Onuki Yoshinori, Morishita Mariko, Chiba Yoshiyuki, Tokiwa Shinji, Takayama Kozo
Department of Pharmaceutics, Hoshi University, Ebara, Tokyo, Japan.
Chem Pharm Bull (Tokyo). 2006 Jan;54(1):68-71. doi: 10.1248/cpb.54.68.
We investigated the effect of fatty acids such as stearic acid (SA, 18:0), oleic acid (OA, 18:1), eicosapentaenoic acid (EPA, 20:5), and docosahexaenoic acid (DHA, 22:6) on a dipalmitoylphosphatidylcholine (DPPC) bilayer by determining the phase transition temperature, fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH), and detergent insolubility. Treatment with unsaturated fatty acid broadened and shifted the phase transitions of the DPPC bilayer to a lower temperature. The phase transition temperature and the value of fluorescence anisotropy of DPH at 37 degrees C decreased progressively with increasing treatment amounts of unsaturated fatty acid. A large amount of the DPPC bilayer treated with unsaturated fatty acid was dissolved in Triton X-100, obtaining a low level of detergent insolubility. These modifications of the bilayer physical properties were most pronounced with DHA and EPA treatment. These data show that unsaturated fatty acids, particularly DHA and EPA, induce a marked change in the lipid bilayer structure. The composition of fatty acids in the DPPC bilayer was similar after treatment with various unsaturated fatty acids, suggesting that the different actions of unsaturated fatty acids are attributed to change in the molecular structure (e.g., kinked conformation by double bonds). We further explored the change in physical properties induced by fatty acids dispersed in a water-in-oil-in-water multiple emulsion and found that unsaturated fatty acids acted efficiently on the DPPC bilayer, even when incorporated in emulsion form.
我们通过测定相变温度、1,6 - 二苯基 - 1,3,5 - 己三烯（DPH）的荧光各向异性以及去污剂不溶性，研究了硬脂酸（SA，18:0）、油酸（OA，18:1）、二十碳五烯酸（EPA，20:5）和二十二碳六烯酸（DHA，22:6）等脂肪酸对二棕榈酰磷脂酰胆碱（DPPC）双层膜的影响。用不饱和脂肪酸处理会使DPPC双层膜的相变变宽并向更低温度偏移。随着不饱和脂肪酸处理量的增加，37℃时DPPC双层膜的相变温度和DPH荧光各向异性值逐渐降低。用不饱和脂肪酸处理的大量DPPC双层膜可溶于Triton X - 100，导致去污剂不溶性水平较低。这些双层膜物理性质的改变在用DHA和EPA处理时最为明显。这些数据表明，不饱和脂肪酸，尤其是DHA和EPA，会引起脂质双层结构的显著变化。用各种不饱和脂肪酸处理后，DPPC双层膜中的脂肪酸组成相似，这表明不饱和脂肪酸的不同作用归因于分子结构的变化（例如，双键导致的扭结构象）。我们进一步探究了分散在水包油包水多重乳液中的脂肪酸所引起的物理性质变化，发现即使以乳液形式掺入，不饱和脂肪酸也能有效地作用于DPPC双层膜。
