毛细管区带电泳测定芦荟中的有效成分

 建立了毛细管区带电泳测定中药芦荟中的有效成分芦荟甙和芦荟大黄素的分析方法。采用24 mmol/L的磷酸盐(pH 10.85)作为缓冲溶液,在电压为15 kV和检测波长为254 nm的条件下进行分离实验,芦荟提取液中有效成分获得基线分离。定量分析表明,芦荟甙的质量浓度为0.029 g/L～1.00 g/L时,其峰面积与质量浓度呈线性关系(r=0.997);芦荟大黄素的质量浓度为5.4 mg/L～84 mg/L时,其峰面积与质量浓度呈线性关系(r=0.999)。此外,还讨论了缓冲溶液的pH值、有机改性剂对两种有效成分迁移行为的影响。     

芦荟大黄素的电化学研究

用单扫示波极谱法研究了芦荟大黄素的电化学行为。在５％Ｎａ２ＣＯ３＋５％ＮａＯＨ（９＋１）底液中，芦荟大黄素于－０．８４Ｖ（Ｐ１）和－０．９７Ｖ（Ｐ２）处产生两个示波极谱峰，利用Ｐ１可测定芦荟大黄素，线性范围为 ０．１１－２４ｍｇ／Ｌ和３．０－２８．６ｍｇ／Ｌ，检测限为０．０６ｍｇ／Ｌ。将该法应用于中药大黄中的芦荟大黄素的测定，结果满意。另外，讨论了芦荟大黄素清除由邻苯三酚自氧化产生的超氧自由基（Ｏ２）的作用。     

Folin-Ciocalteu比色法测定库拉索芦荟花中多酚

建立Folin-Ciocalteu比色法测定库拉索芦荟花中多酚含量的方法。利用多功能微孔板分光光度计对Folin-Ciocalteu法检测库拉索芦荟花多酚的显色反应条件进行优化，再用紫外可见分光光度计对其方法稳定性、重现性及准确性进行验证。结果表明，向库拉索芦荟花样品溶液中加入Folin-Ciocalteu试剂1.0 mL、50 g/L碳酸钠溶液2.0 mL，用水定容至10 mL，于40℃避光显色60 min，测定反应体系在765 nm处的吸光度，多酚质量浓度在6.3～62.6μg/mL范围内与吸光度具有良好的线性关系，线性相关系数为0.999 6。样品测定值的相对标准偏差为1.42%(n=6)，测定方法的平均回收率为95.52%。该方法适用于库拉索芦荟花中多酚含量的测定。     

高效液相法测定芦荟胶囊中的芦荟甙

 建立了高效液相法测定芦荟胶囊中芦荟甙含量的方法。实验采用ODS柱 ,以甲醇 水 (体积比为 5 0∶5 0 )溶液为流动相 ,用紫外检测器于 2 98nm处检测。结果表明 ,芦荟甙的进样量为 0 0 2 μg～ 1 5 μg时 ,进样量与峰面积呈良好的线性关系 (r =0 9999) ;样品的加标回收率为 99 0 %～ 10 1 9% ;方法的精密度好 ,相对标准偏差(RSD)为 1 37% (n =6 )。方法快速、简便、准确 ,所测结果稳定、重现性好 ,可作为胶囊类保健食品质量检验的一个定量方法。     

高速逆流色谱分离纯化芦荟中的活性物质

1　实验部分1.1　仪器与试剂　　GS10A高速逆流色谱仪、8823A紫外检测器、S1007泵、3057记录仪、进样器(北京市新技术应用研究所)。　　氯仿、甲醇、丙酮、环己烷和乙酸乙酯均为分析纯。1.2　色谱条件　　以溶剂系统的上相为固定相、下相为流动相。以9.99mL/min的流速将上相泵入,以2mL/min的流速将下相泵入。螺旋管转子转速800r/min。检测器量程0～100mA,紫外检测波长254nm;记录仪走纸速度6cm/h。图1　以氯仿 甲醇 丙酮 水(体积比为9∶8∶1∶8)为溶剂系统的芦荟样品色谱图1.芦荟大黄素甙;4.芦荟大黄素.1.3　样品及其处理　　称取开普芦…     

火焰原子吸收光谱法测定芦荟中微量铁、锌含量

用火焰原子吸收光谱法测定了芦荟中铁、锌两种微量元素含量。结果表明,芦荟中铁和锌千含量分别为638、244μg/g。火焰原子吸收光谱法测定样品中铁含量和锌含量的相对标准偏差分别为7．06％,3．63％,加标回收率在95％～102．5％范围内,检测限分别为0．011μg,／mL和0．002μg／mL。     

芦荟大黄素1.5阶微分阳极溶出伏安法测定及电化学性质研究

研究了芦荟大黄素在以 0 .1mol/LHAc (pH 2 .89)为支持电解质 ,玻碳电极为工作电极的吸附伏安行为 .结果表明芦荟大黄素存在一个准可逆的双电子转移过程 ,其峰电流Ip 和峰电位Ep 与溶液 pH值有关 .同时还建立了用 1.5阶微分阳极溶出伏安法测定含量的新方法 .在 - 0 .80V(vs.SCE)电位下富集 ,可得一灵敏的微分阳极溶出峰 ,峰电位Ep 为 - 0 .38V ,峰电流Ip 与芦荟大黄素的浓度在 2 .0× 10 - 7～ 8.0× 10 - 6 mol/L范围内成线性关系 ,最低检出限为 1.0× 10 - 7mol/L .该法用于含有芦荟大黄素体系的测定 ,具有简便、快速、准确等优点     

火焰原子吸收光谱法测定芦荟中锰、铁、铜、锌、镍、钴

１　　引　　　　言芦荟作为药用和保健品越来越引起人们的重视。近年来人们将它作为良好的防癌、抗癌药品而食用。芦荟的主要成分为淡黄色结晶性甙,为芦荟大黄素甙,水解产生ｄ－阿拉伯胶糖、芦荟大黄素等。它有良好的抑菌作用,对表皮癣菌、星形奴卡氏菌等皮肤真菌均有不同的抑制作用。主治烧烫伤、肝经实热等症。还能治疗糖尿病、痔疾、中耳炎、减肥等多种疾病。是人们理想的保健品和药品。芦荟中的金属元素的分析,作者未见文献报道。本文用原子吸收光度法测定了３种芦荟中锰、锌、铜、铁、镍、钴的含量,得到了满意的结果。２　　实验…     

芦荟大黄素在水和非水溶剂中的电化学性质

在HAc-NaAc水溶液或二甲亚砜(DMSO)非水溶剂中,芦荟大黄素于铂电极上均显示一个准可逆的双电子转移过程,与HAc-NaAc溶液相比,芦荟大黄素在DMSO溶剂中的峰电位明显负移,且波形改变很大;HAc-NaAc溶液中,峰电流Ipa与芦荟大黄素的浓度在1.0×10-5~6.0×10-4mol/L范围内成线性关系,检测限为1.0×10-6mol/L.溶剂对芦荟大黄素的电化学性能有甚大的影响.     

芦荟中多糖的光度测定新方法

利用正交试验考察了芦荟多糖与刚果红显色反应的最佳条件；研究了麦芽糖糊精等多糖、蔗糖等低聚糖和葡萄糖等单糖对显色反应的影响；建立了简便快速、常见糖类基本无干扰的测定芦荟多糖含量的吸光光度法。对芦荟鲜叶和芦荟制品中的多糖进行分析，加标回收率在92％～96％范围内，相对标准偏差≤5％。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.