白藜芦醇苷与环糊精在水溶液中包合作用的研究

Cyclodextrins Complexation of Polydatin in Aqueous Solution

分别研究了β-环糊精(β-CD)、羟丙基-β-环糊精(HP-β-CD)在水溶液中对白藜芦醇苷(PD)的包合作用。采用等摩尔系列法测定包合物的包合比,紫外吸收分光光度法、相溶解度法研究2种环糊精(CDS)在水溶液中对PD的包合作用、增溶作用及包合过程中的热力学参数变化。在水溶液中,PD与2种CDS均存在明显的相互作用。PD的溶解度随着CDS浓度的增加而成线性增加,相溶解图呈AL-型;PD与2种CDS在包合过程的吉布斯自由能变化(ΔG)、焓变(ΔH)和熵变(ΔS)均为负值。PD与2种CDS在水溶液中可自发形成摩尔比1︰1的可溶性包合物,从而增加其溶解度。同时,所有包合过程均为焓驱动过程,为放热反应(ΔH<0),焓减过程(ΔS<0),且适当降低温度将有利于包合过程的进行。

Investigated the inclusion effects of polydatin with β-cyclodextrin （β-CD） and hydroxylpropyl-β-cyclodextrin （HP-β-CD） in aqueous solutions, respectively. The measurements of the inclusion molar ratio of the host to guest molecules were carried out by equimolar series method. The intermolecular reaction between the host and the guest agents, soluble effects of β-CD and HP-β-CD on PD in aqueous solution and the change of thermodynamic parameters in the complexation were determined by UV spectrophotometry and phase solubility method. The significant reactions between the host and the guest molecules in aqueous solution were confirmed. The solubility of PD in aqueous solution is linearly escalated with the increased concentration of β-CD and HP-β-CD, showing a plot of the typical AL-type phase solubility. All three thermodynamic parameters AG, AH and AS in the complexation gave negative values. An 1 ： 1 molar ratio inclusion complex of polydatin with β-CD and HP-β-CD could be formed spontaneously under the experimental temperatures. Furthermore, the complex process is enthalpically driven and exothermic. It is also suggested that appropriate reduction of temperature may be favorable to the complexation.