超声辅助乙醇提取龙葵生物总碱的研究

通过正交试验确定传统乙醇溶液提取龙葵生物总碱的最佳提取条件,在此基础上,研究超声辅助乙醇提取龙葵生物总碱的工艺条件,并对提取物龙葵生物总碱进行了定性、定量分析.实验表明:超声辅助乙醇提取龙葵生物总碱,提取率略高于传统提取技术,可节省提取时间和外加能源.     

两个具有新骨架结构的二萜生物碱的质谱研究

利用电子轰击质谱（ＥＩＭＳ）、高分辨质谱（ＨＲＭＳ）和碰撞活化谱（ＣＡＭＳ）等方法研究了两个具有新骨架结构的二萜生物碱的质谱，为其质谱裂解规律性研究提供了依据。     

Does Indole Alkaloid Gramine Confer Resistance in Barley to Aphid Rhopalosiphum Padi?

Accessions of cultivated barley (Hordeum vulgare ssp. vulgare) and its wild progenitor Hordeum vulgare ssp. spontaneum (H. ssp. spont.) were screened for gramine content at the seedling stage. H. ssp. spont. generally had higher gramine concentration compared with cultivated spring barley. Thus gramine concentrations might be raised in modern barley through crossings with selected H. ssp. spont. accessions and repeated back-crossings (BC) of selected offspring to cultivated barley. In the present study, the barley cultivar Lina was used as the recurrent parent. Lina was exceptional among the two-rowed barleys in that it contained moderate levels of gramine, whereas most of the others were very low in gramine. Chromosome-doubled haploid lines (DHs) from the first generation (F₁) had a skewed distribution towards higher gramine concentrations and so had the first back-cross generation (BC₁F₁-DHs). A hairy plant surface, another character proposed to confer resistance to aphids, was also found among some of the plants in the breeding material. BC₁F₁-DHs with a high proportion of the Lina genome, as determined in an analysis of PCR-based molecular markers, in addition to high gramine concentrations and hairy plant bases in two cases were tested for resistance to the barley pest Rhopalosiphum padi. However, based on aphid performance and preference tests, there were no indications that either high gramine concentrations or hairiness conferred resistance to R. padi when compared with Lina and a variety very low in gramine (Golf). The pattern was the same when the F₁ generation was evaluated in aphid performance tests along with Lina, Golf, and the six H. ssp. spont. parents. Aphid weight was consistently low on only one of the six H. ssp. spont. parents. Since previous reports of a positive relationship between gramine concentrations and resistance to R. padi were based on studies in Chile and Japan, a Chilean R. padi population was compared with three Swedish populations, but the responses of all four populations were similar.     

A highly efficient methodology for the preparation of N-methoxycarbazoles and the total synthesis of 3,3'-[oxybis(methylene)]bis(9-methoxy-9H-carbazole)

A convenient and highly efficient method is described for the synthesis of N-methoxycarbazole derivatives, including those with sterically demanding, benzannulated, or strongly electron-donating or -withdrawing substituents. Various N-methoxycarbazole derivatives were directly prepared in good-to-moderate yields by the Pd₂(dba)₃CHCl₃/9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene-catalyzed reactions of the corresponding dibromobiphenyl compounds and methoxya-mine. Based on this methodology, the first total synthesis of 3,3′-[oxybis(methylene)]bis(9-methoxy-9H-carbazole), an antimicrobial dimeric carbazole alkaloid previously isolated from the stem bark of Murraya koenigii, was achieved in 18% yield over seven steps from 1,2-dibromobenzene.     

Use of 2,3-bis(phenylsulfonyl)-1,3-butadiene as a reagent for the synthesis of azapolycyclic ring systems

2,3-Bis(phenylsulfonyl)-1,3-butadiene undergoes ready Michael addition with various primary amines to ultimately produce dihydropyrrolidines by a mechanism involving a proton shift after the initial conjugate addition followed by a subsequent intramolecular cyclization. A related transformation occurs with soft carbanion nucleophiles such as malonate esters. N-Alkyl imines also react to produce tetrahydropyridines by a sequence of reactions involving the transient intermediacy of a 1,3-diphenylsulfonyl diene. When the malonate ester contains a tethered π -bond, an initially formed allene undergoes a subsequent intramolecular [2+2]-cycloaddition to give bicyclo[4.2.0]-adducts.     

