Induction of MKN-28 cell death by GA and Doc. After 48 h incubation with GA (0.25 μM) (b), Doc (0.625 μM) (c) or GA (0.25 μM) plus Doc (0.625 μM) (d), morphological changes in MKN-28 cells were observed under light microscopy. Cells without any treatments were used as controls (a). (e) Annexin-V and PI double staining for cells from panel d). Samples were visualized under a fluorescent microscope. Annexin-V-labeled cells with green fluorescence were recognized as early apoptotic cells; annexin-V and PI double-labeled cells with orange fluorescence were recognized as late apoptotic or necrotic cells.