7-羟基香豆素及6, 7-二羟基香豆素与 DNA的作用机理及构效关系研究

 目的: 研究7-羟基香豆素（umbelliferone, UMB）和6, 7-二羟基香豆素（aesculetin, AES）与小牛胸腺DNA的作用机制,探讨其构效关系。方法: 采用荧光光谱法研究UMB和AES与DNA的结合作用,并计算相关结合参数,利用紫外光谱、盐效应、I-猝灭、与单双链DNA作用、DNA热变性温度及黏度测定等方法确定UMB和AES与DNA的作用模式。结果: DNA对UMB和AES的荧光猝灭机制均为静态猝灭;UMB和AES与DNA的结合常数分别为2.13×104和5.27×102 L?mol-1,作用力主要是氢键和范德华力。结论: UMB和AES与DNA的作用方式均为沟槽作用。     

HPLC法同时测定消瘤藤中茵芋苷、7-羟基香豆素、7-羟基-8-甲氧基香豆素的含量

摘要：目的:建立测定广西特色瑶药消瘤藤药材中茵芋苷、7-羟基香豆素、7-羟基-8-甲氧基香豆素含量的高效液相色谱的方法。方法:运用反相高效液相色谱法,色谱柱为Agilent Eclipse XDB-C18（250 mm×4.6 mm, 5μm）,流动相为乙腈-0.2%磷酸溶液,梯度洗脱,流速为1.0 ml·min-1,检测波长为320 nm,柱温为25℃,进样量10μl,以外标法定量。结果:茵芋苷浓度在1.032～103.2μg·ml-1之间与峰面积线性关系良好（r=0.999 9）,平均回收率为99.78%（RSD=2.7%,n=6）;7-羟基香豆素浓度在1.022～102.200μg·ml-1之间与峰面积线性关系良好（r=0.999 9）,平均回收率为98.78%（RSD=3.8%,n=6）;7-羟基-8-甲氧基香豆素浓度在1.112～111.2μg·ml-1之间与峰面积线性关系良好（r=0.999 9）,平均回收率为97.56%（RSD=3.7%,n=6）。结论:该方法操作简便、结果准确、重复性好,提供了一种更好的控制消瘤藤药材质量的方法。     

4种香豆素类中药小分子对胃蛋白酶结构影响研究

摘要：目的:研究4种结构上呈规律性变化的香豆素类药物与胃蛋白酶相互作用过程中对胃蛋白酶结构的影响,探讨其与胃蛋白酶间相互作用的机制。方法:在胃酸生理条件（pH=2.2±0.2）下,分别将不同浓度的香豆素、4-羟基香豆素、7-羟基香豆素、7-羟基-4-甲基香豆素与胃蛋白酶配置成溶液,采用紫外光谱（UV）和荧光光谱（FS）两种实验手段,获得香豆素类药物与胃蛋白酶相互作用的光谱特征。结果:不同浓度的4种香豆素类药物对胃蛋白酶的紫外光谱227 nm和272 nm左右吸收峰产生了一定程度的影响;香豆素、4-羟基香豆素、7-羟基-4-甲基香豆素在部分浓度下对胃蛋白酶的荧光产生增强作用,香豆素、4-羟基香豆素、7-羟基香豆素在部分浓度下对胃蛋白酶的荧光产生猝灭作用;4种香豆素类药物的紫外光谱与胃蛋白酶的荧光发射光谱均产生部分重叠。结论:4种香豆素类药物与胃蛋白酶之间存在不同程度的相互作用,对胃蛋白酶的二级结构及微环境均产生了不同程度的影响,且均存在非辐射能量转移;胃蛋白酶和4种香豆素类药物自身分子结构的性质导致两者之间的相互作用存在不规律性,作用机制可能比较复杂。     

