α-Tocopherol-Induced Hexagonal H_<II> Phase Formation in Egg Yolk Phosphatidylcholine Membranes

概要

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The effect of α-tocopherol and its acetate on the membrane structure of egg yolk phosphaticdylcholine (egg PC) dispersions was investigated using phosphate-31 nuclear magnetic resonance (^<31>P-NMR) and small-angle X-ray diffraction. The incorporation of α-tocopherol into egg PC dispersions induced a change in the ^<31>P-NNR spectrum from a multilamellar bilayer line shape to a hexagonal H_<II> one. The phase transition by α-tocopherol was also confirmed by small-angle X-ray diffraction analysis. The amount of hexagonal H_<II> phase increased with increase in concentration of α-tocopherol. Egg PC dispersions containing a molar ration of 0.8 of α-tocopherol gave a ^<31>P-NMR spectrum of an approximately hexagonal H_<II> type at 37℃. The amount of hexagonal H_<II> phase increased with increasing temperature, indicating that the α-tocopherol-induced phase transitin is thermotropic and that the transition temperature of egg PC membranes from the lamellar to the hexagonal H_<II> phase is lowered by α-tocopherol. The incorporation of α-tocopherol acetate did not induce any phase transition. This fact indicates that the hydroxyl group of α-tocopherol may play an important role in the hexagonal H_<II> phase formation of egg PC dispersions.
社団法人日本薬学会の論文
1990-01-25