乙酰阿魏酸丹皮酚酯的合成和体外抗氧化活性研究

目的:乙酰阿魏酸丹皮酚酯(A-Fe-Pae)的体外抗氧化活性研究。方法:采用邻二氮菲-Fe~(2+)氧化法及DPPH法测定阿魏酸、丹皮酚、抗坏血酸(VC)以及乙酰阿魏酸丹皮酚酯在体外对·OH和DPPH·的清除能力,计算表观清除率(CL)。结果:前药清除·OH、DPPH·的能力要小于Vc、阿魏酸和丹皮酚。结论:拼合后的酯类前药活性略低于原料药。     

丹皮总黄酮的提取及抗氧化活性研究

以丹皮为原料提取丹皮总黄酮,并测得其在丹皮中的含量为1.6304%。以常用的化学合成抗氧化剂2,6-二叔丁基-4-甲基苯酚(BHT)和叔丁基对苯二酚(TBHQ)为对照,通过4种方法评价了丹皮总黄酮的抗氧化活性。结果表明,在相同浓度条件下,丹皮总黄酮对羟基自由基(·OH)清除率对DPPH自由基(·DPPH)清除率对超氧阴离子自由基(·O-2)清除率对小鼠肝组织脂质过氧化的抑制率;丹皮总黄酮具有较强的抗氧化能力,其抗氧化活性略低于或等于TBHQ的抗氧化活性,远远大于BHT的抗氧化活性,在较低浓度下即具有对多种氧化反应的抑制作用。表明,丹皮总黄酮是一种很有发展前景的天然抗氧化剂。     

安康油用牡丹不同部位主要成分含量测定与比较

采用超声法提取油用牡丹地上部分的丹皮酚和没食子酸,通过高效液相色谱法测定并比较了不同部位的丹皮酚和没食子酸含量。结果表明,油用牡丹地上部分的丹皮酚含量大小依次为籽粕叶籽壳细枝粗枝,含量最高的部位是籽粕,达3 516.36μg·g~(-1);没食子酸含量大小依次为叶细枝粗枝籽壳籽粕,含量最高的部位是叶,可达1 548.48μg·g~(-1)。油用牡丹地上部分丹皮酚和没食子酸含量较高,具有开发利用价值。     

杜仲叶不同溶剂萃取物对ACE酶活的抑制作用

探讨了杜仲叶不同溶剂萃取物对血管紧张素转化酶(ACE)的抑制作用及抗氧化能力。采用系统溶剂萃取法分离杜仲叶有效成分,分别评价了不同溶剂组分对DPPH·、羟基的清除效果及对ACE的抑制能力。不同溶剂萃取物活性成分含量存在显著性差异(P<0.05)。抗氧化研究表明,正丁醇提取物对DPPH·清除作用最强,清除率为76.55%;二氯甲烷提取物对羟基清除作用最强,清除率为48.9%;乙酸乙酯提取物对ACE活性抑制率最高为30%。ACE抑制率与DPPH·、羟基清除率及黄酮、多酚、绿原酸、京尼平苷酸含量之间存在正相关性。在研究抗氧化及ACE酶抑制剂时正丁醇萃取物、二氯甲烷萃取物、乙酸乙酯萃取物应被作为重点考察对象,黄酮、多酚、绿原酸、京尼平苷酸可能是抑制ACE的物质基础。     

黔产朱砂莲多酚含量及其抗氧化活性研究

目的:为了研究黔产朱砂莲中总多酚和总黄酮的含量及其抗氧化活性。方法:采用福林酚比色法和亚硝酸铝比色法分别测定总多酚和总黄酮含量,同时采用DPPH自由基清除能力和总抗氧化能力评价香蓼总多酚的抗氧化能力。结果:朱砂莲总多酚和总黄酮的含量均较高,其值分别为(87.47±0.21)mg·g~(-1)和(245.00±0.50)mg·g~(-1);朱砂莲总多酚还原能力和DPPH自由基清除率高于TBHQ,但朱砂莲总黄酮还原能力和DPPH自由基清除率小于TBHQ;朱砂莲总多酚和总黄酮清除DPPH自由基的IC_(50)值0.004 g·L~(-1)和0.24 g·L~(-1)。结论:朱砂莲多酚类物质具有很强的自由基清除能力和抗氧化能力,是天然的自由基清除剂和抗氧化活性剂。     