2,3,4-三羟基苯甲醛缩4-氨基水杨酸希夫碱的合成表征和性质研究

目的以2,3,4-三羟基苯甲醛和4-氨基水杨酸为前体,合成2,3,4-三羟基苯甲醛缩4-氨基水杨酸希夫碱。方法采用回流方法得到产物,对产物进行紫外、红外和核磁的表征和使用荧光光谱进行性质研究。结果通过荧光光谱法研究HL与牛血清蛋白(BSA)之间存在的相互作用,研究它的猝灭机制,以及HL与BSA在不同温度下相互作用的结合常数Ka,结合位点数n以及热力学参数,以及HL与BSA之间作用的主要作用力。结论 HL与BSA的猝灭机制为静态猝灭,结合位点为1,范德华力和氢键是HL与BSA之间作用的主要作用力。     

HPLC测定参附强心丸中东莨菪内酯和7-羟基香豆素含量

目的:建立HPLC法测定参附强心丸中东莨菪内酯和7-羟基香豆素含量的方法.方法:采用二极管阵列检测器,色谱柱为Phenomenex Luna C18(250mm×4.6mm,5μm);流动相为甲醇-0.5％冰乙酸水溶液,梯度洗脱;流速为1.0mL/min;检测波长为345nm.结果:东莨菪内酯线性范围为0.0760～0.3800μg(R2=0.999),平均回收率为104.54％,RSD为2.27％,重复性RSD为1.22％(n=6),精密度RSD为0.90％(n=6),稳定性RSD为0.91％;7-羟基香豆素线性范围为0.0300～0.1500μg(R2=0.999),平均回收率为102.51％,RSD为1.04％,重复性RSD为5.08％(n=6),精密度RSD为0.91％(n=6),稳定性RSD为0.91％.结论:本研究所建方法稳定、可靠,可作为该制剂的质量控制方法.     

包载荧光探针香豆素-6的PLGA纳米粒的制备

目的以生物可降解材料聚乳酸,羟基乙酸共聚物（PLGA）为材料,制备包载荧光探针香豆素-6纳米粒,并进行处方优化。方法采用乳化-溶剂挥发法制备香豆素-6。PLGA纳米粒,以利用率和包封率为考察指标,正交试验对处方进行优化。结果制得香豆素-6纳米粒的包封率为51．6％,利用率为81．9％,平均粒径135nm,香豆素-6体外72h泄漏率低于2％。结论香豆素-6 PLGA纳米粒制备工艺简便可行,香豆素-6可作为荧光探针,用于纳米粒的动物体内示踪及靶向性研究。     

光谱法研究核苷类逆转录酶抑制剂药物与DNA的相互作用

目的 研究核苷类逆转录酶抑制剂药物(阿德福韦、拉米夫定、恩去他滨)与小牛胸腺DNA(ct-DNA)的相互作用及其作用机制.方法 采用荧光光谱法和热力学理论进行研究.结果 确定核苷类逆转录酶抑制剂药物与ct-DNA间的猝灭过程是静态猝灭;求得27°C时,药物与ct-DNA间的结合常数(K)分别为3.41×103、2.63×103、1.02×103 L·mol-1,结合位点数n分别为1.05、0.958、1.03,猝灭速率常数(Kq)分别为2.07×1011、3.50×1010、7.80×1010 L·mol-1·s-1.结论 核苷类逆转录酶抑制剂药物与小牛胸腺DNA间的主要作用为嵌插作用,与DNA结合的作用机制相似.     

依托泊苷与鲱鱼精DNA相互作用的研究

目的 研究依托泊苷与DNA的相互作用.方法 采用荧光光谱及紫外光谱法,结合Ⅰˉ效应、离子强度的影响及DNA熔点测定,分析依托泊苷与DNA光谱效应.结果 DNA对依托泊苷的内源荧光有明显的猝灭作用,猝灭过程为静态猝灭;结合常数KA=2.02×10 -4L·mol-1,结合位点数n=0.89.结论 依托泊苷与DNA的结合作用方式可能为沟槽作用.     

