薄层色谱法测定大黄类药物与环糊精的包结常数  

Determination of Formation Constants for the Inclusion Complexes Between Emodin, Aloe-emodin and Cyclodextrins by Thin Layer Chromatography

作　　者：王小萍[1] 马麦霞[1] 双少敏[1] 张勇[1] 潘景浩[1] 

机构地区：[1]山西大学化学系,太原030006

出　　处：《分析化学》2002年第1期38-41,共4页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金(No.20045001);山西省自然科学基金(No.981012)资助项目

摘　　要：以环糊精的水溶液为流动相，聚酰胺薄膜为固定相，用反相薄层色谱法研究了大黄有效成份大黄素、芦荟大黄素与环糊精的包结作用，测定了包结常数。环糊精对大黄类药物有明显的增溶作用，且环糊精与大黄类药物的包结作用符合熵焓补偿规律，补偿温度为２９６．５Ｋ；通过熵焓补偿规律得出，大黄类药物与环糊精的包结过程中环糊精分子结构发生了较大的变化，同时经历了适中的去溶剂化步骤。The interaction between emodin, aloe-emodin and six cyclodextrins (CDs) has been studied by reversed-phase thin-layer chromatography. The NH3 . H2O-NH4Cl buffer containing various CDs ( pH = 9.7, 20 T) and polyamide plate were selected respectively as mobile and stationary phases. CDs except for alpha-CD and carboxymethyl-beta-CD can form inclusion complexes with these two drugs. Furthermore, the comparison of inclusion capacity of different CDs indicates that for the ionic cyclodextrins, the charge interaction plays an important role in the inclusion procedure. The thermodynamic parameters of interaction imply that the inclusion process shows the enthalpy-entropy compensation effect at compensation temperature of 296.5 K. The DeltaH-TDeltaS plot for CDs shows an excellent linear relationship, affording a very large slope (alpha = 0.995) and intercept (TDeltaS(0)(0) = 13.5), which indicates that the enthalpic gain from the inclusion complexation is completely canceled out by the entropic loss from the conformational changes caused upon guest inclusion. The marked influence of CDs on the hydrophobility of emodin and aloe-emodin suggests that this interaction may modify the biological properties of Emodin and Aloe-emodin.

关 键 词：环糊精 大黄素 芦荟大黄素 反相薄层色谱 包结常数 熵焓补偿 中药 包结常数 

分 类 号：O657.7[理学—分析化学]