Four new phorbol diesters from Croton tiglium and their cytotoxic activities

Abstract Phytochemical investigation of the seeds of Croton tiglium resulted in the isolation and structure elucidation of four new 4-deoxy-4 β -phorbol diesters ( 1–4 ) named as 12- O -tiglylphorbol-4-deoxy-4 β -phorbol-13-acetate ( 1 ), 12- O -tiglylphorbol-4-deoxy-4 β -phorbol-13-hexadecanoate ( 2 ), 13- O -acetylphorbol-4-deoxy-4 β -phorbol-20-oleate ( 3 ) and 13- O -acetylphorbol-4-deoxy-4 β -phorbol-20-linoleate ( 4 ), respectively. The structures of the new compounds were established by 1D, 2D-NMR and HR-ESI–MS spectroscopic data and chemical degradation experiments. The cytotoxic activities of compounds 1–4 were evaluated against hepatic tumor cell lines (SNU387 and SNU398). Among these compounds, compound 4 exhibited the most potent activity against the SNU387 with IC 50 value of 0.71 μM.