The number of antioxidants that have been claimed to be potentially used in pharmaceutical or cosmetic sectors is very large. For example, thousands of phenolic molecules have already been structurally characterized and many of them have been evaluated in vitro for their radical scavenging or metal chelating properties. In front of this multitude of compounds, there is a need in evaluating their activity in cells and also a great interest in identifying specific molecules with mitochondria targeting activity to combat oxidative stress situations. In that context, we have screened several natural phenolic compounds or synthesized derivatives for their ability to scavenge ROS in fibroblast cells. For this, ROS inhibiting action was evaluated at short and long times. Our results showed that some molecules were active rapidly but lose their activity for longer term, while others tend to be more active at longer period. These results suggest that more detailed kinetics of ROS inhibiting action are needed for the most active compounds and that combination of fast and slow acting molecules are promising strategies to identify synergistic antioxidant combinations. Finally, the most promising candidates were evaluated for their mitochondria targeting activity, and among them, sinapine extracted from canola meal.