A combined calorimetric, spectroscopic and molecular dynamic simulation study on the inclusion complexation of (E)-piceatannol with hydroxypropyl-β-cyclodextrin in various alcohol + water cosolvents

Publication date: Available online 17 January 2019Source: The Journal of Chemical ThermodynamicsAuthor(s): Chang Cai, Min Liu, Hui Yan, Yanna Zhao, Yabo Shi, Qingying Guo, Wenxin Pei, Jun Han, Zhengping WangAbstract(E)-Piceatannol, a naturally occurring polyphenol, has gained increasing interests in pharmaceutical and food industries due to the health-promoting effects. However, the application of (E)-piceatannol is severely limited by its low solubility and poor bioavailability. Cosolvation and complexation are two effective methods to increase the solubility of insoluble active compounds. The effect of alcohol + water cosolvents on the inclusion complexation of (E)-piceatannol with hydroxypropyl-β-cyclodextrin (HP-β-CD) was investigated using isothermal titration calorimetry, fluorescence spectroscopy and molecular dynamics simulation. The stoichiometry and thermodynamic parameters for the complexation process were obtained. The results showed a 1:1 stoichiometry between (E)-piceatannol and HP-β-CD. The complexation constants decreased with the increase of the alcohol concentration and the alkyl chain length, but increased with the increasing number of hydroxyl groups of the alcohols. The main driving forces for the inclusion process were obtained from the enthalpy and entropy changes. The effect of temperature on the inclusion complexation was discussed in terms of the heat capacity change calculated from the temperature dependence of enthalpy change. The...
Source: The Journal of Chemical Thermodynamics - Category: Chemistry Source Type: research
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