Methods
(a) the MTT assay and (b) the trypan blue dye exclusion test. Whereas macrophages were more sensitive to PIC (LC(50 trypan) approximately 1.3 muM) and to TPS (LC(50 trypan) approximately 4.0 microM and LC(50 MTT) approximately 8.3 microM) than to RES (LC(50 trypan) approximately 8.9 microM and LC(50 MTT) approximately 29.0 microM), they were relatively resistant to TSO (LC(50 trypan) approximately 61.0 microM and LC(50 MTT) > 100 microM) and to TS (LC(50 trypan) > or = 5.0 microM and LC(50 MTT) > or = 5.0 microM). The ability of selected stilbenes (RES, TPS and PIC) to exhibit growth inhibitory effects was also examined. Although RES and TPS were observed to inhibit cell proliferation in macrophages (IC(50) < or = 25 microM), these cells were resistant to growth inhibition by PIC (IC(50) > or = 50 microM). The data obtained in the present analysis demonstrate that substituted stilbene compounds such as RES have the capacity to exhibit cytotoxic and anti-proliferative activities in macrophages.