+比例,研究冬凌草再生植株的生长状况及植株体内次生代谢物的积累规律.结果表明:3%蔗糖有利于冬凌草再生植株的生长和冬凌草甲素的积累,5%蔗糖有利于迷迭香酸的积累;NO3-/NH4+比例过高或过低均不利于再生植株的生长和次生代谢产物的积累,二者比例为2∶1时再生植株生长和次生代谢产物积累最佳.说明不同蔗糖浓度及NO3-/NH4+比例对冬凌草再生植株的生长和次生代谢物合成有明显的影响.     

冬凌草水溶性化学成分研究

新鲜冬凌草用70％丙酮水溶液组织破碎提取,然后经Diaion HP-20、Toyopearl HW-40、MCI Gd、silica gel等柱层析方法分离得到5个单体化合物,经波谱分析鉴定为α-D-呋喃果糖(1),阿魏酸(2),丹参素甲正丁酯(3),3,4-二羟基苯乳酸(4),延命素-1β-D-吡喃葡萄糖苷(5)。除延命素-1β-D-吡喃葡萄糖苷外,其它4个化合物均为首次从冬凌草及其同属植物中分离得到。     

冬凌草甲素抗炎作用参与多种疾病治疗的新进展

冬凌草甲素是冬凌草的主要活性成分,具有广泛的药理作用。研究表明,冬凌草甲素在炎症性疾病方面表现出较好的疗效。综述国内外关于冬凌草甲素抗炎作用参与多种疾病治疗的研究进展,并分析研究的方向,为研究与开发以冬凌草为原料的抗炎新药提供参考。     

冬凌草素抗肿瘤机制研究进展

冬凌草是一种颇具研究价值的药用植物,其有效活性成分冬凌草甲素、乙素具有多种药理作用,尤其是抗肿瘤活性。本文拟对其化学成分、药理作用和抗肿瘤分子机制研究方面作一综述,冬凌草的药用价值值得进一步研究、开发、利用。     

冬凌草中一个苯丙醇酯新化合物

通过多种色谱手段,从冬凌草95％乙醇提取物中分离得到一个新化合物。运用多种波谱技术（1D、2D—NMR和MS）,该新化合物鉴定为2-氨基-3-苯丙基2-苯甲酰氨基-3-利胆醇酯（苯丙醇酯）。     

Synthesis and nuclear magnetic resonance study of 3-dehydroecdysteroids

Several 3-dehydro- (or 3-oxo-) ecdysteroids have been prepared by enzymatic and/or chemical means. Methods for their purification using various high-performance liquid chromatography systems are described. Proton and carbon nuclear magnetic resonance analyses show that 3-dehydroecdysteroids when dissolved in water or methanol (but not in chloroform) present a temperature-dependent equilibrium between two forms. The possible structure of these two forms is discussed.     

Systematic crosstalk in plasmalogen and diacyl lipid biosynthesis for their differential yet concerted molecular functions in the cell

Plasmalogen is a major phospholipid of mammalian cell membranes. Recently it is becoming evident that the sn-1 vinyl-ether linkage in plasmalogen, contrasting to the ester linkage in the counterpart diacyl glycerophospholipid, yields differential molecular characteristics for these lipids especially related to hydrocarbon-chain order, so as to concertedly regulate biological membrane processes. A role played by NMR in gaining information in this respect, ranging from molecular to tissue levels, draws particular attention. We note here that a broad range of enzymes in de novo synthesis pathway of plasmalogen commonly constitute that of diacyl glycerophospholipid. This fact forms the basis for systematic crosstalk that not only controls a quantitative balance between these lipids, but also senses a defect causing loss of lipid in either pathway for compensation by increase of the counterpart lipid. However, this inherent counterbalancing mechanism paradoxically amplifies imbalance in differential effects of these lipids in a diseased state on membrane processes. While sharing of enzymes has been recognized, it is now possible to overview the crosstalk with growing information for specific enzymes involved. The overview provides a fundamental clue to consider cell and tissue type-dependent schemes in regulating membrane processes by plasmalogen and diacyl glycerophospholipid in health and disease.     

黄牛木属植物的化学成分与生物活性研究进展

本文综述了从1963年以来黄牛木属植物的化学成分和生物活性研究,概括了该属植物中部分口山酮和蒽醌化合物的NMR数据。     

珙桐叶中喹啉类生物碱甙——pumiloside结构鉴定

首次从珙桐叶甲醇提取物的水溶性部分得到一配糖体化合物-喹啉类生物碱甙(pumiloside),它是抗肿瘤物质喜树碱的生物合成前体。本文对其结构进行鉴定。     

Determining the optimal size of small molecule mixtures for high throughput NMR screening

High-throughput screening (HTS) using NMR spectroscopy has become a common component of the drug discovery effort and is widely used throughout the pharmaceutical industry. NMR provides additional information about the nature of small molecule-protein interactions compared to traditional HTS methods. In order to achieve comparable efficiency, small molecules are often screened as mixtures in NMR-based assays. Nevertheless, an analysis of the efficiency of mixtures and a corresponding determination of the optimum mixture size (OMS) that minimizes the amount of material and instrumentation time required for an NMR screen has been lacking. A model for calculating OMS based on the application of the hypergeometric distribution function to determine the probability of a hit for various mixture sizes and hit rates is presented. An alternative method for the deconvolution of large screening mixtures is also discussed. These methods have been applied in a high-throughput NMR screening assay using a small, directed library.     

Improved frequency resolution in multidimensional constant-time experiments by multidimensional Bayesian analysis

Summary The resolution of spectral frequencies in NMR data obtained from discrete Fourier transformation (DFT) along D constant-time dimensions can be improved significantly through extrapolation of the D-dimensional free induction decay (FID) by multidimensional Bayesian analysis. Starting from Bayesian probability theory for parameter estimation and model detection of one-dimensional time-domain data [Bretthorst, (1990) J. Magn. Reson., 88, 533–551; 552–570; 571–595], a theory for the D-dimensional case has been developed and implemented in an algorithm called BAMBAM (BAyesian Model Building Algorithm in Multidimensions). BAMBAM finds the most probable sinusoidal model to account for the systematic portion of any D-dimensional stationary FID. According to the parameters estimated by the algorithm, the FID is extrapolated in D dimensions prior to apodization and Fourier transformation. Multidimensional Bayesian analysis allows for the detection of signals not resolved by the DFT alone or even by sequential one-dimensional extrapolation from mirror-image linear prediction prior to the DFT. The procedure has been tested with a theoretical two-dimensional dataset and with four-dimensional HN(CO)CAHA (Kay et al. (1992) J. Magn. Reson., 98, 443–450) data from a small protein (8 kDa) where BAMBAM was applied to the ¹³C and H constant-time dimensions.To whom correspondence should be addressed.     

Computer-assisted assignment of multidimensional NMR spectra of proteins: Application to 3D NOESY-HMQC and TOCSY-HMQC spectra

Summary An algorithm based on the technique of combinatorial minimization is used for the semi-automated assignment of multidimensional heteronuclear spectra. The program (ALFA) produces the best assignment compatible with the available input data. Even partially misleading or missing data do not seriously corrupt the final assignment. Ambiguous sequences of the possible assignment and all alternatives are indicated. The program can also use additional non-spectroscopic data to assist in the assignment procedure. For example, information from the X-ray structure of the protein and/or information about the secondary structure can be used. The assignment procedure was tested on spectra of mucous trypsin inhibitor, a protein of 107 residues.