The caspase activities of cells treated with phytoestrogens. Caspase 8 and caspase 9 activities were measured in treated cells at the times indicated. Treatments were: vehicle control (Con), 10-7 M trans-resveratrol (Res), 10-7 M genistein (Gen), 10-7 M Daidzein (Dai), 10-8 M coumesterol (Cou), or 10-9 M E2. We measured (A) caspase 8 or (B) caspase 9 (n = 8). * = p < 0.05 compared to control. # = p < 0.05 compared between 2 and 24 hr. (C) To demonstrate the specificity of these actions by phytoestrogens on caspase 8, caspase 8 activity was attenuated by 5 μM caspase 8 inhibitor Ac-IETD-CHO (Con+Inh) measured at 24 hours, (n = 16). * = p < 0.05 compared to control. The caspase activity is expressed as change in fluorescence intensity (excitation wavelength of 400 nm and an emission wavelength of 505 nm) during an hr for 2500 cells.