Rosmarinic Acid (RA) is a natural phenolic compound found in Lamiaceae herbs and well known by its antioxidant and anti-inflammatory properties. RA has
been also investigated as a chemopreventive agent; however, its ability to prevent
or suppress DNA damage has not been investigated before in human cell lines. In the
present study the effects of RA on DNA repair kinetics was investigated using the
normal human fibroblast cell line (GM07492-A) submitted to in vitro genotoxic stress with H2O2. Cytotoxicity assay in a concentration range from 2–256µM was performed using the
XTT method. Alkaline version of comet assay was employed to assess the DNA repair
kinetics with 2, 4, 8µM of RA associated with hydrogen peroxide (H2O2) at 50µM. Cells were harvested immediately after DNA damage induction with H2O2 (T0), and 1h (T1), 2h (T2), 4h (T3) and 6h (T2) after recovery with RA. Results demonstrated
that RA was not cytotoxic in all tested concentrations. Comet assay revealed that
RA exhibits antigenotoxic activity by the improvement of the DNA repair kinetics in
H2O2 treated cells. The reduction in the extension of DNA damage was not concentration
dependent, but cells submitted RA treatment were completely recovered at T3. These
results demonstrate that RA can protect DNA against oxidative injury, representing
a potent chemoprotective agent in normal cells. The next step of this study includes
the elucidation of the molecular signaling pathways involved in the DNA repair process
modulated by RA treatment in conditions of genotoxic stress.