Interaction between sodium ascorbate and dopamine

The interaction between sodium ascorbate and dopamine was investigated by t hree different parameters: radical intensity, prooxidant action, and cytoto xicity induction. Sodium ascorbate and dopamine produced the doublet and qu artet ESR signals under alkaline conditions (pH 8.0-9.5), respectively. Add ition of increasing concentrations of sodium ascorbate completely scavenged the dopamine radical and replaced the latter with its own radical. Similar ly, dopamine slightly, but significantly reduced the radical intensity of s odium ascorbate. These two compounds stimulated the methionine oxidation an d hydrogen peroxide generation in culture medium, but in combination, their stimulation activities were weakened. Both of these two compounds dose-dep endently reduced the viable cell number of human oral squamous carcinoma HS C-4 cells, and their cytotoxic activity was significantly reduced by catala se. When these two compounds were mixed together before adding to HSC-4 cel ls, both of their cytotoxic activities were diminished. The present study d emonstrates the interaction between sodium ascorbate and dopamine, which mi ght modify their biological activities and generation of nerve disorders su ch as Parkinson's disease. (C) 1998 Elsevier Science Inc.