Cytotoxic effects of eugenol on breast cancer cells. (A) Exponentially growing cells were cultured in 96 well plates and treated with the indicated concentrations of eugenol for 24 hrs. Cell death was analyzed using the WST-1 assay. The arrows indicate the LC50 for each cell line. Error bars represent means ± S.D. (B) Cells were either sham-treated (DMSO) or challenged with the indicated concentrations of eugenol for 72 hrs, and then cell death was assessed by PI/annexinV/flow cytometery. (C) Histograms presenting the proportions of induced apoptosis in the various cell lines. Data are presented as means ± S.D.