Hyaluronidase inhibitors from Keiskea japonica

An extract of Keiskea japonica MIQ. showed an inhibitory effect on hyaluronidase activity. From the extract, four new phenylpropanoids, two new maltol glycosides, two new monoterpene glycosides, and two new phenolic compounds were isolated together with 19 known compounds. Among these constituents, two phenylpropanoids and a flavone glucuronide were revealed as hyaluronidase inhibitors.     

Water-soluble constituents of coriander

From the water-soluble portion of the methanol extract of coriander (fruit of Coriandrum sativum L.), which has been used as a spice and medicine since antiquity, 33 compounds, including two new monoterpenoids, four new monoterpenoid glycosides, two new monoterpenoid glucoside sulfates and two new aromatic compound glycosides were obtained. Their structures, were clarified by spectral investigation.     

New Sesquiterpenes from Chloranthus japonicus

Chemical investigation of the roots of Chloranthus japonicus Sieb . has resulted in the isolation and characterization of four new eudesmane‐type sesquiterpenes including two new sesquiterpene cinnamates, along with one new and two known sesquiterpene dimers. Their structures were established by spectroscopic means and by comparison with the respective literature values.     

Water-soluble constituents of ajowan.

From the water-soluble portion of the methanol extract of the fruit of Carum ajowan (ajowan), which has been used as a spice and medicine, 25 compounds, including five new monoterpenoid glucosides, a new monoterpenoid, two new aromatic compound glucosides, and two new glucides, were obtained. Their structures were clarified by spectral investigation.     

Synthesis of thiomorpholino buffers for isoelectric focusing in immobilized pH gradients

The two commercially available Immobilines having a pK of 6.2 (2-morpholino ethyl acrylamide) and 7.0 (3-morpholinopropylacrylamide) have been modified and two new buffers have been synthesized: 2-thiomorpholinoethylacrylamide, pK 6.6, and 3-thiomorpholinopropyl acrylamide, pK 7.4. The replacement of an oxygen with a sulfur atom in the morpholino ring is thus seen to shift the pK values of these two bases by +0.4 pH units. In formulations in which the two new bases replaced the standard morpholino derivatives, identical pH profiles and protein patterns were obtained. The reason for this work was to try to close the gap between the pK 7.0 and 8.5 species and to provide the users of immobilized pH gradients with more buffers in the neutral pH region. The two new thiomorpholino derivatives are an important step in this direction.     

Structures of new flavonoids, erycibenins D, E, and F, and NO production inhibitors from Erycibe expansa originating in Thailand

A new flavanol, erycibenin D, and two new flavans, erycibenins E and F, were isolated from the stems of Erycibe expansa originating in Thailand. The structures of new flavonoids were elucidated on the basis of chemical and physicochemical evidence. In addition, the inhibitory activities of the isolated constituents from E. expansa on lipopolysaccharide-activated nitric oxide production in mouse peritoneal macrophages were examined. Among the principal constituents, two isoflavones, clycosin (IC50 = 13 microM) and erythrinin B (18 microM), and two rotenoids, deguelin (26 microM) and rotenone (27 microM), were found to show potent inhibitory activity.     

单细胞水平的分析方法研究及进展

本文评述了近年来单细胞分析的应用及进展，介绍了超微电极电化学分析法和微柱分离法两大类方法在单细胞分析中应用的机理、必要的技术、有关研究内容和最新进展及其发展方向。     

Novel cytotoxic brominated diterpenes from the red alga Laurencia obtusa

Five new brominated diterpenes, along with two known, have been isolated from the organic extract of the red alga Laurencia obtusa, collected from the coastal rocks of Preveza in the Ionean Sea, Greece. The novel metabolites prevezols B-E possess two new carbon skeletons, to the best of our knowledge, unprecedented in the literature. The structures and the relative stereochemistry of the new natural products were established by means of spectral data analyses. The new metabolites were tested for their cytotoxic activity against five human cell lines. Two metabolites have exhibited significant cytotoxicity.     

A facile synthesis of cyclic bis(3′→5′)diguanylic acid

This paper describes a new method for synthesizing biologically important cyclic bis(3′→5′)diguanylic acid (cGpGp) in a higher yield than that of the existing synthetic method. In the new synthesis, the following two means, in place of those used in the existing synthesis are employed as main strategies to cause the increase in product yield. One of these distinctive strategies in the new synthesis is that the phosphoramidite method is used for the preparation of a key synthetic intermediate of a linear guanylyl(3′→5′)guanylic acid derivative. This method allowed higher-yield formation of the intermediate than that by the triester method used in the existing synthesis. The second distinctive strategy used in the new synthesis is that allyloxycarbonyl and allyl groups are used for the protection of two guanine bases and two internucleotide bonds, respectively. These four allylic protectors can be removed all at once by the organopalladium-catalyzed reaction under neutral conditions. Thus, deprotection of the protected cGpGp precursor was achieved in the present synthesis in a shorter step and under milder conditions than the deprotection achieved in the existing synthesis, which uses diphenylacetyl and o-chlorophenyl groups as protectors for two guanine bases and two internucleotide bonds, respectively, whose full removal requires two different procedures including rather harsh basic treatment. As a result, technical loss and decomposition of the target product in the new synthesis is remarkably reduced.     

