Fig. 6.

Curcumin analog A2 increased the level of NADH/NADPH oxidase-derived reactive oxygen species (ROS). a Flow cytometric analysis of the intracellular ROS levels. Human umbilical vein endothelial cells (HUVECs) were treated with dimethyl sulfoxide (DMSO) or curcumin analog A2 (20 μM) for 3 h, then the cells were loaded with 10 µM DCFH-DA for 20 min. b Flow cytometric analysis of the mitochondrial ROS levels. HUVECs were treated with DMSO or curcumin analog A2 (20 μM) for 3 h, then the cells were loaded with 5 µM MitoSOX® Red for 20 min. c Fluorescence photographs of JC-1 staining in HUVECs treated with DMSO or curcumin analog A2 (20 μM) for 6 h. CCCP-treated cells were used as positive controls. Scale bar: 10 μm. d Flow cytometric analysis of JC-1 staining in HUVECs treated with DMSO or curcumin analog A2 (20 μM) for 6 h. CCCP-treated cells were used as positive controls. e Flow cytometric analysis of the intracellular ROS levels. HUVECs were treated with DMSO or curcumin analog A2 (20 μM) in the presence or absence of DPI for 3 h, then the cells were loaded with 10 µM DCFH-DA for 20 min