Effects of GS on DOX-induced apoptosis using caspase-3 activity assay in H9C2 cells. Subconfluent H9C2 cells were treated with DOX and co-treated with different concentrations of GS for 24 h, and caspase-3 activity was measured using colorimetry. The results are expressed as mean±S.E. from 3 independent experiments. **P < 0.01 indicates a significant difference from DOX treatment. ##P < 0.01 indicates a significant difference from the control (GS 0 μM and DOX 0 μM).