黄槿内生真菌赤散囊菌及红海榄的次生代谢产物及其生物活性研究

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	黄槿内生真菌赤散囊菌及红海榄的次生代谢产物及其生物活性研究
其他题名	Secondary Metabolites and Their Bioactivities of a Hibiscus tiliaceus-Derived Endophytic Fungus Eurotium rubrum and a Mangrove Plant Rhizophora stylosa Griff.
	李冬利
学位类型	博士
	2008-05-23
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	红树林内生真菌赤散囊菌黄槿红海榄化学成分生物活性
摘要	由于生长环境的特殊性，红树林及其内生真菌的代谢产物在化学类型和生物活性方面都具有多样性，因此对其代谢产物的研究引起了人们越来越多的关注。本论文以菌丝体生物量、代谢产物量等指标及薄层色谱分析、高效液相色谱分析、抗菌活性测试等筛选手段对来源于我国海南红树植物的九株内生真菌在四种不同液体培养基上的静置发酵产物进行了综合评价，并从中选择了来源于半红树植物黄槿（Hibiscus tiliaceus）的内生真菌G2——赤散囊菌（Eurotium rubrum）进行了30 L规模发酵（采用PDB培养基）和次生代谢产物的研究，对分离得到的部分化合物进行了初步的生物活性评价。此外，本论文还对海南真红树植物红海榄（Rhizophora stylosa Griff.）的化学成分进行了研究，并对分离得到的部分化合物进行了二苯代苦味酰自由基（DPPH）清除活性的评价。采用常规的硅胶柱层析、Sephadex LH-20柱层析、反相硅胶柱层析、制备薄层层析（pTLC）、重结晶等分离手段，分离纯化得到单体化合物。综合运用现代波谱技术 (IR、UV、MS、1D-NMR 和 2D-NMR) 以及与标准品或文献比对鉴定单体化合物的结构。从G2菌丝体和发酵液的合并提取物中鉴定了45个化合物的结构，其中13个为新化合物，结构类型包括6个苯甲醛类化合物（ER1~ER6）、4个蒽醌类化合物（ER15~ ER18）和3个含吲哚的二酮哌嗪生物碱类化合物（ER27~ER29）。对以上分离鉴定的部分单体化合物进行了DPPH自由基清除活性、拒食杀虫活性、抗细菌活性以及体外细胞毒活性的初步评价。新化合物ER15和三个已知化合物ER20、ER39和ER40都表现很强的DPPH自由基清除活性。化合物ER15还表现较好的拒食杀虫活性，而化合物ER5和ER18不但没有杀虫活性，反而能促进幼虫的生长。所测试的化合物只有ER15和ER18表现出微弱的抗金黄色葡萄球菌活性。所测试的化合物对A-549、HL-60和P-388细胞株均未表现出有意义的体外细胞毒活性。从红海榄枝条的提取物中分离鉴定了29个化合物，其中2个为新化合物，包括1个三萜酯（RS1）和1个黄烷醇类化合物（RS12）；另有1个三萜酯（RS5）和1个黄烷醇类化合物（RS11）作为新的天然产物被分离鉴定。对从红海榄提取物乙酸乙酯相和正丁醇相分离得到的部分单体化合物进行了DPPH自由基清除活性的研究。黄烷醇类化合物RS16和RS17显示最强的活性。另外，实验结果说明黄烷醇类化合物的DPPH自由基清除活性与其分子中所含的羟基数目有一定关系，而且若芳香环上有多个邻位酚羟基，则该化合物的活性将增强。本论文实验结果为海南红海榄植物资源的利用提供了化学成分及抗氧化活性方面的科学依据。
其他摘要	Mangrove plants are distributed in most tropical and subtropical coastal regions of the world. Some of them have been proven to be a rich source of structural interesting and biological active secondary metabolites. Furthermore, because of their ecosystems that straddled the land and the sea, from freshwater to seawater, mangrove plants are found to be resources of abundant distinct microorganism species including mutualistic fungal endophytes. Mangrove-derived fungi have drawn the interest of more and more natural product chemists as a rich source of structurally unique natural products with a wide range of biological activities. In this dissertation, the static fermentation extracts of 9 endophytic fungal strains derived from mangrove plants on 4 different kinds of liquid cultural mediums, were comprehensively evaluated on the basis of mycelia’ biomass, weight of fermentation extracts, antimicrobial activities, and the results of TLC and HPLC analysis. As a result, a strain G2 Eurotium rubrum (isolated from the inner tissue of the semi-mangrove plant Hibiscus tiliaceus) was selected as aimed strain to be inoculated into 30 L of PDB medium for further investigation of its secondary metabolites. Some of the isolated compounds were evaluated for their bioactivities. Additionally, this dissertation also describes the isolation, structure elucidation of chemical constituents from the mangrove plant Rhizophora stylosa Griff., as well as the DPPH radical scavenging activity of some isolated compounds. The compounds were isolated by repeated column chromatography (CC) on silica gel, RP-18, and Sephadex LH-20, as well as by preparative thin layer chromatography (pTLC) and recrystallization. The structures of these compounds were elucidated by means of spectroscopic methods including IR, UV, MS, 1D-NMR and 2D-NMR, as well as compared with reference materials or literatures. Totally, 45 compounds were isolated and structurally elucidated from the extract of Eurotium rubrum G2. Among them, 13 were found to be new structures, including 6 new benzaldehyde derivatives (ER1~ER6), 4 new anthraquinone derivatives (ER15~ER18), and 3 new dioxopiperazine alkaloids (ER27~ER29). Some of the isolated pure compounds were evaluated for their DPPH radical scavenging activity, insecticidal activity, antibacterial and cytotoxic activity. In DPPH radical scavenging assay, ER15, ER20, ER39, and ER40 showed strong activity. In insecticidal assay, ER15 exhibited moderate insecticidal activity towards neonate larvae of the pest insect Spodoptera littoralis, while ER5* and ER18* did not show any insecticidal activity but seemed to have ability to promote the larvae’s growth. It was revealed that the new compounds ER15* and ER18* exhibited weak inhibitory activity against Staphylococcus aureus. None of the tested compounds showed remarkable activity in the in vitro cytotoxic assay against tumor cell lines A-549, HL-60, and P-388. Chemical investigation of the stems and twigs of R. stylosa afforded 29 compounds. Among them, 2 were found to be new structures, including 1 pentacyclic triterpenoid ester (RS1) and 1 flavanol derivative (RS12). Additionally, 1 pentacyclic triterpenoid ester (RS5) and 1 flavanol derivative (RS11) were isolated and elucidated as natural substance for the first time. The DPPH radical scavenging activity of some isolated compounds from EtOAc-soluble fraction and n-BuOH-soluble fraction of R. stylosa was studied. Flavanol derivatives RS16 and RS17 showed strongest activity. Moreover, the results revealed that the DPPH radical scavenging activity of flavanol derivatives seemed to be related to the number of phenol groups. Further data analysis revealed that compounds having adjacent hydroxyl groups on the ring-B possessed higher activity.
页数	128
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/889
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	李冬利. 黄槿内生真菌赤散囊菌及红海榄的次生代谢产物及其生物活性研究[D]. 海洋研究所. 中国科学院海洋研究所,2008.

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