Characterization and antioxidant activity of the complexes of tertiary butylhydroquinone with β-cyclodextrin and its derivatives

Tertiary butylhydroquinone (TBHQ) is a water-insoluble antioxidant. In this study, three cyclodextrin inclusion complexes were prepared to improve the water solubility of TBHQ and expand its range of application. Analysis of phase solubility indicated that TBHQ can form 1:1 inclusion complex with hydroxypropyl-beta-cyclodextrin (HP-β-CD) and dimethyl-beta-cyclodextrin (DM-β-CD) and 1:2 inclusion complex with beta-cyclodextrin (β-CD). The possible inclusion configuration between TBHQ and CDs was determined through FT-IR, PXRD, DSC, NMR, and SEM analyses. Results were validated by theoretical study of AutoDock molecular docking. The scavenging effects of the inclusion complexes were not effective on DPPH radical but higher on hydroxyl, superoxide and ABTS+ radicals than that of TBHQ monomer. Moreover, the water solubility of TBHQ increased after complexation with HP-β-CD and DM-β-CD. The stability of TBHQ is related to the type of storage materials used, and the stability can be improved by complexation with CDs.