ANTIOXIDANT ACTIVITY OF LIPOPHILIC VITAMIN-C DERIVATIVE IN DIPALMITOYL PHOSPHATIDYLCHOLINE VESICLES - A STOPPED-FLOW ESR KINETIC-STUDY

The antioxidant reactivity of the lipophilic derivative of vitamin C, i.e., ascorbyl-6-palmitate (VC-16) was remarkably enhanced in dipalmit oyl phosphatidylcholine (DPPC) vesicles. The mte enhancement is tentat ively explained by a vesicle fusion mechanism and subsequent lateral d iffusion of reactants within the vesicle. The reduction of nitroxides incorporated into the vesicle by VCs was employed to examine the distr ibution of the nitroxide inside and outside the vesicle as well as the dynamic behaviour of the inside-outside transition (flip-flop).