Effects of Pro-Arg, a novel dipeptide derived from protamine hydrolysate on H2O2-induced oxidative stress in human diploid fibroblasts.

Oxidative stress plays an important role in tissue damage associated with many different chronic degenerative diseases, such as cancer and cardiovascular disorders. In our previous study, a novel dipeptide Pro-Arg derived from protamine hydrolysates was found to possess significant antioxidative activity in vitro. In this study, we compared the antioxidant capabilities of purified and synthesized dipeptide (Pro-Arg) and found both of them had very strong hydroxyl-radical scavenging activity in vitro, even at a very low concentration. The protective effect of the dipeptide against oxidative stress was evaluated using H2O2-induced oxidative stress of human diploid fibroblasts MRC-5 cell model. Our results showed the dipeptide attenuated H2O2-induced cellular oxidative damage, and normalized S phase arrest of MRC-5 cells exposed to H2O2. Our findings demonstrate that Pro-Arg can protect against oxidative stress/damage and H2O2-induced human diploid fibroblasts cell death.