Physicochemical, thermal and computational study of the encapsulation of rumenic acid by natural and modified cyclodextrins

In this work the aggregation behavior of Rumenic acid (RA) is presented for the first time. The results point to a c.m.c. of 35 mu M at pH 8 and 25 degrees C. This behavior can be modified by introducing CDs into the system to encapsulate the RA. The encapsulation process presented a 1:1 stoichiometry in all the cases studied but the complexation constants were strongly dependent on the type of CDs used, the pH and temperature. Firstly, the effect of the type of CD on the encapsulation process was studied. Among the natural and modified CDs analyzed HP beta CD was the best for encapsulating RA. The pK(a) determined for RA was 4.31. The K-F showed different behavior below and above 25 degrees C due to changes in the stoichiometry. Finally, molecular docking calculations provided further insights into how the different interactions influence the complexation constant. (C) 2016 Elsevier Ltd. All rights reserved.