KINETIC EVALUATION OF LIPOPHILIC INHIBITORS OF LIPID-PEROXIDATION IN DLPC LIPOSOMES

The authors have developed a kinetic method that allows one to obtain relative reactivity constants for lipophilic antioxidants in free radi cal systems. Two experimental model systems were developed: (a) a meth anolic solution using AMVN as the free radical initiator and linoleic acid as the substrate, and (b) a multilamellar vesicle system composed of dilinoleoyl-phosphatidylcholine and AAPH as the substrate and the initiator, respectively. The use of these two systems allows researche rs not only to determine the intrinsic reactivity of a potential antio xidant, but also to evaluate its potency in a membranous system where the contribution of the physical properties of the antioxidant to the inhibition of lipid peroxidation is important. These results show that all antioxidants tested acted in these systems as free radical scaven gers, and they validate the synergism between intrinsic scavenging abi lity and membrane affinity and/or membrane modifying physical properti es in the inhibition of lipid peroxidation.