酚类化合物体外自由基清除能力的研究

本文研究了多种酚类化合物(没食子酸、3,4-二羟基苯甲醛、3,4-二羟基苯甲酸、白藜芦醇、羟基酪醇、4-羟基-3-甲氧基苯甲醇、香草醛)对DPPH、ABTS自由基的清除能力,并以BHT作为参照对象进行自由基清除能力的综合评价。实验结果表明,3,4-二羟基苯甲醛、没食子酸、3,4-二羟基苯甲酸和羟基酪醇对DPPH的清除能力比BHT强;而在ABTS的清除能力上,除了香草醛外的酚类化合物均有强于BHT的自由基清除能力。研究表明,酚类化合物的浓度、酚羟基含量、酚羟基位置、分子结构,如苯环上的其他基团对酚类化合物清除自由基的能力均有影响。     

多乙烯多胺桥联受阻酚类抗氧剂的合成及其清除DPPH·性能

以二乙烯三胺和三乙烯四胺为桥联基,β-(3,5-二叔丁基-4-羟基苯基)丙酰氯为抗氧化功能基团,通过酰胺化缩合反应合成了两类具有不同对位桥联基团的受阻酚类抗氧剂。采用傅里叶红外光谱和核磁共振氢谱证实了合成的多乙烯多胺桥联受阻酚类抗氧剂的化学结构。DPPH法研究了多乙烯多胺桥联受阻酚类抗氧剂清除自由基的性能,并探索了酚羟基个数和对位桥联基结构对受阻酚类抗氧剂清除自由基性能的影响。结果表明,多乙烯多胺桥联受阻酚类抗氧剂具有良好的清除DPPH·能力,且随着抗氧剂分子中酚羟基个数的增加,清除DPPH·的活性增加,分子中含有4个酚羟基的三乙烯四胺受阻酚类抗氧剂的抗氧化效率（AE）达到2.65×10^-2 L/(mol·s)。对位桥联基结构对受阻酚类抗氧剂清除DPPH·能力有较大影响,季戊四醇为桥联基的受阻酚类抗氧剂1010清除DPPH·能力最强,其抗氧化效率（AE）为3.08×10^-2L/(mol·s);乙二胺为核的1.0代树枝状受阻酚类抗氧剂清除DPPH·能力最弱,其抗氧化效率（AE）为2.60×10^-2 L/(mol·s)。     

双黄连口服液中多种有效成分测定

目的:建立HPLC法同时测定双黄连口服液中绿原酸、栀子苷、丹皮酚和黄芩苷的含量。方法:采用安捷伦C18的色谱柱(4.6mm×150mm,5μm),流动相采用乙腈-0.6%磷酸的水溶液,梯度洗脱的流速为1.0m L·min~(-1),色谱柱温为30℃,检测波长分别为238nm(栀子苷),274nm(丹皮酚),280nm(黄芩苷),327nm(绿原酸)。结果:绿原酸、栀子苷、黄芩苷、丹皮酚进样量分别在0.005~0.173μg(r=0.9998)、0.026~1.231μg(r=0.9995)、0.041~1.682μg(r=0.9997)、0.006~0.249μg(r=0.9994)与峰面积呈良好的线性关系,平均回收率(n=6)分别为98.24%、99.10%、98.46%、98.65%,精密度RSD均小于1.0%,重复性RSD均小于1.0%,供试品溶液放置24h内稳定。含量测定的结果表明了不同生产企业之间各成分的含量不尽相同,部分生产企业不同生产批次之间也有较大的差异。结论:本法适用于同时测定双黄连口服液中绿原酸、栀子苷、黄芩苷和丹皮酚的含量。     

