Interaction between morin and sodium dodecyl sulfate (SDS) micelles.

Electronic absorption spectra, fluorescence emission spectra, ATR-FTIR spectra, cyclic voltammetric measurements, and ab initio quantum calculation are used to study the properties of morin in SDS micelles of different microstructures and microenvironments and to gain the information about the binding of morin with the SDS micelles. Morin can be located in the SDS micelles with its phenyl group (deviating by 38.98 degrees from the planarity), which leads to the increase of the planarity and the extension of pi conjugation of the whole molecule. The embedment of two hydroxyl groups on the phenyl into a more hydrophobic microenvironment makes the oxidation peak of morin move to a higher potential with a decreased peak current. The binding constant (K) and the distribution coefficient (P) of morin in the spherical SDS micelle are larger than those in the rodlike SDS micelle. The binding of morin with SDS micelle is a spontaneous (DeltaG < 0) and exothermic process (DeltaH < 0), and the hydrophobic force is the main driving force for its solubilization.