Abstract: To study the chemical constituents of the dry Lapemis curtus, and the antioxidant activity of the isolated compounds.The seven compounds were isolated and purified from the dry Lapemis curtus using different kinds of column chromatography.Their structures were determined as cholesterol (1), 5,6β-Epoxysitosteryl oleate (2), 9-Octadecenoic acid (9Z)-, (2R)-2,3-bis[(1-oxooctadecyl)oxy] propyl ester (3),1-methylhydantoin (4), α-palmityl glycerin ether (5),Chimyl alcohol (6), 7α-methoxyl-β-sitosterol (7) onthe basis of the physicochemical properties and spectral analysis.Compounds 2,3,5,6 and 7 were isolated from the dry Lapemis curtus for the first time.All compounds show weak antioxidant activity by DPPH method.

Key words: Lapemis curtus, marine organism, chemical constituents, antioxidant activity