二葡糖基没食子酸的合成及其性能研究

以没食子酸甲酯和五乙酰基葡萄糖为原料,经过乙酰化反应、成盐、酸化等过程合成了美白剂二葡糖基没食子酸,并通过IR,MS,¹H NMR和¹³C NMR确认了最终产物的结构。同时考察了美白剂二葡糖基没食子酸对酪氨酸酶活性的影响、酪氨酸二酚酶的抑制作用机制以及抗氧化能力。研究表明:以L-酪氨酸为底物时,二葡糖基没食子酸对酪氨酸单酚酶的半抑制浓度IC₅₀为1.46 mg/mL,以L-多巴为底物时,二葡糖基没食子酸对酪氨酸二酚酶的半抑制浓度IC₅₀为2.68 mg/mL,而且从Lineweaver-Burk图获得的抑制机理表明二葡糖基没食子酸对酪氨酸二酚酶的抑制作用表现为竞争性抑制,抑制常数K_m为2.43 mg/mL。没食子酸相比于同质量浓度下的V_max对DPPH自由基的清除效果更好,而二葡糖基没食子酸相比于同质量浓度下的V_c,其对DPPH自由基仍存在一定的清除作用。     

红葡萄酒、桃红葡萄酒和白葡萄酒的抗氧化活性比较

本文比较了红葡萄酒、桃红葡萄酒和白葡萄酒的总酚含量及抗氧化活性差异。通过比较红葡萄酒、桃红葡萄酒和白葡萄酒的总酚含量、1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力、Fe~(3+)总抗氧化能力(FRAP)、铁还原能力、清除羟基自由基能力等试验,评价不同种类葡萄酒的抗氧化活性。实验结果表明,红葡萄酒总酚含量最高,达到GAE 2120mg·L~(-1)。其中红葡萄酒的DPPH自由基清除试验、铁还原能力试验、清除羟基自由基能力试验的半数抑制浓度(IC_(50))值所对应的葡萄酒稀释倍数分别为:0.046、0.033和0.13,Fe~(3+)总抗氧化能力(FRAP)试验结果为449.57μmol·L~(-1) Fe SO_4。红葡萄酒、桃红葡萄酒和白葡萄酒均具有一定的抗氧化活性,活性强弱依次为红葡萄酒桃红葡萄酒白葡萄酒。     

Preparation ofcis,cis,cis-5,8,11-eicosatrienoic acid from arachidonic acid

Arachidonic acid was reduced by hydrazine to yield isomeric eicosatrienoic acids with other products. Methylcis,cis,cis-5,8,11-eicosatrienoate was isolated from the products by silver ion chromatography and preparative gas liquid chromatography in 8% yield. The structure was confirmed by spectral studies and oxidative degradation.     

Polyesters based on hydroxybenzoic acid,hydroquinone, sebacic acid,and suberic acid Molecular design towards broad nematic range

Abstract

To achieve a thermotropic liquid crystalline polymer with a relatively low melting temperature and a broad mesophase range, a series of polyesters based on hydroxybenzoic acid (HBA), hydroquinone (HQ), sebacic acid (SEA), and suberic acid (SUA) have been designed and synthesised. The molecular design was based on two concepts. First, the flexible segment of SUA is shorter than that of SEA. Replacement of SEA with SUA units would lead to an increase in the chain rigidity and hence the nematic to isotropic transition temperature. Second, since SEA and SUA have similar reactivity, the partial replacement of SEA with SUA units would randomise the structure and thus cause depression of melting points. DSC shows that the melting temperatures of some HBA/HQ/SEA/SUA polymers are indeed lower than the corresponding HBA/HQ/SEA polymer. Liquid crystallinity of the polymers was examined using polarised light microscopy. This verified that the clearing point of the HBA/HQ/SEA/SUA polymers increases as the SUA concentration increases. At a HBA/HQ/SEA/SUA molar ratio of 60:40:20:20, the crystallites melt completely at ~200°C, while the clearing point is still well above 300°C. This liquid crystalline polyester has great potential to act as a processing aid for conventional thermoplastics with moderate processing temperature windows.     

