芦荟大黄素在叶片中的分布及其在ZnO NPs作用下的光谱性质研究

发布时间：2018-06-01 11:30

本文选题：氧化锌 + 纳米粒子　；参考：《东北师范大学》2017年硕士论文

【摘要】：氧化锌纳米粒子(ZnO NPs)具有独特的理化性质,在不同领域都有重要的应用价值,这会导致它们被释放到不同的环境中,增加了与生物的相互作用,这是ZnO纳米粒子毒性影响中最重要的一方面。芦荟是百合科常绿多肉质草本植物,具有重要的观赏和药用价值,芦荟大黄素(Aloe emodin,AE)是芦荟中重要的色素分子,也是芦荟作为药用植物的重要有效成分。虽然有很多报道说明了ZnO纳米粒子作用在植物系统后产生的消极影响,但是就芦荟来说,ZnO纳米粒子对芦荟的毒性影响只是研究了其对芦荟原生质体活性的影响以及ZnO纳米粒子的浓度对芦荟原生质体外侧钙离子浓度的影响,至于ZnO纳米粒子对芦荟细胞内部生物活性物质的作用还不清楚。因此,本文主要研究了ZnO纳米粒子对芦荟叶片中重要的生物活性物质-芦荟大黄素的影响,结果发现ZnO纳米粒子会使芦荟大黄素溶液发生变色反应,而且芦荟大黄素的发光峰也发生了变化。首先,在荧光显微镜下观察到了芦荟大黄素在芦荟叶片中的纵向分布情况,这在之前的研究中是没有报道过的。通过徒手切片法制得芦荟叶片的纵向和横向切片,置于荧光显微镜下,分别在白光、蓝光和紫外光照射下观察叶片的结构,得到叶片的横切面和纵切面的显微图像。结果发现,芦荟叶片的纵切面经蓝光(460-490 nm)照射后,同化组织呈现红色,维管束发出亮黄色的荧光,呈带状分布在同化组织中。观察芦荟叶片的横切面,发现维管束鞘细胞中含有很多发亮黄色荧光的小球点,这些发亮黄色荧光的小球点的主要成分就是芦荟大黄素。其次,研究了ZnO纳米粒子作用下芦荟大黄素溶液颜色的变化情况。采用溶胶-凝胶的方法制备粒径5 nm左右的ZnO纳米粒子。分别配置成6 mg/L和10 mg/L的ZnO纳米粒子悬浮液,将其与新鲜提取的芦荟大黄素溶液作用,分别置于黑暗条件和紫外条件下,每隔一定时间记录混合液颜色的变化情况。结果发现无论在黑暗条件还是在紫外光照射的处理下,随着时间的增加,加入ZnO纳米粒子的芦荟大黄素溶液均发生变色反应。不同的是在紫外光的照射下,加入ZnO纳米粒子的芦荟大黄素溶液颜色变成橙红色,而在黑暗条件下则是橙色。可能是在紫外光处理下,ZnO纳米粒子水溶液发生光催化,表面产生的羟基和超氧自由基与芦荟大黄素发生氧化反应,使得芦荟大黄素苯环上的酚羟基等助色团的位置和数量发生变化,颜色由淡黄色向橙红色转变。最后,从光谱的角度研究了ZnO纳米粒子对芦荟大黄素溶液的作用。配置10 mg/L的ZnO纳米粒子悬浮液与相同浓度的芦荟大黄素水溶液混合作为实验组,将芦荟大黄素水溶液作为对照组,每间隔一定的时间测试它们的荧光光谱和吸收光谱。荧光光谱的结果显示,当激发光为460 nm时,ZnO纳米粒子与芦荟大黄素的混合液出现4个发光峰,分别是500 nm、540 nm、580 nm和630 nm。与未加ZnO纳米粒子的芦荟大黄素溶液比较,发现无论是否加ZnO纳米粒子,I540/I580比值均随溶液放置时间的增加而增加。但是加入ZnO纳米粒子可以加快I540/I580比值的增加。出现这种峰值的变化可能是因为芦荟大黄素的苯环上含有酚羟基和羰基,容易与溶液中产生于ZnO纳米粒子表面的活性氧基团发生变色反应。这些反应消除了ZnO纳米粒子表面的活性氧簇进而有助于减轻ZnO纳米粒子的生物毒性。关于ZnO纳米粒子作用下芦荟大黄素颜色变化的详细机理,我们将作进一步的分析和研究。这篇论文的结果对于进一步研究ZnO纳米粒子生物毒性的机理具有重要意义。
[Abstract]:Zinc Oxide nanoparticles (ZnO NPs) have unique physical and chemical properties and have important applications in different fields, which will lead to their release into different environments and increase the interaction with organisms. This is the most important aspect of the toxicity of ZnO nanoparticles. Aloe emodin (AE) is an important pigment molecule in Aloe and an important effective component of aloe as medicinal plant. Although many reports indicate the negative effects of ZnO nanoparticles on the plant system, the toxic effects of ZnO nanoparticles on Aloe Vera The effect of ZnO nanoparticles on the concentration of calcium ions in Aloe protoplasts was studied, and the effect of ZnO nanoparticles on the bioactive substances in Aloe cells was not clear. Therefore, the main biological activity of ZnO nanoparticles in aloe leaves was studied in this paper. The effect of sexual substance, aloe emodin, found that ZnO nanoparticles would change the color reaction of aloe emodin solution, and the luminescence peak of aloe emodin also changed. First, the longitudinal distribution of aloe emodin in aloe leaves was observed under the fluorescence microscope, which was not reported in previous studies. The longitudinal and transverse sections of the leaves of Aloe Vera were sectioned by hand sectioning. Under the fluorescence microscope, the structure of the leaves was observed under white light, blue light and ultraviolet light respectively, and the microscopic images of the transverse and longitudinal sections of the leaves were obtained. The results showed that the assimilate tissues were red after the blue light (460-490 nm) irradiated the longitudinal surface of the aloe leaves. The