Five steroidal glycsides (1)～(5) have been isolated from the soft coral Lobophytum sp. , collected from Sanya Bay, Hainan Island. Base on the spectroscopic methods, their structures were determined to be 3'-O-acetyl-4-O-[β-D-xylo- pyranosyl-oxy]-pregn-20-en-3β, 4α-diol (1), 4-O-[β-D-xylo- pyranosyloxy]-pregn-20-en-β, 4α-diol (2), 4'-O- acetyl-4-O- [β-D-xylo-pyranosyl-oxy]-pregn-20-en-3β, 4α-diol(3), 4'-O-acetyl-4-O-[β-D-arabino-pyranosyl-oxy]-pregn-20-en-3β, 4α- diol (4), and 4-O-[β-D-arabinopyranosyl-oxy]-pregn-20-en- 3β, 4α- diol (5). Among them, 1 is a new compound. Bioassay showed that 1, 2 and 5 displayed cytotoxicity against human SKMG-4, Hep-G2 and CNE2 cell lines in vitro.

Key words: CYTOTOXICITY TEST, STEROL, SPECTROMETRIC ANALYSIS, GLYCOSIDE, SOFT CORAL, METABOLITE