Sterically hindered phenol-dextran conjugates: radical scavenging activityin water and water-organic media

The radical scavenging activity investigation of sterically hindered phenol s-dextran conjugates was carried out in water and water-dioxane mixtures wi th use of sodium salt of 2,2-diphenyl-1-picryl-hydrazyl sulfonic acid (DPPH -SO3Na). The suggestion was made that the reaction mechanism includes the o ne-electron transition stage. It was found that the reaction rate constants of DPPH-SO3Na with the conjugates are higher than the ones with low-molecu lar weight model. One of possible reasons for obtained data could be the fa ct that dextran hydration shell stabilizes the cation-radical intermediate in case of conjugates better than bulk water. (C) 2000 Elsevier Science Ltd . All rights reserved.