New program for molecular calculations with Slater‐type orbitals

A new program for computing all the integrals appearing in molecular calculations with Slater‐type orbitals (STO) is reported. This program follows the same philosophy as the reference pogram previously reported but introduces two main changes: Local symmetry is profited to compute all the two‐electron integrals from a minimal set of seed integrals, and a new algorithm recently developed is used for computing the seed integrals. The new code reduces between one and two orders of magnitude the computational cost in most polyatomic systems. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 81: 148–153, 2001     

Chemical constituents of Taraxacum formosanum

Three new compounds, taraxacine-A (1), taraxacine-B (2) and taraxafolin (3) together with twenty-five known compounds, which include two beta-carboline alkaloids, two indole alkaloids, two chlorophylls, two flavonoids, one coumarin, two triterpenoids, one monoterpenoid, one ionone, four steroids and eight benzenoids, were isolated and characterized from the fresh aerial parts of Taraxacum formosanum. Structures of new compounds were determined by spectral analysis.     

A new sesquiterpene glycoside from the aerial parts of Saussurea triangulata

Column chromatographic separation of a MeOH extract of the aerial parts of Saussurea triangulata led to the isolation of a new sesquiterpene glycoside 6, together with three quinic acid derivatives, two phenolics, two sesquiterpene glycosides and two flavonoids. The new compound 6 was identified as amarantholidol A glycoside by spectroscopic and chemical methods.     

Two new terpenoids from fruits of Ziziphus jujuba

One new ceanothane-type triterpene and one new sesquiterpene,together with two known triterpenes were isolated from the fruits of Ziziphus jujuba Mill.(Rhamnaceae).Based on the spectral analyses,the structures of two new compounds were elucidated as 2α-aldehydo-A(1)-norlup-20(29)-en-27,28-dioic acid(zizyberanal acid)(1),and zizyberanone(2).While the two known triterpenes were identified as zizyberanalic acid(3)and ursofic acid(4).     

A two‐step method for rapid characterization of electroosmotic flows in capillary electrophoresis

The measurement of electroosmotic flow (EOF) is important in a capillary electrophoresis (CE) experiment in terms of performance optimization and stability improvement. Although several methods exist, there are demanding needs to accurately characterize ultra‐low electroosmotic flow rates (EOF rates), such as in coated capillaries used in protein separations. In this work, a new method, called the two‐step method, was developed to accurately and rapidly measure EOF rates in a capillary, especially for measuring the ultra‐low EOF rates in coated capillaries. In this two‐step method, the EOF rates were calculated by measuring the migration time difference of a neutral marker in two consecutive experiments, in which a pressure driven was introduced to accelerate the migration and the DC voltage was reversed to switch the EOF direction. Uncoated capillaries were first characterized by both this two‐step method and a conventional method to confirm the validity of this new method. Then this new method was applied in the study of coated capillaries. Results show that this new method is not only fast in speed, but also better in accuracy.     

Sesquiterpenes and Flavonoids from Serratula Strangulata

Phytochemistry investigation of the whole plants of Serratula strangulata has led to the isolation of two sesquiterpenes, six flavonoids, and two isoflavonoids. Among these, a sesquiterpene and two flavonoids are new compounds. The structures of these new compounds were elucidated by spectroscopic methods and 2D NMR techniques.     

Chemical constituents of a marine soft coral of the genus Lobophytum

Chemical investigations on the marine soft coral Lobophytum sp., collected from the Andaman and Nicobar Islands, yielded two new acyl glycerol monoalkyl ethers along with two known compounds of this series (1a-d), and a new ceramide (4a). The structures of the new and known compounds were elucidated on the basis of extensive spectroscopic studies and chemical reactions.     

Hyloglyceride and hylodiglyceride: two new glyceride derivatives from Hylodendron gabunensis

Phytochemical investigation of Hylodendron gabunensis resulted in the isolation of two new glyceride derivatives, hyloglyceride (1) and hylodiglyceride (2). The structures of the two new compounds were determined by comprehensive analysis of their 1D and 2D NMR spectroscopic, and HREIMS data. One known compound was also isolated and identified as beta-sitosterol.     

Emerging approaches to estimate retention factors in high performance liquid chromatography

The retention factor is one of the most universally used parameters in chromatography. The errors associated with the conventional ways to determine the retention factor of compounds in liquid chromatography are studied and compared with those corresponding to new approaches. The later avoid the use of extra-column time and hold-up time values, which have proven to be tedious and ambiguous. Simulations and real data, used to examine the accuracy of four different approaches (two classic and two new), suggest that the new approaches could be considered more satisfactory than the classic ones.     

具有光致变色和发光性能的有机化合物的合成及其性能研究

以吲哚啉螺苯并吡喃与香豆素衍生物为原料,用D_cC缩合酯化法在温和条件下合成了8种新的具有光致变色和发光性能的化合物,确定了结构,研究了紫外光谱、荧光光谱及光致变色性.所得化合物同时具有光致变色和发荧光的双重特性,而且荧光光谱中有两个激发波长,每一个波长对应产生一个不同的荧光发射峰.     

Terpenoids from the liverwort Chandonanthus hirtellus

A new bicyclogermacrane sesquiterpenoid, two new cembrane diterpenoids and five new dolabellane diterpenoids, along with known terpenoids, have been isolated from the Malaysian liverwort Chandonanthus hirtellus. The structures of the new compounds were established by spectroscopic and chemical methods in addition to X-ray crystallographic studies.