Comparison of structures, physicochemical properties and in vitro bioactivity between ferulic acid-β-cyclodextrin conjugate and the corresponding inclusion complex

In this study, ferulic acid (FA) was covalently bound to one of the primary hydroxyls of beta-cyclodextrin (beta-CD) via an ester linkage to improve its stability and biological activity. Experiments using UV, FTIR, FS, NMR, MS and FE-SEM were performed to characterize the structure of the FA-beta-CD conjugate. Physicochemical properties such as solubility, crystallinity, thermal stability and photo-stability of the conjugate were also investigated, and the results revealed that the conjugate was in an amorphous form with improved thermal stability and photostability compared with the FA/beta-CD inclusion complex. Furthermore, in vitro cytotoxicity of the FA-beta-CD conjugate against HepG2 cell was enhanced with effective growth inhibition. Taken together, the present study indicates that the FA-beta-CD conjugate might be a novel and potential functional composition for application in food and medicine.