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.