Solubilization, stability and antioxidant activity of curcumin in a novel surfactant-free microemulsion system

Abstract

A novel surfactant-free microemulsion (SFME) containing ethyl benzoate, ethanol and water was constructed, and was divided into three subregions O/W (I), B.C. (III) and W/O (II) according to the conductivity curves. The morphologies of the SFME were observed by a transmission electron microscope (TEM). The dynamic light scattering (DLS), Fluorescence spectroscopy (FS), Fourier-transform infrared spectroscopy (FT-IR) and UV–visible spectroscopy were used to investigate the ordered microstructures, micropolarity, solubilization microenvironment and solubilization performance of the SFME, respectively. The solubilization of curcumin in the O/W SFME was investigated, and the solubilization amount of curcumin was measured to be 17.54 mg/ml. The experiments on the in vitro stability and antioxidant capacity show that when curcumin is embedded in the O/W SFME, its storage stability, light stability, thermal stability and antioxidant activity are significantly improved. This research is of great significance for the practical application of curcumin and other biomolecules.