Figure 5 (a) Analysis of ROS formation using DCFH-DA on H9c2 cells treated with ARB and ISO. (i) Control. (ii) ISO (25 μM) yellow arrow indicates increased green fluorescence and increased ROS formation. (iii) ARB (40 μM). (iv) ARB 40 μM + ISO. *Significant compared to control (P < 0.05). (b) Cells-depicted fluorescence intensity was detected by spectrofluorometer. **Significant compared to ISO-administered cells. *Significant compared to normal H9c2 cells (P < 0.05). ARB, arbutin; DCFH-DA, dichlorofluorescein diacetate; ISO, isoproterenol hydrochloride; ROS, reactive oxygen species.