Neuroprotective effect of raspberry extract by inhibiting peroxynitrite-induced DNA damage and hydroxyl radical formation

Raspberry extract has recently been reported to show neuroprotective capacity in a neurodegeneration cell model. However, the mechanism underlying raspberry extract-mediated neuroprotection is unknown. Because peroxynitrite is involved in the pathogenesis of neurodegenerative diseases via its cytotoxic effects, this study was undertaken to investigate whether the neuroprotective effect of raspberry extract is associated with inhibition of peroxynitrite-induced DNA damage, a critical event leading to peroxynitrite-mediated cytotoxicity. Our results showed that peroxynitrite can cause DNA damage in φX-174 plasmid DNA and rat primary astrocytes. The presence of raspberry extract (50-100 μg/ml) was found to significantly inhibit peroxynitrite-induced DNA cleavage. EPR spectroscopy demonstrated that the formation of DMPO-hydroxyl radical adduct (DMPO-OH) from peroxynitrite, and that raspberry extract potently diminished the adduct signal in a concentration‐dependent manner. Taken together, these results demonstrate for the first time that raspberry extract can protect against peroxynitrite-mediated DNA damage and hydroxyl radical formation.

► Peroxynitrite can cause DNA damage in φX-174 plasmid DNA and rat primary astrocytes. ► Raspberry extract inhibits peroxynitrite-induced DNA damage and cytotoxicity. ► Raspberry extract significantly scavenges hydroxyl radicals from peroxynitrite.