【作者】 李昉；

【导师】 王斌贵；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋化学， 2008， 博士

【摘要】 本论文对民间药用红树植物木榄(Bruguiera gymnorrhiza)中的次生代谢产物进行了研究,同时还对分离自似瘤凹顶藻(Laurencia similis Namet Saito)的内生真菌EN21(Exophiala oligosperma)进行了化学成分研究。对分离得到的部分化合物进行了初步的DPPH自由基清除活性和抗菌活性筛选。采用常规的硅胶柱层析、反相硅胶柱层析、制备薄层层析、凝胶Sephadex LH-20柱层析、半制备型高效液相色谱(HPLC)以及重结晶等手段,从木榄(Bruguiera gymnorrhiza)中分离得到23个化合物;从EN21(Exophiala oligosperma)中分离得到23个化合物。利用一维、二维核磁、质谱、元素分析等各种现代波谱技术及化学反应方法,确定了木榄中20个化合物的结构,包括黄酮单体化合物5个,三萜类化合物11个,甾体化合物2个,长链烷烃2个,其中4个化合物为首次从木榄中报道的黄酮;确定了EN-21中20个化合物的结构,其中脑苷脂1个,甾体化合物7个,芳环化合物3个,三萜类化合物2个,包括1个新天然产物。本文系首次报道Exophiala oligosperma的化学成分。对从木榄中分离得到的部分化合物进行了DPPH自由基清除活性筛选,发现黄酮类化合物BRG-1、BRG-2、BRG-3、BRG-4显示了较强的DPPH自由基清除活性,而三萜类化合物则未表现出DPPH自由基清除活性。抗菌筛选实验中所有测试样品未显示出活性。研究结果充实了红树林植物和海藻内生真菌代谢产物的内容,为其有效利用提供了一定的科学依据。更多还原

【Abstract】 This dissertation describes the investigation of the chemical constituents of a mangrove plant Bruguiera gymnorrhiza, aiming to find out the correlation between the metabolites and its folk medical uses. Furthermore, the chemical composition of a marine algous endophytic fungus EN21 ( Exophiala oligosperma ) which was isolated from Laurencia similis Namet Saito, was also carried out. The DPPH-radical scavenging and antibacterial activity of some isolated compounds from Bruguiera gymnorrhiza were evaluated .The compounds were separated from the organic solvents extracts by repeated column chromatography (CC) on silica gel, RP-18, preparative thin layer chromatography (PTLC) and Sephadex LH-20, as well as by semi-preparative HPLC and recrystallization. The structures of the isolated compounds were elucidated by means of modern spectroscopic methods including 1D-NMR (1H-NMR, 13C-NMR, DEPT) and 2D-NMR (1H-1H COSY, HMBC, HMQC), EI-MS, FAB-MS, as well as by chemical method. A total of 46 compounds were separated from the two organisms. From Bruguiera gymnorrhiza, 23 compounds were isolated with 20 of them were structurally elucidated, while from endophytic fungus EN21, 23 compounds were obtained with 20 of them were structurally elucidated. Among them, one compound ( EN21-2 ) was found to be firstly separated from natural resources and 4 flavonoids were isolated from Bruguiera gymnorrhiza for the first time. In addition, this is the first chemical investigation on Exophiala oligosperma(EN21).The test of DPPH radical scavenging activity was carried out on some of the pure compounds isolated from Bruguiera gymnorrhiza. The result revealed that flavonoids BRG-1、BRG-2、BRG-3 and BRG-4 possessing higher activity. However, none of the triterpenes showed any activity. In addition, none of the tested compounds showed any antibacterial activity.更多还原