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白叶香茶菜的化学成分 总被引:4,自引:0,他引:4
从白叶香茶菜(Rabdosia leucophylla(Dunn)Hara)地上部分的乙醇提取物中分离出5个化合物,根据其波谱分析并结合化学方法分别鉴定为:白叶香茶菜戊素(1)、白叶香茶菜己素(2)、信阳冬凌草甲素(3)、maslinic acid(4)和胡萝卜甙(5)。其中1和2为新化合物,2的结构还通过X-单晶衍射得到证实。 相似文献
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从大萼香茶菜叶中又分得一个具有细胞毒活性的新的二萜类化合物,命名为大萼香茶菜丁素(macrocalyxin D)。根据光谱和化学数据鉴定其化学结构为[3]。 相似文献
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胶粘香茶菜(I.glutinosa C.Y.Wu et H.W.Li),为唇形科(Labiatae)香茶菜属(Isodon)植物,产于云南西北部及四川西南部,海拔2000-2300m的河谷两岸山坡砾石地或干燥灌丛中。从云南丽江产胶粘香茶菜中,已分离和鉴定了2种不同结构类型的二萜成分,为进一步比较不同地区产该种植物在化学成分上的差异,我们对大理苍山产胶粘香茶菜进行了研究。由2316g茎叶得149g提取物,然后经硅胶柱层析,依次用氯仿、氯仿-乙酸乙脂(8:2→4:6),乙酸乙酯梯度洗脱,除分离和鉴定了β-谷甾醇(β-sitosterol),胡萝卜甙(β-sitosterol-D-glucoside),乌苏酸(ursolic acid),山植酸(crataegolic acid)和丁二酸(butanedioic acid)外,还得到迄今从香茶菜属植物中分离得到的氧化程度最低的一个对映-贝壳杉烯型四环二萜类化合物:对映-贝壳杉烷-16β,17-二醇(ent—Kauran-16β,17-diol)(1)(2.8g)和具有抑制革兰氏阳性菌生长活性的松香烷(abitane)型二萜pisiferic acid(2)(1.2g)。pisiferic acid(2)系首次从该属植物中得到。 相似文献
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细锥香茶菜二萜的研究 总被引:1,自引:0,他引:1
从四川省峨眉山产细锥香茶菜[Rabdosia coetsa(Buch-Ham,ex,D.Don)Hara]乙醚抽提物中分得了一个新二萜化合物,命名为细锥香茶菜丁素(rabdocoetsin D),其结构经各项波谱数据和化学证据确定为1α,7β-二羟基-11β-乙酰氧基-对映-7β,20-环氧-贝壳杉-16-烯-15-酮(1)。另外还分离到3个已知二萜,细锥香茶菜乙素(rabdocoetsin B)、细锥香茶菜丙素(rabdocoetsin C)、瘿花香茶菜甲素(rosthorin A)。 相似文献
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紫萼香茶菜甲素的结构 总被引:2,自引:1,他引:1
从紫萼香茶菜叶的乙醚提取物中分得一个新的二萜化合物,命名为紫萼香茶菜甲素(rabdoforrestin A),根据波谱和化学证据,其结构为对映-11β-羟基-2α,3α,6β,7α-四乙酰氧基-16-贝壳杉烯-15-酮(ent-11β-hydroxy-2α,3α,6β,7α-tetraacetoxy-16-kauren-15-one)。另外还分离到已知黄酮化合物线蓟素(cirsilioi 4)。 相似文献
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从昆明产腺花香茶菜(Isodon adenanthus (Diels) Kudo)的地上部分分离到8个化合物,通过波谱分析鉴定,化合物1-3为新的对映-贝壳杉烯类二萜化合物,命名为腺花香茶菜素N、0和P;4个已知二萜为白叶香茶菜戊素(4)、无毛狭叶香茶菜素C(5)、腺花香茶菜甲素(6)和白叶香茶菜乙素(7),同时得到一个高度不饱和脂肪酸9,16-二羰基-10,12,14-三烯-十八碳酸(8)。根据ROESY波谱,对化合物4的结构进行了修正。化合物1对K562细胞显示出明显的细胞毒活性(IC50=0.45μg/mL)。 相似文献
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Jean-Pierre Girault Catherine Blais Philippe Beydon Christian Rolando Ren Lafont 《Archives of insect biochemistry and physiology》1989,10(3):199-213
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. 相似文献
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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. 相似文献
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黄牛木属植物的化学成分与生物活性研究进展 总被引:1,自引:0,他引:1
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。 相似文献
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珙桐叶中喹啉类生物碱甙——pumiloside结构鉴定 总被引:2,自引:0,他引:2
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。 相似文献
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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. 相似文献
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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. 相似文献
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Reimond Bernstein Christian Cieslar Alfred Ross Hartmut Oschkinat Jens Freund Tad A. Holak 《Journal of biomolecular NMR》1993,3(2):245-251
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. 相似文献
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