RESUMO
Objective To investigate the chemical constituents of the marine sponge Theonella swinhoei collected from the Xisha Islands in the South China Sea .Methods The petroleum ether and dichloromethane extract of the marine sponge T . swinhoei were purified by solvent extraction and chromatographic methods including vacuum liquid chromatography (VLC) , medium pressureliquidchromatography(MPLC),thinlayerchromatography(TLC)onsilicagel,highperformanceliquidchro-matography(HPLC) ,and Sephadex LH-20 .The chemical structures were determined by spectroscopic analysis and comparison with the reported data .Results Eight compounds were isolated and their structures were determined as cholest-7-ene-3β,5α, 6β-triol (1) ,ergosta-7 ,22-diene-3β,5α,6β-triol (2) ,25-norcycloartane-3β,6α,16β,24-tetraol (3) ,sinuflexibilin D (4) ,14-de-oxycrassin (5) ,N-(2-phenylethyl)-(9Z)-tetradecanamide(6) ,N-(2-phenylethyl)-tetradecanamide (7) ,7 ,8-dimethyl-isoallox-azine (8) .Conclusion Compounds 1～ 7 were isolated from the sponge of genus Theonella for the first time .