新型固相萃取技术的发展及应用于生物碱的富集及分离

固相萃取(SPE)是一种广泛使用的包括分离、纯化和浓缩的样品预处理方法,SPE技术以其高安全性、高效性、高选择性、高可靠性、高自动化程度以及低耗性等特点被广泛地应用在药物分析、化工分析、食品分析和环境分析等领域。文章介绍了近年来新型固相萃取技术的发展以及应用于生物碱的富集及分离。     

The Constituents of Roots and Stems of Illigera luzonensis and Their Anti-Platelet Aggregation Effects

Phytochemical investigation of the roots and stems of Illigera luzonensis afforded two new aporphine alkaloids (1) and (2), one new bisdehydroaporphine alkaloid (3), and one new benzenoid (4), along with 28 known structures. The structures of new compounds were elucidated by spectral and MS analysis. Among the isolated compounds, (1) and (4–13) were subjected into the examination for their inhibitory effects on the aggregation of washed rabbit platelets.     

MECC-AD法测定黄连和黄柏中小檗碱、巴马汀和药根碱的含量

建立检测黄连、黄柏中生物碱(小檗碱、巴马汀、药根碱)含量的MECC-AD测定方法。在自组装仪器上,以0.3 mm(i.d.)碳圆盘微电极为工作电极,在1.150 V(Ag/AgCl)的检测电位下,以含有0.008 mol·L-1的胆酸钠(SC)溶液与3%甲醇溶液的0.2mol·L-1H3BO3-0.05 mol·L-1Na2B4O7·10H2O缓冲液(pH值=8.45)为运行液;当毛细管长度65 cm(i.d.25μm),分离电压10 kV,三种待测物在15 min内完全分离。本方法测定三种生物碱的线性范围分别为(0.37~32.6、0.98~41.7、0.25~25.9μg·mL-1);检出限分别为(0.15、0.36、0.08μg·mL-1)。结论:该方法已成功应用于黄连、黄柏等中药材中3种生物碱含量的测定。     

尼泊尔黄堇中总生物碱的串联质谱分析

采用电喷雾串联质谱(ESI-MS/MS)法对尼泊尔黄堇中总生物碱进行分析。由一级质谱中各成分的准分子离子峰获知其相对分子质量,再由二级质谱的裂解碎片推测其结构特征。结合纯品的串联质谱分析,直接鉴定出从尼泊尔黄堇总生物碱中已经分离得到的10种异喹啉生物碱成分:stylopine(1),tetrahydrothalifendine(2),tetrahydroberberrubine(3),scoulerine(4),sinactine(5),protopine(6),cryptopine(7),α-allo-cryptopine(8),9-methyl-decumbenine C(9)和6-acetonyl-5,6-dihydrosanguinarine(10);另外还初步推测出2种未从该植物中分离得到的异喹啉生物碱成分。     

卵叶娃儿藤生物碱对宫颈癌细胞株HeLa的体外作用

为了观察卵叶娃儿藤总生物碱[Tylophora ovata(Lindl.)Hook.ex Steud,alkaloids TOHa]体外抑制人宫颈癌细胞株HeLa增殖、诱导细胞凋亡的作用,将不同浓度的TOHa与HeLa细胞在体外培养,用MTT法观察TOHa对HeLa细胞的生长抑制作用,测定其在490nm的OD值;用细胞形态学、AnnexinV/PI双标记检测细胞凋亡。结果表明,TOHa能抑制HeLa细胞的增殖和活力,呈现作用时间和剂量的依赖关系。HeLa细胞经TOHa作用后,Annexin V /PI-表达升高,Giemsa染色后出现凋亡细胞的特征性改变。