蟾毒灵对脂质体双分子层结构的影响:31P NMR研究

应用³¹P NMR方法研究了蟾毒灵(BF)对脂质体双分子层结构的影响.研究结果表明对于未经超声波处理的卵磷脂(PC),BF对磷脂双分子层膜具有稳定作用.另一方面,当PC经过超声波处理后,首次观测到纯PC的双分子层膜转变为胶束或微胞,后者的比例随着超声波处理的时间的增加而增加;而BF的存在可加速PC由双分子层结构向胶束相的转变.

THE EFFECT OF BUFALIN ON THE STRUCTURE OF PHOSPHOLIPID LIPOSOME AS STUDIED BY31P NMR SPECTROSCOPY

The egg yolk phosphatidylcholine(PC) liposomes loaded with bufalin(BF) were prepared so as to improve BF's therapeutic effect. The effects of BF on PC model membrane have been examined using the \{\}\ \{31\}P NMR spectroscopy. The results show that the incorporation of BF into PC liposome can stabilize the lipid bilayer structure of PC, with the basal linewidth of the \{\}\ \{31\}P spectrum increasing with increasing the content of BF in liposome. This may be related to the formation of hydrogen bonding between BF and polar headgroup of PC, or insertion of BF into PC by hydrophobic interaction. On the other hand, it was found for the first time that after exposure to ultrasonic waves, pure PC shows an additional narrow peak at the isotropic chemical shift (i.e., about 0.23ppm) in its \{\}\ \{31\}P spectrum which corresponds to the mobile lipidic particles, e.g., micelles or small resicles, and furthermore, the addition of BF can significantly trigger such a transition from the phospholipid bilaryer to the micellar phase. This could be explained by the insertion of BF into the micellar phase or the formation of mobile BF PC complexes. These studies demonstrate that the presence of BF has two sided effect on the membrane structure of PC, depending on the preparation conditions of the liposome. Therefore, on preparing the BF loaded liposome, partial attention should be paid to the potential influence of the preparation conditions on the structure and then physiochemical properties of the liposome, in addition to the effects of the medicine itself.