DSC和同步辐射宽角XRD法研究丹皮酚在脂质体疏水尾链区的包封位置及对膜流动性的影响

Encapsulating Location of Paeonol in Hydrophobic Tail Chain of Liposomes and Its Effect on the Membrane Fluidity: Study with DSC and Synchrotron Wide-angle XRD Methods

目的:研究丹皮酚在脂质体疏水尾链区的包封位置及对膜流动性的影响,进而探讨其抗氧化作用机制。方法:薄膜分散法制备丹皮酚脂质体,采用差示扫描量热法(DSC)研究丹皮酚对脂质体膜主相变的影响,进而探讨丹皮酚在脂质体疏水尾链的包封位置,采用同步辐射宽角X光衍射法(XRD)研究丹皮酚对液晶态的脂质体膜疏水尾链间距的影响,进而探讨其对膜流动性的影响及与抗氧化作用机制的关联。结果:DSC结果表明,随着丹皮酚浓度的增大,脂质体的主相变温度逐渐降低,半峰宽逐渐增大,同步辐射宽角X光衍射结果表明与液晶态的空白脂质体相比,丹皮酚的包封增大了磷脂分子疏水尾链之间的距离。结论:丹皮酚分子主要作用在磷脂分子疏水尾链的C1~C9的位置;丹皮酚的包封可以增加液晶态膜尾链的无序度,从而提高膜的流动性,这是其发挥抗氧化作用可能的作用机制。

Objective ： To study the encapsulating location of paeonol in hydrophobic tail chain of liposomes and its effect on membrane fluidity to disclose the mechanism of the antioxidant effect of paeonol. Methods ： Lipo- somes were prepared by film dispersion method. Differential scanning calorimetry（DSC） was employed to in- vestigate the effect of paeonol on the main transition of liposomes and to disclose the encapsulating location of paeonol in liposomes. Synchrotron wide -angle X -ray diffraction（XRD） technique was employed to investi- gate the effect of paeonol on the distance between hydrophobic tail chain and its effect on the membrane fluidi- ty of liposomes existing as liquid - crystalline phase. Furthermore, the relationship between XRD results and the mechanism of the antioxidant effect of paeonol was investigated. Results ： The DSC results showed that the temperature of main transition decreases and the half - height width of DSC peaks increased with increased concentration of paeonol. The wide - angle X - ray diffraction results showed that the distance between hydro- phobic chains of phospholipid molecules of paeonol encapsulated liposomes was larger than that of blank lipo- some. Conclusion： The location site of paeonol at the tail chains of DPPC was C1 ~ C9. The incorporation of paeonol into liposomes can increase the disorder of the tail chains of DPPC and improve the fluidity of the membrane, which may be one of the mechanisms of the antioxidant effect of paeonol.