Abstract:Six compounds were isolated from the ethanol extract of mangrove plant Scyphiphora hydrophyllacea Gaertn. F. Their structures were identified as betulone (1), 3,4,5-trimethoxyphenol-β-D-glucopyranoside (2), α-amyrin (3), β-amyrin (4), β-sitosterol (5), and stigmasterol (6) by spectroscopic evidence (IR, NMR, MS, etc.) and comparision of their spectral data with those of the literatures. The cytotoxicty of all the compounds were tested by MTT assay, and compound 1 showed inhibitory activity towards human hepatoma cellline SMMC-7721 with the IC50 value of 12.5 μg ml-1.