水溶性壳聚糖衍生物的取代基团及氨基正电性对抑菌活性的影响

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	水溶性壳聚糖衍生物的取代基团及氨基正电性对抑菌活性的影响
其他题名	Influence of grafted groups and amino cation on the antifungal activity of water-soluble chitosan derivatives
	郭占勇
学位类型	博士
	2007-06-02
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	壳聚糖衍生物取代基团氨基正电性抑菌活性机理
摘要	壳聚糖是一种天然的聚阳离子多糖，可以从甲壳类动物、菌类、昆虫等自然资源中提取得到。壳聚糖具有良好的生物相容性，天然无毒，可生物降解，从而在生物工程、制药、化妆品、纺织品、农业等领域引起了广泛关注。随着对壳聚糖以及壳聚糖衍生物研究的深入，壳聚糖的抑菌活性由于农业杀菌剂的环境问题和抗药性问题的出现而得到重视。但是，对于壳聚糖抑菌活性的研究大都集中于壳聚糖的分子量和脱乙酰度对其活性的影响，而相应的壳聚糖衍生物很少。本文合成了羧甲基壳聚糖希夫碱，N-取代羧甲基壳聚糖，脲取代羧甲基壳聚糖，壳聚糖季铵盐以及羧甲基壳聚糖季铵盐，并对它们的抑菌活性进行了研究，同时探讨了导入基团与抑菌活性间的构效关系。羧甲基壳聚糖希夫碱对苹果腐烂病菌、番茄早疫病菌和棉花枯萎病菌的抑制活性研究结果表明2-（2-羟基-5-硝基苯亚胺基）羧甲基壳聚糖和2-（2-羟基-5-氯苯亚胺基）羧甲基壳聚糖的抑菌活性高于壳聚糖、羧甲基壳聚糖和2-（2-羟基苯亚胺基）羧甲基壳聚糖，原因可能是2-羟基-5-硝基苯亚胺基和2-羟基-5-氯苯亚胺基两个活性基团的引入。对番茄早疫病菌和苹果轮纹病菌的抑制效果表明，N-取代羧甲基壳聚糖的抑菌活性低于壳聚糖和羧甲基壳聚糖，脲取代羧甲基壳聚糖的抑菌活性高于羧甲基壳聚糖。测定了壳聚糖季铵盐对灰葡萄孢以及炭疽病菌的抑制活性，结果表明壳聚糖季铵盐的抑制活性高于壳聚糖。因为壳聚糖分子的正电荷可以和菌体细胞壁的负离子相互结合，从而导致菌体死亡，而壳聚糖季铵盐分子中明显的正电性可以促进这种结合能力，从而更进一步的增强抑菌活性。由于相同的原因，抑菌活性随着正电荷的增强而增强，与此同时，高分子量壳聚糖季铵盐由于其较大的体积而具有比低分子量壳聚糖季铵盐更高的抑菌活性。为了进一步验证氨基的正电性与抑菌活性的关系，合成了羧甲基壳聚糖季铵盐并对这类衍生物对灰葡萄孢和炭疽病菌的抑制活性进行了测定，结果表明，羧甲基壳聚糖季铵盐的抑菌活性高于羧甲基壳聚糖，且部分羧甲基壳聚糖季铵盐的抑菌活性高于壳聚糖。500μg/mL时，N-(2-羟基-5-硝基苯亚甲基）-N,N-二甲基羧甲基壳聚糖和N-(2-羟基-5-氯苯亚甲基）-N,N-二甲基羧甲基壳聚糖对苹果轮纹病菌的抑制率都达到100%。壳聚糖季铵盐中正电荷在抑菌活性中的作用再一次被证实。
其他摘要	Chitosan is a natural cationic aminopolysaccharide copolymer of glucosamine and N-acetylglucosamine. It can be easily obtained from the natural resource, such as crustacean animals, fungi and insects. And it has a number of unique properties such as biocompatibility, biodegradability, and non-toxicity, which have attracted much attention in the field of biotechnology, pharmaceutics, cosmetics, textiles, agriculture, etc. With the development of study on the science of chitosan and chitosan derivatives, the antifungal activity of chitosan has received considerable interests. But, the most concentration was put on the molecular weight and degree of deacetylation of chitosan, which affect the antifungal activity, little work has been reported on the antifungal activity of chitosan derivatives. In this paper, Schiff bases of carboxymethyl chitosan (CMCTS), N-substituted CMCTS, urea-substituted CMCTS, quaternized chitosan and quaternized CMCTS were synthesized, and their antifungal activity was assessed. Antifungal activity of Schiff bases of CMCTS against Valsa mali (V. mali), Alternaria solani (A. solani) and Fusarium oxysporium f. sp. Vasinfectum (F. oxysporium f. sp. Vasinfectum) was assessed according to earlier method in vitro. The results indicated that 2-(2-hydroxyl-5-nitrobenzaldimino)-CMCTS and 2-(2-hydroxyl-5-chlorobenzaldimino)-CMCTS had better antifungal activity than chitosan, CMCTS, and 2-(2-hydroxybenzaldimino)-CMCTS. And the reason is the groups of 2-hydroxyl-5-nitrobenzaldimino and 2-hydroxyl-5-chlorobenzaldimino grafted to chitosan; N-substituted CMCTS derivatives had less antifungal activity against Alternaria Solani and Physalospora piricola Nose than chitosan and CMCTS; urea-substituted CMCTS derivatives had better antifungal activity against Alternaria Solani and Physalospora piricola Nose than CMCTS. Antifungal activity of quaternized chitosan against Botrytis cinerea Pers. (B. cinerea pers.) and Colletotrichum lagenarium (Pass) Ell.et halst (C. lagenarium (Pass) Ell.et halst) was assessed. The result indicated that quaternized chitosan had better antifungal activity than chitosan. Because the target site of the cation of chitosan is the negatively charged cell surface membrane, strong cation of quaternized chitosan can increase the antifungal activity. And so, the activity was increased when electronegative groups were grafted for the same reason. High molecular weight chitosan has better antifungal activity than low molecular weight chitosan because of the big volume. In order to prove the conclusion above-mentioned, quaternized CMCTS were synthesized and their antifungal activity against B. cinerea pers. and C. lagenarium (Pass) Ell.et halst was assessed. Quaternized CMCTS have better antifungal activity than CMCTS, and part of the quaternized CMCTS derivatives have better antifungal activity than chitosan. At the concentration of 500μg/mL, N-(2-hydroxy-5-nitrylbenzal)-N, N-dimethyl CMCTS and N-(2-hydroxy-5-chlorobenzal)-N, N- dimethyl CMCTS can inhibit the growth of Physalospora piricola Nose completely. The effect of the cation of chitosan and quaternized chitosan (or CMCTS) is proved again.
页数	94
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/1287
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	郭占勇. 水溶性壳聚糖衍生物的取代基团及氨基正电性对抑菌活性的影响[D]. 海洋研究所. 中国科学院海洋研究所,2007.

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