Purpose: To evaluate the effects of ebracteolatain A (EA) and ebracteolatain B (EB) from
Euphorbia ebracteolata
Hyata (Euphorbiaceae) on the proliferation of HepG2 cells and the possible mechanisms.
Methods: EA and EB from
E. ebracteolata were obtained by column chromatography. 3-(4,5-
Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays were used to
study the cytotoxic and pro-apoptotic activities of EA and EB against HepG2 cells. Western blot assay
was used to investigate the possible mechanisms of action.
Results: EA and EB were successfully isolated from
E. ebracteolata by column chromatography. The
results of MTT assay indicate that EA and EB have significant anti-proliferative activities against HepG2
cells in dose- and time-dependent manners with half maximal inhibitory concentration (IC
50) of 28.48
and 31.72 μg/mL. respectively. The results of flow cytometry assay suggest that EA and EB significantly
(p < 0.01) induced the apoptosis of HepG2 cells at the levels of 47.45 and 42.26 %, respectively.
Western blot data indicate that EA and EB significantly (p < 0.05 or 0.01) down-regulated the expression
levels of anti-apoptotic proteins (survivin and Bcl-2) and up-regulated the expression levels of proapoptotic
proteins (Smac, Bax, c-caspase-3 and c-caspase-9) in mitochondria-mediated apoptotic
pathway.
Conclusion: EA and EB inhibit the proliferation of HepG2 cells, the probable mechanisms being
associated with mitochondria-mediated apoptosis.