薄层荧光扫描法测定大力王糖浆中7—甲氧基香豆素

用乙醚振摇提取、乙醇定容后,在硅胶G CMC薄层板上用甲苯-醋酸乙酯-甲酸(5:1:0.1)为展开剂,分离大力王糖浆中的7-甲氧基香豆素,用岛津CS-910薄层扫描仪在激发波长325nm,发射波长400nm 处,荧光反射法线性扫描对7-甲氧基香豆素进行了含量测定.回收率平均值为103.11%,Cv 为2.77%,本方法简便、快速,重现性好。     

枸橼果实的香豆素和黄酮类成分研究

目的研究枸橼果实的化学成分。方法用硅胶柱色谱法及Sephadex LH-20柱色谱法进行分离纯化,依据理化性质和光谱数据鉴定化合物结构。结果从枸橼果实的95%乙醇提取物中分离鉴定了11个化合物,包括7个香豆素类化合物:7-羟基香豆素(1)、5,7-二羟基香豆素(2)、7-羟基-6-甲氧基香豆素(3)、5,7-二甲氧基香豆素(4)、6,7-二甲氧基香豆素(5)、佛手柑内酯(6)和8-(2',3'-二羟基-3'-甲丁基)-5,7-二甲氧基香豆素(7);4个黄酮类化合物:香叶木素(8)、柚皮素(9)、柚皮苷(10)和橙皮素(11)。结论化合物1,2,5～9为首次从枸橼中分离得到。     

Novel analogs of the sigma receptor ligand BD1008 attenuate cocaine-induced toxicity in mice

Previous studies have shown that BD1008 (N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1-pyrrolidinyl)ethylamine) and related analogs attenuate the toxicity and stimulant effects of cocaine through antagonism of sigma receptors. In the present study, six analogs of BD1008 (UMB 98-103) were synthesized and evaluated in receptor binding and behavioral studies. Competition binding studies confirmed that all six compounds have high affinity for sigma1 receptors, moderate affinity for sigma2 receptors, and low to negligible affinity for monoamine transporters, opioid, N-methyl-D-aspartate, dopamine, and 5-HT receptors. In behavioral pharmacological studies, pretreatment of mice with UMB 100, UMB 101, or UMB 103 significantly attenuated cocaine-induced convulsions and lethality. Together with earlier studies, the data suggest that analogs of BD1008 are promising medication development leads for reducing the toxicity of cocaine.     

Antigenotoxic activities of the natural dietary coumarins umbelliferone,herniarin and 7-isopentenyloxy coumarin on human lymphocytes exposed to oxidative stress

Abstract

The antigenotoxic effects of umbelliferone (UMB), herniarin (HER) and 7-isopentenyloxy coumarin (7-IP), common natural dietary coumarins, were evaluated on the human lymphocyte DNA damage using single-cell gel electrophoresis. H₂O₂-induced DNA break was measured based on the percentage of DNA in tail, and the antigenotoxic effects of the tested compounds were compared with that of ascorbic acid (10, 25, 50, 100 and 200?μM). UMB, HER and 7-IP did not show any genotoxicity, as compared to phosphate-buffered saline. Treatment with UMB, HER and 7-IP led to a significant reduction in the percentage of DNA in tail induced by H₂O₂ (p?<?0.001) at all concentrations. The presence of prenyl moiety in the chemical structure of 7-IP may contribute to its better antigenotoxic property, compared to UMB. The results of this study showed that 7-IP possessed the best antigenotoxic activity among the tested compounds.     