Metabolism of14C-labelled oleic acid,erucic acid and nervonic acid in rats

1-¹⁴C-Oleic acid, 2-¹⁴C-erucic acid and 2-¹⁴C-nervonic acid were administered to rats by tail-vein and the distribution of radioactivity in liver lipids was determined at intervals from 15 min to 6 hr after injection. High levels of activity were found after short time intervals which were mainly associated with triglycerides in the case of oleic acid and with free fatty acids in the case of erucic acid and nervonic acid. The activity in these lipids decreased with time and was later exceeded by that in more polar lipids. In rats given erucic acid or nervonic acid, sphingolipids were more highly labelled than glycerophosphatides. Nervonic acid showed little tendency to form a complex with serum albumin and erucic acid complexed less readily than palmitic acid. Presented at the AOCS Meeting in Houston, April 1965.     

次磷酸、亚磷酸、正磷酸联合生产新工艺

在作者开发的高速反应器一步法制专用级次磷酸钠的基础上进一步将生成的次磷酸钠和副产的亚磷酸氢钙用离子膜电渗析法制成纯度更高的次磷酸及亚磷酸产品,产品质量升级,回收利用了副产亚磷酸氢钙,并减少了原料烧碱的用量。该新工艺成本低,能耗小,无三废排出,产品多样化,属循环经济、环境友好新工艺。     

α,α''''-二氨基己二酸四亚甲基膦酸的合成

以α,α'-二溴代己二酸二乙酯为原料,经Gabriel、水解和Mannnich 3步反应,合成出α,α'-二氨基己二酸-N,N,N',N'-四亚甲基膦酸,产物的总收率30.6%.用 13CNMR、1HNMR、IR、MS和元素分析对合成产物及有关中间体--α,α'-二邻苯二甲酰亚胺基己二酸二乙酯、α,α'-二氨基己二酸进行了表征.     

Eskimo plasma constituents,dihomo-γ-linolenic acid,eicosapentaenoic acid and docosahexaenoic acid inhibit the release of atherogenic mitogens

Studies in man and laboratory animals suggest that ω3 polyunsaturated fatty acid consituents of fish oils have antiatherosclerotic properties. We have studied the effects of several such polyunsaturated fatty acids for ability to modify the in vitro release of mitogens from human platelets. Such mitogens may produce the fibroproliferative component of atherosclerotic plaques. Both 5,8,11,14,17-eicosapentaenoic acid (20∶5ω3) and 4,7,10,13,-16,19-docosahexaenoic acid (22∶6ω3), major constituents of fish oils, inhibited adenosine diphosphate-induced aggregation of platelets and the accompanying release of mitogens. These effects are dose dependent. Linolenic acid (18∶3ω3), the biosynthetic precursor of eicosapentaenoic acid, also inhibited platelet aggregation and mitogen release. Eicosapentaenoic acid also inhibited mitogen release from human monocyte-derived macrophages, which, in vivo, are an additional source of mitogens during atherogenesis. Potent inhibition of human platelet aggregation and mitogen release was also seen with dihomo-γ-linolenic acid (8,11,14-eicosatrienoic acid 20∶3ω6), whose levels are reportedly elevated in Eskimos subsisting on marine diets. We conclude that diets that elevate plasma and/or tissue levels of eicosapentaenoic acid, docosahexaenoic acid and dihomo-γ-linolenic acid precursor γ-linolenic acid (18∶3ω6) may exert antiatherosclerotic effects by inhibiting the release of mitogens from platelets and other cells.     

