【作者】 陶洪文；

【导师】 朱伟明；

【作者基本信息】 中国海洋大学 ， 药物化学， 2009， 博士

【摘要】 当前药物先导物发现手段主要是天然来源化学实体筛选和以组合化学为主的化学筛选两个途径。由于来源于天然产物的化合物化学和生物活性多样性,远远超出组合化学筛选化合物的多样性,天然药物先导化合物仍具有基于已有化学骨架的组合筛选所不能相提并论的优势。Newman等在2009年的最新统计结果更进一步证实了这一点,01/1981-10/2008期间所获准审批进入临床的1024个小分子新药中,直接或间接来自天然产物的药物占到63%,可见天然药物研究仍是新药发现不可替代的方式[1]。本论文系统开展了三种药用植物的活性成分及厚藤共生真菌的活性代谢产物研究,以期阐明其有效成分并获得新的药物先导化合物、从化学角度探讨其共生关系并获得活性成分的微生物来源;同时开展对量大天然成分的化学修饰,以期获得新的药物先导化合物。论文的研究内容包括三个部分:①药用植物厚藤(Ipomoea pes-caprae)、泽漆(Euphorbia helioscopia)及肉豆蔻(Myristica fragrans)的活性成分研究;②厚藤共生真菌的分离、TLC和HPLC-UV相结合检测代谢产物的化学特征及其多样性,筛选发现与宿主植物化学成分相关的菌株和“天才菌株(Talented Strains)”及其活性代谢产物研究;③泽漆二萜成分的化学修饰及其构效关系探讨。取得的主要研究成果有:1.从三种药用植物中分离纯化了45个单体化合物,通过核磁共振光谱(1D-NMR, 2D-NMR)、质谱、紫外光谱、气质联用(GC-MS)及单晶衍射等天然产物结构鉴定技术,结合化学反应鉴定了43个化学结构,均得到其特征化学成分;获得新化合物14个(1–8, 16, 30–34):8个树脂糖苷类化合物(1–8)、1个麻枫树烷型二萜(16)和5个由二苯基壬酮和新木酚素通过碳碳单键偶联而成的新骨架化合物(30–34)。通过对部分化合物的生物活性的初步研究,发现了6个细胞毒活性化合物(16, 17, 32, 33, 36, 39)、13个抗氧化活性化合物(29–40, 42)。2.从新鲜的厚藤植物中分离纯化了18株共生真菌,发现了一株高产抗肿瘤活性化合物——二氧吗啉生物碱的工程菌株:尖孢镰刀菌Fusarium oxysporum J8-1-2,该生物碱占乙酸乙酯提取代谢产物的27.3%,其对人白血病细胞HL-60和人肺癌细胞A-549表现出良好的细胞毒活性(IC50值分别为1.2和2.3μg/mL);从另外两株共生真菌Y16和球茎状镰孢菌Fusarium oxysporum Y24-2的发酵产物中分离鉴定了12个化合物的化学结构,获得6个新化合物(47, 49, 50, 52, 53, 56)——3个二苯基丁内酯(47, 49, 50)和3个麦角甾酮类(52, 53, 56)化合物,通过抗氧化活性测试,发现4个良好的抗氧化活性化合物(46, 48, 49, 50)。从菌株Y16中发现与宿主植物化学成分具有相同生源途经的化合物,并进行了生物合成途经推测。3.对泽漆的大量无活性二萜化学成分Euphorin进行了结构修饰,制备了11个结构新颖的衍生物(R1–R3, M1-1, M2B-1, T1-1, T1-2, T2B-1, T2C-1, T2A-2, T2B-2),其中3个衍生物具有细胞毒活性(R3, T2B-1和T2A-2)。总之,本文通过药用植物厚藤、泽漆及肉豆蔻的活性成分研究、厚藤共生真菌的活性代谢产物研究及对泽漆化学成分的化学修饰,获得了68个单体化合物,阐明了其中66个化学结构,新化合物31个、活性化合物23个;获得了一株与产宿主植物化学成分具有相同生源途经的化合物共生真菌,并进行了代谢产物生物合成途经相关性推测,为进一步研究该植物的微生物共生关系提供了初步的线索;获得了一株盛产活性生物碱的工程菌株,为其进一步开发研究确定了初步的化学物质基础,为新药研究提供了新的筛选化合物资源和微生物资源,为从非活性天然产物开发为活性化合物提供了参考。更多还原

【Abstract】 Medicinal animals and plants are the major sources of lead compounds. However, some of them are on the edge of extinction owing to over-exploitments and environment deterioration. The medicinal resource conservation and the drug supply became the key of the drug R & D. Secondary metabolite of micro-organisms and the chemical modification and synthesis of chemical ingredients were considered as two feasible ways to discover the new drug sources because of their sampling in small quantity, reproduction speed, little ecological damage, and easy achievement of large-scale production.Our study focused on the effective chemical ingredients of medicinal plants and the bioactive compounds of endophytic fungi to obtain the structurally novel and bioactive compounds. Furthermor, we attempted to modify the strutures of the components from medicinal plants to get the bioactive derivatives. This dissertation contents of three sections: i. Investigations of effective components from Ipomoea pes-caprae, Euphorbia helioscopia and Myristica fragrans; ii. Screening of talented strains and study on bioactive compounds of endophytic fungi from Ipomoea pes-caprae by integrated TLC and HPLC-UV methods. iii. Chemical modifications of euphorin from Euphorbia helioscopia by introducing a bioactive moiety——N- benzoyl-(2R,3S)-3-phenylisoserine or N-tertiary butyloxycarbonyl-(2R, 3S)-3-phenyl- isoserine, and biological evaluation and SAQR analysis of the derivatives.As the results, compounds 1–13 from Ipomoea pes-caprae, compounds 16–28 from Euphorbia helioscopia, and compounds 29–45 from Myristica fragrans were isolated and identified by spectroscopic and the chemical methods, among which 14 compounds (1–8, 16, 30–34) were the new structures and 5 compounds (30–34) were novel structures with a diarylnononoid and a neoligan moieties. Six of them exhibited cytotoxic activities on a panel of cancer cells, and thirteen compounds owned anti-oxidative effect against DPPH. 18 Strains of endophytic fungi were isolated from Ipomoea pes-caprae, and one of them that was indentified as Fusarium oxysporum J8-1-2 is an engineering strain producing a cytotoxic alkaloid (compound 55, 27.3% yield) against HL-60 and A-549 cells with IC50 values of 1.2 and 2.3μg/mL, respectively. The metabolites of another two endophytic fungi, Y16 and Fusarium oxysporum Y24-2, were studied. Six new compounds (47, 49, 50, 52, 53) together with 4 known ones (46, 48, 51, 54) from Y16, and a new compound (56) together with 2 known ones (28 and 57) from Fusarium oxysporum Y24-2 were isolated and identified. The new compounds included three butyrolactone derivatives (47, 49, 50) and three ergosterones (52, 53, 56). Eleven new jatrophane diterpence derivatives (R1–R3, M1-1, M2B-1, T1-1, T1-2, T2B-1, T2C-1, T2A-2, T2B-2) with taxol and docetaxel side groups were obtained by chemical modification on euphorin, and three derivatives (R2, T2B-1 and T2A-2) of them exhibited ctotoxicity against HL-60 and A-549 cell lines.In summary, 31 new compounds and 35 known ones were obtained in this dissertation, and 23 of these compounds showed cytotoxic and antioxidative activities.更多还原