【作者】 卢慧明；

【导师】 杨宇峰；

【作者基本信息】 暨南大学 ， 水生生物学， 2011， 博士

【摘要】 本文提取、分离和鉴定了大型海藻龙须菜(Gracilaria lemaneiformis)的化学成分,初步阐释了龙须菜对中肋骨条藻(Skeletonema costatum)化感作用机理。主要结果如下：利用多种吸附材料和分离方法(包括常压硅胶柱层析、反向硅胶柱层析、凝胶Sephadex LH-20柱层析、D101大孔树脂以及HPLC等),对龙须菜95%乙醇提取物进行了分离,共得到15个化合物并进行了结构鉴定。这些化合物包括3个糖脂类化合物：1-O-棕榈酸-3-O-β-D-吡半乳糖甘油酯(1-O-Palmitoyl-3-O-P-D-galactopyranosyl glycerol,1)、1-O-棕榈酸-2-O-棕榈油酸-3-O-p-D-吡喃半乳糖甘油酯(1-O-Palmitoyl-2-O-palmitoleoyl-3-O-β-D-galactopyranosyl glycerol,2)和1-O-棕榈酸-2-O-油酸-3-O-β-D-吡喃半乳糖甘油酯(1-O-Palmitoyl-2-O-oleoyl-3-O-β-D-galactopyranosyl glycerol,3);2个脂肪酸类化合物：棕榈酸(Palmitic acid,4)和亚油酸(Linoleic acid,5);2个核苷类化合物：尿嘧啶核苷(Uridine,6)和腺嘌呤核苷(Adenosine,7);3个酰胺类化合物：多鳞番荔枝酮(Squamolone,10)、2-亚乙基-3-甲基琥珀酰亚胺(2-ethylidene-3-methylsuccinimide,11)和N-苯乙基乙酰胺(N-Phenethylacetamide,12);2个酚类化合物：邻苯二甲酸丁酯异丁酯(Butylisobutyl phthalate,8)和1,4-二苄氧基苯酚(1,4-Dibenzoyloxybenzene,9);2个萜类化合物：黑麦草内酯(Loliolide,13)和3β-hydroxy-5α, 6a-epoxy-7-megastigmen-9-one (14)；1个其他类化合物：8-羟基-4E,6E-辛二烯-3-酮(8-Hydroxy-4E,6E-octadien-3-one,15)。所有化合物均首次从龙须菜中分离得到,其中,化合物8-Hydroxy-4E,6E-octadien-3-one (15)为新化合物。赤潮藻活性筛选实验结果表明,在分离得到的12种化合物中,亚油酸的抑制效果最好,亚油酸对中肋骨条藻的IC50值为23.17μmol/L;2-亚乙基-3-甲基琥珀酰亚胺的抑制效果最差,在浓度330μmol/L时,其抑制率仅达到19.8%,无法得出其ICso值。亚油酸对中肋骨条藻细胞增值有重要影响。高浓度组细胞的生长明显受到化感物质亚油酸的胁迫,100μmol/L浓度组在72 h时,其细胞密度仅为对照组的16%。较低浓度的亚油酸对中肋骨条藻的超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量在短时间内均有促进作用,随着亚油酸暴露时间的延长和浓度增大,中肋骨条藻超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量逐渐下降。亚油酸对中肋骨条藻细胞亚显微结构有重要影响。亚油酸可导致中肋骨条藻细胞膜、叶绿体、线粒体、细胞核等亚显微结构受到不同程度的破坏。更多还原

【Abstract】 Allelochemicals were extracted, isolated and identified from seaweed Gracilaria lemaneiformis. Preliminary allelopathy mechanism of the G. lemaneiformis on Skeletonema costatum was studied. The main results are as follows:In order to investigate the chemical constituents of G. lemaneiformis, a variety of absorbing materials and separation approaches (including pressure silica gel column chromatography, reverse silica gel column chromatography, Sephadex LH-20 gel column chromatography, D101 macroporous resin, and HPLC) were assessed. Fifteen compounds from G.lemaneiformis were isolated from the 95% ethanol extract by various column chromatographies. On the basis of various modern spectroscopic and literature data, fifteen compounds were identified, and one of them,8-Hydroxy-4E,6E-octadien-3-one was identified as a new compound. Fifteen compounds were isolated from G. lemaneiformis for the first time. Among these compounds, there are three Glycolipid compounds:1-O-Palmitoyl-3-O-β-D-galactopyranosyl glycerol (1),1-O-Palmitoyl-2-O-palmitoleoyl-3-O-β-D-galactopyranosyl glycerol (2),1-O-Palmitoyl-2-O-oleoyl-3-O-β-D-galactopyranosyl glycerol (3); two fatty acid compounds:Palmitic acid (4), Linoleic acid (5); two nucleosides:Uridine (6), Adenosine (7); three amides:Squamolone (10), 2-ethylidene-3-methylsuccinimide(11), N-Phenethylacetamide (12); two phenolic compounds: Butylisobutyl phthalate (8),1,4-Dibenzoyloxybenzene (9); two terpenoids:Loliolide (13), 3β-hydroxy-5α,6α-epoxy-7-megastigmen-9-one (14); one other compound: 8-Hydroxy-4E,6E-octadien-3-one (15).The inhibition of activity screening of allelochemicals on Skeletonema costatum showed that the strongest inhibitory allelochemical was Linoleic acid, and the lowest 2-ethylidene-3-methylsuccinimide. According to inhibition rate of different concentrations of linoleic acid on S. costatum, ICso value was 23.17μmol/L. While the inhibitory effect of 2-ethylidene-3-methylsuccinimide on S. costatum was only 19.8% at the concentration of 330μmol/L.The chloroplast, SOD, MDA and intracellular organelles of S. costatum were tested under external stress of linoleic acid. The result showed that when exposure to linoleic acid, the inhibition effect of linoleic acid on S. costatum increased at low concentration (1μmolL-1) and gradually decreased with the increase of the concentration and the extend of exposure time. After 72 h, the cell densities of S. costatum exposed to 100μmolL-1 of linoleic acid were 16% of the controls. The results showed that the SOD and MDA level were rapidly increased after a short exposure, and gradually decreased with the increase of the concentrations and culture time.The ultrastructure of algal cells was observed with transmission eletron microscopy (TEM). The results showed that linoleic acid damaged the cell membrane, chloroplast, mitochondria and nucleolus of S.costatum.更多还原