[关键词]
[摘要]
目的 采用高效液相色谱方法测定不同采收期细柱五加叶中五加苷元的量,研究其变化趋势。方法 采用RP-HPLC法测定不同采收期(3~12月份)细柱五加叶中的五加苷元,色谱柱为AT.lichrom ODS-C18柱(250 mm×4.6 mm,5 μm),以乙腈-水-醋酸(60∶40∶0.1)为流动相,柱温25 ℃,体积流量1.0 mL/min,检测波长214 nm,进样量10 μL。结果 细柱五加叶中的五加苷元在秋季时量最高,春季次之,夏季最低。五加苷元量随季节变化明显,10月份采摘其五加苷元量最高。结论 建立稳定性好、准确性高,适用于细柱五加叶中五加苷元的定量分析方法,并可用于分析不同采集期细柱五加叶中的五加苷元动态变化。
[Key word]
[Abstract]
Objective To understand the mechanism on membrane permeability of flavonoid aglycones substituted with different hydroxyl positions and numbers on B ring, and to observe the correlation between molecular dynamic (MD) simulation and experimental results. Methods MD simulation was performed with GROMACS software package. Using accelerated MD simulation, the transmembrane behaviors of five flavonoid aglycones were simulated from nine different initial positions of bilayer lipid. The energy barrier, orientation, hydrogen bonding, and interaction during the transmembrane process were calculated from recorded trajectories. Results The results of MD simulation had a good correlation with the reported experimental data of Caco-2 (r = ?0.786 2). According to our results, the lower energy barrier was for molecules to penetrate the membrane of dipalmitoyl phosphatidylcholine (DPPC), the higher permeability they would get during the process of transmembrane. Electrostatic interaction played much more significant roles in transmembrane than Van der Waals interaction did. The stronger H-bond between molecule and membrane, the longer the molecule stayed in membrane. Hydroxyl-substitution at 2′ position on B ring of flavonoid aglycones could increase the ability of forming H-bond. Hydroxyl-substitution at 3′ or 5′ had appropriate electrostatic repulsion with polar layer which was in favor of transmembrane. Conclusion The hydroxyl-substitution on B ring of flavonoid aglycones affects the indexes of H-bonds, orientation, electrostatic interaction, and energy barrier during transmembrane. The energy barrier of theoretical simulation is a suitable indicator for predicting the transmembrane absorption of flavonoids.
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[基金项目]
湖南省自然科学基金重点项目(11JJ2042);湖南中医药大学“十二五”校级重点学科“药物分析学”建设项目资助;中南大学研究生学位论文创新基金资助(2011ssxt080)