Effects of UMB24 and (+/-)-SM 21, putative sigma2-preferring antagonists, on behavioral toxic and stimulant effects of cocaine in mice

Earlier studies have demonstrated that antagonism of sigma1 receptors attenuates the convulsive, lethal, locomotor stimulatory and rewarding actions of cocaine in mice. In contrast, the contribution of sigma2 receptors is unclear because experimental tools to selectively target this subtype are unavailable. To begin addressing this need, we characterized UMB24 (1-(2-phenethyl)-4-(2-pyridyl)-piperazine) and (+/-)-SM 21 (3alpha-tropanyl-2-(4-chorophenoxy)butyrate) in receptor binding and behavioral studies. Receptor binding studies confirmed that UMB24 and (+/-)-SM 21 display preferential affinity for sigma2 over sigma1 receptors. In behavioral studies, pretreatment of Swiss Webster mice with UMB24 or (+/-)-SM 21 significantly attenuated cocaine-induced convulsions and locomotor activity, but not lethality. When administered alone, (+/-)-SM 21 produced no significant effects compared to control injections of saline, but UMB24 had locomotor depressant actions. Together, the data suggest that sigma2 receptor antagonists have the potential to attenuate some of the behavioral effects of cocaine, and further development of more selective, high affinity ligands are warranted.     

Comparison of the effect of 4-hydroxycoumarin and umbelliferone on the phase transition of dipalmitoylphosphatidylcholine (DPPC) bilayers

The study compares the effect of the addition of two coumarins: 4-hydroxycoumarin (4-HC) and 7-hydroxycoumarin (umbelliferone; UMB) on dipalmitoylphosphatidylcholine (DPPC) membranes. The study was based on microcalorimetric and fluorescence measurements. The examinations have shown that 4-HC changes parameters of phase transition of DPPC membranes to a greater degree than UMB. It is associated with different location of each coumarin in the lipid membrane, which is caused by different orientation of polarity of coumarin molecules. 4-HC molecules that are amphiphilic "along" incorporate inside the membrane interacting with lipid carbohydrate chains. UMB molecules amphiphilic "across" the molecule are not incorporated inside the membrane and do not interact with acyl chains.     

Novel sigma (sigma) receptor agonists produce antidepressant-like effects in mice.

Many antidepressant drugs interact with sigma receptors and accumulating evidence suggests that these proteins mediate antidepressant-like effects in animals and humans. sigma Receptors are localized in brain regions affected in depression, further strengthening the hypothesis that they represent logical drug development targets. In this study, two novel sigma receptor agonists (UMB23, UMB82) were evaluated for antidepressant-like activity in mice. First, radioligand binding studies confirmed that the novel compounds had preferential affinity for sigma receptors. Second, the forced swim test, a well established animal model for screening potential antidepressant drugs, showed that both compounds dose-dependently reduced immobility time. The sigma receptor antagonist BD1047 attenuated the antidepressant-like effects of UMB23 and UMB82. Third, locomotor activity suggested that the effects of UMB23 and UMB82 in the forced swim test were not due to non-specific motor activating effects. Together, the data provide further evidence that sigma receptor agonists represent a possible new class of antidepressant medication.     

Umbelliferone modulates depression-like symptoms by altering monoamines in a rat post-traumatic stress disorder model

Post-traumatic stress disorder (PTSD) is a debilitating psychological disease that is triggered by traumatic events. It is known to cause various complications, including anxiety and depression. Umbelliferone (UMB) is a natural product of the coumarin family. This substance has been reported to exert antioxidant, anti-inflammatory, neuroprotective, and other biological effects. We used the open field test (OFT) and the forced swimming test (FST) to examine the effects of UMB on depression-like symptoms in rats after exposure to a single prolonged stress (SPS), which led to dysregulated activation of the serotonergic system. Male rats were given UMB (20, 40, or 60 mg/kg, intraperitoneal injection) once daily for 14 days after exposure to an SPS. Daily UMB administration significantly improved depression-like behaviors on the FST, increased the number of lines crossed in the central zone of the OFT, and reduced freezing behavior in both contextual and cued fear conditioning. UMB treatment attenuated the SPS-induced decrease in serotonin (5-HT) concentrations in the hippocampus and amygdala. The increased 5-HT concentration during UMB treatment was partially due to a decrease in the ratio of 5-hydroxyindoleacetic acid/5-HT in the hippocampus of rats with PTSD. According to our results, UMB has an antidepressant effect in rats exposed to an SPS, suggesting that this natural product of the coumarin family can be used to effectively treat PTSD.     

