3种分光光度法对天然抗氧化物质抗自由基性能的分析检测

用1,1 二苯基 2 苦基肼(DPPH)自由基捕获、亚硝基R盐 Co3 褪色、连苯三酚红等3种分光光度法对3种野生植物抗氧化剂的对自由基的作用进行了分析检测及方法比较研究。3种分光光度法对自由基的分析检测及抗氧化剂的抗自由基性能检测方法,对于普通实验室检测自由基或相关的研究工作具有很好的实用性。没食子酸丙酯及葡萄籽提取物的抗氧化性要优于灯盏花素提取物。对自由基的清除率可以达到40%～80%,具有很好的抗氧化能力及氧自由基清除作用。     

抗氧化剂的毛细管电泳-间接化学发光联用在线评价方法研究

根据碱性条件下羟自由基与luminol反应会产生化学发光而抗氧化剂能够清除羟自由基从而抑制发光的原理, 结合毛细管电泳技术, 建立了一种针对多组分共存体系中抗氧化组分的在线评价的新方法. 对这种毛细管电泳-间接化学发光检测技术, 优化化学发光的各种条件, 考察了抗氧化剂硫脲和麻黄碱的抗氧化活性, 采用曲线拟合求出它们对羟自由基的半数清除浓度(IC₅₀), 得出抗氧化活性大小为麻黄碱＞硫脲, 这与荧光分光光度法的结果一致. 该方法初步应用于评价中药槐米提取物化学组分的抗氧化活性.     

罗丹明B-Mn2+-H2O2体系同步荧光分光光度法测定中药的抗氧化活性

罗丹明B能产生特征荧光,其激发波长和发射波长分别为554 nm和575 nm。弱碱性介质中Mn2 -H2O2体系产生的羟自由基可迅速氧化罗丹明B使荧光猝灭,而中药水提取物可部分清除溶液中羟自由基,从而使其荧光猝灭程度减弱。用Δλ=21 nm的同步荧光分光光度法建立了测定中药抗氧化活性的方法。测试了11种中药的抗氧化活性,以五倍子的抗氧化活性最强。     

甲壳素富集固相反射分光光度法测定矿样中的铁

本文研究了一种新的固相分光光度法－固相反射分光光度法。论文从理论上推导出反射吸附值ＡＲ与物质相应的浓度Ｃ的定量关系。并以甲壳素为吸附剂，以铁，邻二氮菲和十二烷基磺酸钠的缔合物为被吸附物，进行了甲壳素相的反射分光光度法研究。     

阴离子合成洗涤剂检测方法的比较和探讨

对5－Br－PADAP钴法和二氮杂菲萃取分光光度法测定水中基苯磺酸盐（ABS）分别进行了空白测定、精密度、准确度、标准物质测定等对比试验。结果表明，两者无显著性差异，但二氮杂菲法更方便，检测成本低，线性范围较广，更适合生活饮用水及不源水中ABS的测定。     

褪色光度法测定Fenton反应产生的羟自由基及其应用

建立检测Fenton反应产生羟自由基的新方法。Fenton反应产生的羟自由基与苋菜红反应，颜色发生变化，用分光光度计测定其△A510值的变化，可间接测定羟自由基的生成量。通过对测定条件的研究，确定了体系最佳实验条件。抗氧化药物甘露醇、硫脲与羟自由基清除率具有明显的量效关系。测定了阿魏酸、芦丁等几种中药活性成分清除羟自由基的功能，此法可用于羟自由基清除剂的筛选及抗羟自由基机理研究。     

鸡足山耳蕨总黄酮的提取及抗氧化性研究

研究鸡足山耳蕨中总黄酮的提取及其抗氧化性.采用70％乙醇提取鸡足山耳蕨中总黄酮,用NaNO2Al(NO3)3-NaOH分光光度法测定黄酮含量,将提取液采用Fenton体系、普鲁士蓝法进行体外抗氧化活性研究,用硫代巴比妥酸(TBA)分光光度法研究其对羟自由基·OH引发DNA氧化损伤的抑制作用.结果表明样品中总黄酮含量为4.98％,回收率99.78％( RSD=1.06％,n=5).总黄酮浓度为90μg/mL时,对·OH的清除率可达36.2％;浓度为87.5μg/mL时,对羟自由基引发DNA损伤的抑制率可达93.0％.说明鸡足山蕨中总黄酮对羟自由基有较好的清除能力,对DNA氧化损伤有显著抑制作用.     

红景天苷衍生物的合成及其抗氧化活性

以酪醇为原料，通过K-K法合成了3个红景天苷衍生物：苄基酪醇-β-D葡萄糖苷、苄基酪醇-β-D半乳糖苷及苄基酪醇-β-D七乙酰麦芽糖苷，其结构经¹H NMR和¹³C NMR表征。采用还原力法及DPPH自由基清除法，考查了化合物的体外抗氧化活性。结果表明：不同浓度的红景天苷及其衍生物均具有还原能力及清除DPPH自由基的活性，且活性强弱与浓度成正比。     

黄酮的研究现状

黄酮是存在于自然界中的一大类物质。黄酮的提取方法主要有微波、超声波、酶解、浸提和超临界萃取等。一般采用硅胶过柱分离、颜色法进行定性检测,HPLC和紫外分光光度法进行定量检测。黄酮活性的测定主要是测其抗氧化性能。     

水中六价铬分析方法研究进展

对近年来水中六价铬的检测方法进行了综述,包括分光光度法、原子吸收分光光度法、离子色谱及其联用法、液相色谱及其联用法。对几种检测方法进行分析,展望了六价铬测定方法的发展方向。     

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.