Effect of Korean Red Ginseng Extract on Cell Death Responses in Peroxynitrite-Treated Keratinocytes

Korean red ginseng (KRG) has been used worldwide as a traditional medicine for the treatment of various diseases, including cancer. In this study, we determined the effect of KRG on the responses of HaCaT cells to peroxynitrite (ONOO-). Cells treated with ONOO- (2 mM) prior to incubation with control medium for 12 hours displayed reduced viability, as determined using the 3[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (viability about 48% of that of non-treated control cells). When KRG was added to the post-incubation medium, the negative effects of ONOO- on cell viability were significantly reduced. Reverse transcription-polymerase chain reaction analysis indicated that KRG alone did not significantly alter p53 or growth arrest and DNA damage (GADD)45 mRNA levels. However, the addition of KRG to the post-incubation medium significantly and dose-dependently reduced levels of p53 and GADD45 mRNA in ONOO--treated cells. Western blot analyses revealed that incubation with KRG decreased p53 and GADD45 protein levels in ONOO--treated cells, relative to those in cells incubated with control medium. Collectively, these results suggest that Korean red ginseng extract protects cells against ONOO--induced genotoxicity by increasing cell viability through modulating the expression of p53 signaling intermediates.