高效液相色谱法测定丁二酸、戊二酸和己二酸

建立了混合二元酸的反相离子对液相色谱法 ,使极性强、电离常数非常接近的丁二酸、戊二酸和己二酸得到完全分离。该方法与气相色谱法相比 ,样品不需预处理 ,分析速度快。绘制了标准工作曲线     

Simultaneous detection of ascorbic acid, uric acid and homovanillic acid at copper modified electrode

The copper was deposited on glassy carbon (GC) and indium tin oxide (ITO) electrodes by electrochemical method. The copper structures on electrode were characterized by atomic force microscope, X-ray diffractometeric pattern and differential pulse voltammetric studies. Optimal conditions for uniform growth of copper structures on the electrode were established. Voltammetric sensor was fabricated using the copper deposited GC electrode for the simultaneous detection and determination of uric acid (UA) and homovanillic acid (HVA) in the presence of excess concentrations of ascorbic acid (AA). The voltammetric signals due to AA and UA oxidation were well separated with a potential difference of 400 mV and AA did not interfere with the measurement of UA and HVA at the GC/Cu electrode. Linear calibration curves were obtained in the concentration range 1-40 μM for AA and 20-50 μM for UA at physiological pH and a detection limit of 10 nM of UA in the presence of 10-fold excess concentrations of AA was achieved. The simultaneous detection of submicromolar concentrations of AA, UA and HVA was achieved at the GC/Cu electrode. The practical utility of the present GC/Cu modified electrode was demonstrated by measuring the AA content in Vitamin C tablet, UA content in human urine and blood serum samples with satisfactory results.     

Preparation and characterizations of thermotropic copolyesters of p-hydroxybenzoic acid,sebacic acid,and hydroquinone

A series of copolyesters of p-hydroxybenzoic acid (HBA), sebacic acid and hydroquinone were prepared by melt polycondensation of p-acetoxybenzoic acid, sebacic acid and p-phenylene diacetate. The copolyesters were characterized by IR, NMR, DSC, polarized microscopy, and X-ray diffraction. It was found that the copolyesters exhibited liquid crystallinity when the HBA content was 25–67 mol %. The copolyesters with an HBA content of 25–43 mol % showed a nematic phase and a biphasic range, and the isotropization temperature increased as the HBA content increased. The copolyesters with an HBA content of 54–67 mol % showed a nematic phase up to above 400°C. The liquid crystalline order increased as the HBA content increased due to the increased of the average length of the rigid moieties. © 1995 John Wiley & Sons, Inc.     

Dimer acid structures: Cyclic structures of clay catalyzed dimers of normal linoleic acid, 9-cis, 12-cis-Octadecadienoic acid

The clay catalyzed dimer of linoleic acid has been examined by mass spectrometry of the unhydrogenated, the partially hydrogenated and completely hydrogenated dimer. The results show that monocyclic, bicyclic and tricyclic structures are present. Monocyclic structures predominate, bicyclic structures are also prominent, and tricyclic structures are relatively minor. The monocyclic structure is believed to arise from a Diels-Alder type addition reaction. The bicyclic structure may result from a free radical coupling followed by intramolecular ring closure. The monocyclic structure in the unhydrogenated dimer appears to be mostly a benzene ring with saturated and unsaturated side-chains. It probably is formed by hydrogen transfer from the Diels-Alder cyclohexene structure first formed. Little, if any, of the Diels-Alder dimer structure as such is present. The catalytic linoleate dimer has a higher ratio of monocyclic to bicyclic dimer than does the noncatalytic (thermal) dimer made from normal (nonconjugated) linoleate, while the thermal dimer of a conjugatedtrans-trans linoleate is exclusively monocyclic. It is suggested that the clay catalyzes conjugation and hence favors the Diels-Alder reaction, and then catalyzes hydrogen transfer to aromatize the cyclohexene ring.