【作者】 李勇；

【导师】 杨正银；

【作者基本信息】 兰州大学 ， 无机化学， 2012， 博士

【摘要】 黄酮类化合物因其独特的结构而在抗癌抗肿瘤以及清除自由基方面具有良好的应用前景,将它们与希夫碱及其金属配合物等相关方面结合起来从而可以制备生物活性更高的化合物。在本文中,我们合成并表征了一系列黄酮类希夫碱配体及其金属配合物,并研究了它们与DNA结合的性质及抗氧化性能。磁性纳米粒子在生物医学方面也有广泛的用途,如可以用于生物分离、离子探针、核磁共振成像、靶向给药等方面,为此,我们研究了磁性纳米粒子在Zn2+离子检测和核磁共振造影剂方面的应用。为此,我们写作本论文,并可将论文内容分为四个部分：1.简要介绍了黄酮类化合物的药理活性,并对其金属配合物的生物活性研究进展作系统概述；随之,我们对磁性纳米粒子的制备、功能化和生物医学应用简要概述。2.为寻求高效的抗癌药物和抗氧化剂,我们制备了一系列黄酮类化合物的希夫碱配体,并合成其过渡和稀土金属配合物,通过元素分析、红外光谱、紫外光谱、质谱、X单晶衍射等物理化学手段对结构加以表征。同时,我们对所合成的化合物的生物活性进行研究。通过紫外吸收光谱、荧光光谱和粘度法对这些化合物与DNA相互作用的机制和强度加以研究,实验发现,我们所合成的化合物可以与DNA以插入模式相互作用,且金属配合物与DNA的作用强度更高,说明它们都是良好的、具有较强活性的潜在的抗癌药物。我们通过对所合成化合物清除超氧自由基和羟基自由基的研究确定它们的抗氧化活性,实验发现,它们都是非常良好的抗氧化剂,而且金属配合物的抗氧化活性远远高于相应的配体。3.锌离子在细胞生物学以及细胞营养过程中起着非常重要的作用,对锌离子的检测很重要。我们通过高温热解法制备粒径单一的磁性四氧化三铁纳米粒子,通过高生物兼容性的聚乙二醇高聚物对其加以修饰,把喹啉类的锌离子探针连接在磁性纳米粒子的表面,从而制备一种水溶性良好的锌离子探针,而且基于磁性纳米粒子的超顺磁性作用,可以将探针有效地输送至生物体内特定部位来实现对特定部位的锌离子检测。对于锌离子探针的研究也为其他水溶性良好的纳米探针的研究及有毒离子的清除开辟了一条新的途径。4. Gd3+-DTPA是首个获得美国食品药物管理局批准的能够用于临床应用的MRI造影剂,它是T1型造影剂；四氧化三铁纳米粒子是一种新型有效的T2造影剂。我们通过高温热解法制备粒径单一的磁性四氧化三铁纳米粒子,通过高生物兼容性的聚乙二醇高聚物对其加以修饰,使其与钆基造影剂连接,从而制备新型的造影剂,一方面增强了其靶向性,另一方面使所合成的造影剂的纵向弛豫效率增强到62.58mM-1s-1。更多还原

【Abstract】 Flavonoids compounds were widely used in the fields of antitumor and antioxidative activity due to their special characteristics. Schiff base ligands and their metal complexes also possess a number of biological activities. Based on these reasons, we aimed to prepare some compounds with better biological activities. In this paper, we have synthesized and characterized a series of flavonoids Schiff base ligands and their metal complexes, including transition metal complexes and rare earth metal complexes. And we investigated their biological activities, such as DNA binding properties, antioxidant activities and so on. Magnetic nanoparticles are also applied in biomedicine area. They can be used as biological separation, ion sensors, magnetic resonance imaging contrast agent, drug delivery et al. And in this paper, we studied their uses on ions detection and magnetic resonance imaging contrast agent. The paper can be divided into four parts:1. A brief review on the biological activities of flavonoids and their metal complexes was given, and then the preparation, functionalization and biomedicine application of magnetic nanoparticles were summarized.2. In order to pursue more efficient antitumor drugs and antioxidants, we have prepared a series of flavonoids ligands and their metal complexes. Their structures were characterized by physicochemical methodologies, such as elemental analysis, infrared spectra, ultraviolet visible spectra, mass spectra, X single crystal diffraction and so on. We also investigated their biological activities. Their DNA binding mechanism and affinity were determined by ultraviolet visible titration, fluorescence spectra and viscosity measurements. Experimental results indicated that the flavonoids ligands and their metal complexes can intercalate into DNA base pairs, and the metal complexes can bind to DNA more strongly than the free ligands, showing that they are efficient potential antitumor drugs. In addition, we also studied the antioxidant activities of the ligand and their metal complexes by scavenging superoxide radical and hydroxyl radical effects in vitro, indicating that they are effective antioxidants and the antioxidant activity of the metal complexes is higher than that of the free ligand.3. Zinc ions are very important in the process of life, and the detection of zinc ions is also quite necessary. In this paper, we prepared the magnetic iron oxide nanoparticles via high-temperature decomposition of iron(III) acetylacetonate, and we functionalized them by high biological compatibility polyethyleneglycol derivatives. Quinoline derivatives were also coupled onto the surfaces of magnetic nanoparticles, and the new nanosensor was prepared. This kind of nanosensor can be used to detect zinc ions on the specific organs in aqueous media. The novel approach to devise nanosensor can be applied to design other water soluble nanosensors and eliminate toxic ions.4. Gd3+-DTPA is T1contrast agent, which is the first clinical MRI contrast agent; iron oxide nanoparticles are a kind of new T2contrast agents. We prepared the magnetic iron oxide nanoparticles via high-temperature decomposition of iron(III) acetylacetonate, and we functionalized them by high biological compatibility polyethyleneglycol derivatives. And the new contrast agent was prepared by coupling contrast agents based on gadolinium coordination compounds onto the surface of iron oxide nanoparticles. The new contrast agent not only enhanced the targeted ability of traditional contrast agents, but also increased the spin-lattice relaxation time to62.58mM-1s-1, which is almost8times as great as the traditional contrast agent, magnevist.更多还原