Enhanced solubility of bisdemethoxycurcumin by interaction with Tween surfactants: Spectroscopic and coarse-grained molecular dynamics simulation studies

The oral bioavailability of bisdemethoxycurcumin, one of the main active compounds of curcuminoids, can be improved by the encapsulation of surfactant micelles. The interaction of bisdemethoxycurcumin with Tween 20 and Tween 60 micelles was investigated by spectroscopic techniques and molecular dynamics simulation. The binding parameters were obtained from temperature-dependent fluorescence and absorption spectra. The main driving forces were inferred from the enthalpic and entropic contributions. The binding site and surrounding microenvironment of bisdemethoxycurcumin in Tween micelles were evaluated. Coarse-grained molecular dynamics simulations confirmed the binding of bisdemethoxycurcumin with Tween micelles from the microscopic perspective. The influence of different alkyl chains of Tween 20 and Tween 60 on their interaction with bisdemethoxycurcumin and their solubilization capability toward bisdemethoxycurcumin was discussed. These results suggested that Tween 20 and Tween 60, especially Tween 60, can be used as carriers for encapsulating bisdemethoxycurcumin to increase its aqueous solubility.