OBJECTIVE:To investigate the mechanism underlying the anticancer effect of Artemisia species through the inhibition of cell growth and induction of apoptosis in breast carcinoma cells.METHODS:To evaluate the anticancer activity of methanol extracts of eight Artemisia species(Artemisia stolonifera,Artemisia selengensis,Artemisia japonica,Artemisia Montana,Artemisia capillaris,Artemisia sylvatica,Artemisia keiskeana,and Artemisia scoparia),we first investigated the proliferation of estrogen receptor(ER)-positive MCF-7breast carcinoma cells exposed to 5 or 200 g/mL for72 h.Apoptosis induction was assessed by an Annexin V binding assay in cells exposed to extracts at a high concentration(200 g/mL).To verify the mechanism of apoptosis,ER expression and its related signaling was investigated using an immunoblot assay under the same conditions.RESULTS:MCF-7 cells showed the strongest antiproliferative response to the tested extracts.Howev-er,a biphasic effect was observed:the extracts inhibited proliferation at high concentrations whereas they stimulated it at low ones.ER expression was similarly modulated by the extracts.However,all of the extracts induced apoptosis at a high concentration(200 g/mL).Compared to the control level,exposure to the extracts resulted in a remarkable increase in the shift of cell populations.CONCLUSION:The present study suggests that the tested Artemisia species exerted their anticancer effects through the induction of apoptosis via an ER-related pathway.