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 absorp- tion being 5.4 × 106. Phase solubility experiments show a 5.13-fold increase in the solubility of CHR through interac- tion with Q[8] {c（Q[8]）=10-4 real/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 me- thod. 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 effcct.