Peroxynitrite Scavenging Activity and its Mechanism of Cheonga-hwan

청아환의 Peroxynitrite 제거 활성 및 기전

Objectives: Peroxynitrite ($ONOO^{-}$), formed from the reaction of superoxide <${\cdot}O_2^{-}$) and nitric oxide (NO), is a cytotoxic species that can oxidize several cellular components such as proteins, lipids and DNA. It has been implicated in diseases such as aging process, Alzheimer's disease, rheumatoid arthritis, cancer and arteriosclerosis. Due to the lack of endogenous enzymes responsible for $ONOO^{-}$ inactivation, developing a specific $ONOO^{-}$ scavenger is of considerable importance. The aim of this study was to evaluate $ONOO^{-}$ scavenging activity and its mechanism in Cheonga-hwan (CAH). Methods: The $ONOO^{-}$ scavenging activity in CAH was assayed by measuring oxidized dihydrorhodamine 123 (DHR 123) by fluorescence. The scavenging efficacy was expressed as $IC_{50}$, showing the concentration of each sample required to cause 50% inhibition of DHR 123 oxidation. In a separate study, the protective effect of CAR on $ONOO^{-}$-induced nitration of bovine serum albumin (BSA) was investigated using immunoassay with a monoclonal anti-nitrotyrosine antibody, and a horseradish peroxidase-conjugated anti-mouse secondary antibody from sheep. Results: CAH showed potent scavenging activities of $ONOO^{-}$, NO and ${\cdot}O_2^{-}$. The data demonstrated that CAH led to decreased $ONOO^{-}$-mediated nitration of tyrosine through electron donation. CAH showed significant inhibition on nitration of bovine serum albumin by $ONOO^{-}$ in a dose-dependent manner. Conclusions: CAH can be developed as an effective peroxynitrite scavenger for the prevention of the $ONOO^{-}$ involved diseases.