bright yellow fluorescence of the vascular bundles is distributed in the assimilated tissue. The transverse section of the leaves of the aloe vera is observed. It is found that there are many bright yellow fluorescent dots in the vascular sheath cells of the vascular bundle. The main component of the bright yellow fluorescent dots is the aloe emodin. Secondly, the aloe vera under the action of ZnO nanoparticles is studied. The change of the color of the prime solution. The ZnO nanoparticles with the diameter of 5 nm were prepared by the sol-gel method. The suspension of 6 mg/L and 10 mg/L of ZnO nanoparticles was arranged respectively. The solution was acted on the fresh aloe emodin solution, under the dark condition and the UV condition, and the color change of the mixture was recorded at a certain time. It is found that the aloe emodin solution which is added to ZnO nanoparticles has a discoloration reaction with the increase of time, both in dark and ultraviolet irradiation. The color of the aloe vera solution with ZnO nanoparticles is changed into orange red under ultraviolet light, but under the dark condition, It is orange. It is possible that under ultraviolet light treatment, the aqueous solution of ZnO nanoparticles is photocatalytic, and the hydroxyl and superoxide radicals produced on the surface oxidize with the aloe emodin, making the position and quantity of the phenol hydroxyl groups on the aloe emodin benzene ring change, the color changes from light yellow to orange red. Finally, from the spectrum The effect of ZnO nanoparticles on the aloe emodin solution was studied. A 10 mg/L ZnO nanoparticle suspension was mixed with the same concentration of aloe rhubarb aqueous solution as the experimental group. The aloe rhubarb aqueous solution was used as the control group. The fluorescence spectrum and absorption spectrum of the aqueous solution were measured at a certain time. The results of fluorescence spectra were measured. The results showed that when the stimulated luminescence was 460 nm, the mixture of ZnO nanoparticles and aloe emodin appeared 4 luminescence peaks, which were 500 nm, 540 nm, 580 nm and 630 nm., compared with the aloe emodin solution without ZnO nanoparticles. It was found that the I540/I580 ratio increased with the increase of the solution placement time whether or not ZnO nanoparticles were added. But the addition of Z was added to the Z. NO nanoparticles can accelerate the increase of the I540/I580 ratio, which may be due to the presence of phenolic hydroxyl and carbonyl groups on the benzene ring of the aloe emodin, which is easy to react with the reactive oxygen group produced on the surface of the ZnO nanoparticles. These reactions eliminate the reactive oxygen clusters on the surface of the ZnO nanoparticles and help them. In order to reduce the biological toxicity of ZnO nanoparticles, we will further analyze and study the detailed mechanism of the color change of ralotin in Aloe vera under the action of ZnO nanoparticles. The results of this paper are of great significance to the further study of the mechanism of the biological toxicity of ZnO nanoparticles.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q946;TB383.1

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