Abstract
The lateral diffusion coefficient in phosphatidylcholine membranes was determined using pyrene as a fluorescence probe, and the effect of α-, γ- and σ-tocopheryl acetates on the liposomes and the interaction between tocopheryl acetates and cholesterol in the liposomes were studied. α-, γ- and σ-Tocopheryl acetates reduced the diffusion of pyrene in the liposomes of dipalmitoyl, egg yolk and soybean phosphatidylcholines. α-Tocopheryl acetate was the most effective compound among the three tocopheryl acetates to reduce the diffusion coefficient of pyrene, and the degree to reduce the diffusion of pyrene by each tocopheryl acetate correlated well with its vitamin E activity. Tocopheryl acetates and cholesterol independently reduced the diffusion of pyrene in the membranes. The results suggest that tocopherols may physically stabilize biological membranes.
