Pentacyclic triterpenoids and their cytotoxicity from the stem bark of Styrax japonica S. et Z.

The methylene chloride soluble fraction of MeOH extract from the stem bark of Styrax japonica S. et Z. (Styracaceae) showed significant cytotoxicity by SRB method against five human tumor cell lines. Four known pentacyclic triterpenoids, oleanolic aldehyde acetate (1), erythrodiol-3-acetate (2), euphorginol (3), and anhydrosophoradiol-3-acetate (4) were isolated by activity-guided fractionation. Their structures were determined by chemical and spectral analysis. Compounds 1-4 were isolated from S. japonica for the first time.