长棘海星的体内脂肪酸成分及其生物学意义分析

 长棘海星是热带和亚热带海域珊瑚的最重要捕食者。首次报道了长棘海星体内总脂肪酸的提取方法及其成分与含量测定。用石油醚提取低极性组分，经硅胶柱层析分离得到游离脂肪酸（酯）；用乙酸乙酯提取酯溶性神经酰胺及其衍生脂类，提取物和残余的水溶性脂类分别经盐酸甲醇解，水解产物再用石油醚提取。各提取及分离组分经GC MS分析，发现游离脂肪酸中有C14～C20的长链饱和与不饱和脂肪酸，其中二十碳的Ω-3和Ω-6多价不饱和脂肪酸含量高，如：5,8,11,14-二十碳四烯酸甲酯（主要），8,11,14-二十碳三烯酸，5,8,11,14,17 -二十碳五烯酸甲酯。在盐酸甲醇解产物中，主要检测到系列饱和脂肪酸和高含量的甾醇成分。多价不饱和脂肪酸是维持细胞膜结构和功能的必要组分，也是合成其它生理活性物质的前体化合物。据报道不饱和脂肪酸5,8,11,14-二十碳四烯酸也有诱发长棘海星捕食反应的作用。5,8,11,14-二十碳四烯酸是长棘海星体内主要的必需不饱和脂肪酸，长棘海星体内可能无法合成它，所以必须不断地捕食含有该不饱和脂肪酸的珊瑚。本实验脂肪酸（酯）的分极性段提取处理方法，能充分地提取出脂肪酸成分，排除其它成分的干扰，分析结果可靠，且重现性好。研究发现长棘海星体内有高含量的、具有重要应用价值的多价不饱和脂肪酸和甾体激素，这也为长棘海星的合理开发与利用提供了依据。

Chemical Constituents and Its Biological Aanalyses of the Fatty Acids from the Whole Body of Starfish Acanthaster planci

In the tropical and subtropical ocean, the starfish Acanthaster planci was notorious for destroying coral. In this paper, we reported the extract, chemical constituent and content of fatty acids from the whole body of Acanthaster planci. The free fatty acids were extracted with petroleum ether and were separated on silicon gel column chromatography. The ethyl acetate-soluble lipid fraction and water-soluble lipid fraction were subjected to hydrochloric acid-catalyzed methanolysis, then were extracted with petroleum ether, respectively. Based on the GC-MS analysis, a series of C14~C20 saturated and unsaturated fatty acids were identified in free fatty acids. Prolific omega 3 and omega 6 polyunsaturated fatty acids were composed of 5,8,11,14-eicosatetraenoic acid methyl ester (major), 8,11,14-eicosatrienoic acid and 5,8,11,14,17- eicosapentaenoic acid methyl ester. Saturated fatty acids and high content steroids were found in the extracts of methanolysis products. The omega fatty acids are the major building blocks of cellular membranes, and they keep the cell membrane optimally fluid. The omegas can convert to hormone like substances that influence metabolic activities. 5,8,11,14-eicosatetraenoic acid, which was previously found as feeding attractant, is the primary essential fatty acid of the starfish Acanthaster planci. It is postulated that eicosatetraenoic acid cannot be constructed within the body of starfish Acanthaster planci from other components by any known biosynthetic pathways, and therefore must be obtained from the diet. The effective methods used to extract the fatty acids according to their polarity respectively excluded interferes of other structural type components and gained perfect isolation and identification results with high accuracy and good repeatability in GC-MS experiments. The finding of high content of polyunsaturated fatty acids and bioactive steroids with promising application in the fields of drug and food industry will also provide useful information for further researches and exploitation on the starfish Acanthaster planci.