壳寡糖，氨基葡萄糖及其衍生物的抗氧化功能研究

发布时间：2018-05-26 20:40

本文选题：壳寡糖 + 氧化应激　；参考：《中国海洋大学》2005年博士论文

【摘要】：机体在细胞有氧代谢过程中不断的产生自由基。在正常生理条件下,自由基不断的被清除。体内抗氧化防御体系包括酶解和非酶解两种机制。当异源性药物、毒物在体内的代谢过程中产生活性中间代谢产物,导致活性氧的过量产生,或者机体的防御体系受到损伤时,就会导致活性氧化应激状态。大量的研究资料表明氧化应激与很多疾病的发生密切相关。因此抗氧化剂及其作用机制的研究在医学上具有重要意义。还原型谷胱甘肽是机体最重要的非酶抗氧化剂,维持谷胱甘肽含量的稳态在很多病理过程中具有重要意义。L-半胱氨酸是提高GSH含量的主要途径,但是L-半胱氨酸在一定浓度时具有毒性而且容易被氧化,L-半胱氨酸前体化合物是有效的提高促进GSH合成,治疗氧化应激有关的疾病的有效手段。噻唑啉糖衍生物是L-半胱氨酸与糖类分子中的羰基缩合形成的环状化合物,它在体内能够通过非酶的水解反应释放出L-半胱氨酸,促进GSH的从头合成,提高GSH的含量,保护机体,具有广泛的生物学、医学功能。壳寡糖是通过甲壳素脱乙酰得到的,它具有生物相容性、可降解性、无免疫原性、无毒和易吸收等特点,在药物学,食品等领域具有非常广泛的应用。近年来壳寡糖抗氧化功能的研究备受关住,但是在这方面的研究还不多,对其抗氧化机制尚未充分研究,而且关于壳寡糖降解产生的单糖—氨基葡萄糖的抗氧化功能,目前国内外尚未见报导。本实验利用L-半胱氨酸和氨基葡萄糖,N-乙酰氨基葡萄糖制备了两种新的噻唑烷酸糖衍生物(GlcNH_2Cys,GlcNAcCys),对其熔点、比旋光、IR波谱和1H-NMR波谱进行了测定,结合两种已见报道合成的噻唑烷酸糖衍生物(GluCys,GalCys)的结构,比较并得出其结构为噻唑啉羧酸结构。本实验通过体外、体内实验研究壳寡糖,氨基葡萄糖及其衍生物的抗氧化、肝保护功能。利用体外试验方法研究了氨基葡萄糖及其衍生物的自由基清除能力,还原力,金属络合能力以及对羟自由基诱导的生物大分子如脂类、脱氧核糖和蛋白质的氧化性损伤的保护作用。利用四氯
[Abstract]:The body produces free radicals in the process of cell aerobic metabolism. Under normal physiological conditions, free radicals are constantly eliminated. Antioxidant defense system in vivo includes two mechanisms: enzymatic hydrolysis and non-enzymatic hydrolysis. When xenogeneic drugs and poisons produce active intermediate metabolites during metabolism in vivo, which results in excessive production of reactive oxygen species, or when the body's defense system is damaged, it will lead to active oxidative stress. A large number of studies have shown that oxidative stress is closely related to the occurrence of many diseases. Therefore, the study of antioxidant and its mechanism is of great significance in medicine. Reduced glutathione is the most important non-enzymatic antioxidant in the body. Maintaining the steady-state of glutathione content is of great significance in many pathological processes. L- cysteine is the main way to increase the content of GSH. However, L- cysteine is toxic at a certain concentration and can be easily oxidized. L- cysteine precursor compounds are an effective way to promote GSH synthesis and to treat oxidative stress-related diseases. Thiazolinose derivative is a cyclic compound formed by condensation of L-cysteine with carbonyl group in carboxylic molecules. It can release L-cysteine through non-enzymatic hydrolysis in vivo, promote the ab initio synthesis of GSH and increase the content of GSH. Protection of the body, with a wide range of biological and medical functions. Chitosan oligosaccharide is obtained by deacetylation of chitin. It has the characteristics of biocompatibility, biodegradability, non-immunogenicity, non-toxicity and easy absorption. It has been widely used in pharmaceutical, food and other fields. In recent years, the research on the antioxidation function of chitosan oligosaccharides is very close, but there are few researches in this field. The mechanism of antioxidation of chitosan oligosaccharides has not been fully studied, and the antioxidation function of monosaccharide-glucosamine produced by the degradation of chitosan oligosaccharides has not been fully studied. At present, no reports have been reported at home and abroad. In this paper, two new thiazolidate sugar derivatives, GlcNH2Cys2Cys-GlcNAcCysA, were prepared from L-cysteine and glucosamine N-acetylglucosamine. Their melting point, specific optical rotation IR spectra and 1H-NMR spectra were determined. The structure of two kinds of thiazolidate sugar derivative GluCys-GalCysA was compared and the structure of thiazoline carboxylic acid was obtained. The antioxidation and liver protection of chitosan, glucosamine and its derivatives were studied in vitro and in vivo. The free radical scavenging ability, reductive power, metal complexing ability of glucosamine and its derivatives were studied in vitro, and the biological macromolecules such as lipids induced by hydroxyl radical were studied. Protective effects of deoxyribose and protein on oxidative damage. Utilization of tetrachlo
【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2005
【分类号】：R341

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