Effects of inclusion of chrysin in cucurbit[8]uril on its stability, solubility and antioxidant potential

The host-guest interaction between cucurbit[8]uril(Q[8]) and chrysin(CHR) has been studied by means of 1H NMR, mass spectrometry(MS), differential thermal analysis(DTA), and UV-Vis spectrophotometry. The results show that CHR forms a 1:1 inclusion complex with Q[8], with a binding constant of CHR with Q[8] by UV absorption being 5.4×106. Phase solubility experiments show a 5.13-fold increase in the solubility of CHR through interaction with Q[8]{c(Q[8])=10‒4 mol/L}. A study of the evolution of UV absorption spectra with time shows that Q[8] significantly increases the stability of CHR. The antioxidant activity of CHR-Q[8] has been tested by the ABTS method. The CHR-Q[8] inclusion complex shows a better scavenging effect towards the ABTS radical than CHR, with respective IC50 values of 1.05×10–6 and 3.07×10–6 mol/L. In vitro release studies have shown that CHR-Q[8] has a sustained release effect.