Influence of umbelliferone on membrane-bound ATPases in streptozotocin-induced diabetic rats

The activities of membrane-bound ATPases are altered both in erythrocytes and tissues of streptozotocin (STZ)-induced diabetic rats and diabetic patients. Umbelliferone (UMB), a natural antioxidant, is a benzopyrone occurring in nature, and it is present in the fruits of golden apple (Aegle marmelos Correa) and bitter orange (Citrus aurantium). Earlier we evaluated and reported the effect of UMB on plasma insulin and glucose, and this study was designed to evaluate the effect of umbelliferone on membrane-bound ATPases in erythrocytes and tissues (liver, kidney and heart) of STZ-induced diabetic rats. Adult male albino rats of Wistar strain, weighing 180-200 g, were made diabetic by an intraperitonial administration of STZ (40 mg/kg). Normal and diabetic rats were treated with UMB dissolved in 10% dimethyl sulfoxide (DMSO) and diabetic rats were also treated with glibenclamide as drug control, for 45 days. In our study, diabetic rats had increased level of blood glucose and lipid peroxidation markers, and decreased level of plasma insulin and decreased activities of total ATPases, (Na(+)+K(+))-ATPase, low affinity Ca(2+)-ATPase and Mg(2+)-ATPase in erythrocytes and tissues. Restoration of plasma insulin and glucose by UMB and glibenclamide seemed to have reversed insulin, glucose and lipid peroxidation markers, and diabetes-induced alterations in the activities of membrane-bound ATPases. Thus, our results show that the normalization of membrane-bound ATPases in various tissues, is due to improved glycemic control and antioxidant activity by UMB.     

巴罗沙星与DNA的相互作用及Mg2+的影响

目的研究巴罗沙星与DNA的分子作用机制和Mg²⁺对巴罗沙星与DNA相互作用的影响。方法利用荧光光谱研究巴罗沙星与DNA的作用强度并计算热力学数据ΔH；利用紫外光谱、黏度测定、竞争实验、与变性DNA作用的比较等方法确定巴罗沙星与小牛胸腺DNA的相互作用方式；利用荧光光谱考察Mg²⁺对巴罗沙星与小牛胸腺DNA相互作用的影响。结果DNA对巴罗沙星的荧光猝灭常数为(5.43±0.07)×10³ L·mol^-1，ΔH=-8.03 kJ·mol^-1；Mg²⁺使巴罗沙星与DNA的作用增强。结论巴罗沙星以沟槽键合方式与DNA相互作用；Mg²⁺对巴罗沙星与DNA的结合有中介作用。     

盐酸西布曲明与牛血清白蛋白结合作用的光谱学研究

目的运用光谱学方法研究在生理pH值条件下盐酸西布曲明与牛血清白蛋白之间的结合作用。方法 通过荧光法和吸收光谱法确定了盐酸西布曲明对牛血清白蛋白的荧光猝灭机制。依据Scatchard方程测定了不同温度下该结合反应的结合常数和结合位点数。根据热力学方程讨论了两者间的主要作用力类型。结合同步荧光分析了盐酸西布曲明对牛血清白蛋白构象的影响。结果盐酸西布曲明对牛血清白蛋白的荧光猝灭机制为静态猝灭。在8，25和37 ℃时盐酸西布曲明与牛血清白蛋白的结合常数分别为1.21×10⁵，8.31×10⁴和6.97×10⁴ L·mol^-1，结合位点数均为1。结合反应的热力学参数为ΔH=-9.70 kJ·mol^-1，ΔS=56.41 J·mol^-1·K^-1。结论 两者结合的主要作用力类型是静电作用。盐酸西布曲明在体内能够被血清蛋白存储和转运且结合时对蛋白构象无影响。