Figure 3.

Antioxidant effect of phenolic compounds in HEL cells and HUVEC exposed to oxidative stress generated by 50 μM H₂O₂. Cells were preincubated with different compounds (5 or 10 μM for HEL cells, (a); 10 μM for HUVEC, (b)) for 20 hours, treated with H₂O₂ for 30 min, then ROS levels were measured by means of H₂DCFDA assay as described in Section 2. Results are expressed as means ± SD of three independent experiments, each performed in octuplicate. **P < 0.005, significantly different from control cells; ***P < 0.0005, significantly different from control cells.