PHOSPHOLIPIDS INCREASE RADICAL-SCAVENGING ACTIVITY OF VITAMIN E IN A BULK OIL MODEL SYSTEM

摘要

The effect of phospholipids on the radical-scavenging activity of vitamin E in a bulk oil model was studied to clarify the mechanism of their antioxidant synergism. Phospholipids retarded the consumption of vitamin E and elongated the induction period arising from vitamin E in the mixture of methyl linoleate and methyl laurate when exposed to a water-soluble radical initiator. However, they accelerated the consumption of vitamin E in methyl laurate alone. On the other hand, phospholipids little affected the consumption of vitamin E when lipid peroxidation was initiated by a lipid-soluble radical initiator. These results implied that phospholipids enhanced the accessibility of vitamin E toward the chain-initiating radicals in an aqueous microenvironment, resulting in the interruption of chain initiation. Phospholipids could act as neither the free radical scavengers nor the regenerators for vitamin E in this model system. Thus, it is concluded that the enhanced effect of phospholipids for vitamin E in bulk oil originated from the elevation of its radical-scavenging activity.