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

• RA showed an aggregation behavior (c.m.c. of 35 μM at pH 8 and 25 °C) which could be modified by the presence of CD.
• The RA/CD complexes presented a 1:1 stoichiometry and the KF was dependent on pH, temperature and type of CD.
• The pKa calculated for RA was 4.31.
• Molecular docking provided further insights about the interactions in the complexes.

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 μM at pH 8 and 25 °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 HPβCD was the best for encapsulating RA. The pKa determined for RA was 4.31. The KF showed different behavior below and above 25 °C due to changes in the stoichiometry. Finally, molecular docking calculations provided further insights into how the different interactions influence the complexation constant.