Xanthine Oxidase Inhibitory Activity and Thermostability of Cinnamaldehyde-Chemotype Leaf Oil of Cinnamomum osmophloeum Microencapsulated with β-Cyclodextrin

The xanthine oxidase inhibitory activity and thermostability of Cinnamomum osmophloeum leaf oil microencapsulated with β-cyclodextrin were evaluated in this study. The yield of leaf oil microcapsules was 86.3% using the optimal reaction conditions at the leaf oil to β-cyclodextrin ratio of 15:85 and ethanol to water ratio ranging from 1:3 to 1:5. Based on the FTIR analysis, the characteristic absorption bands of major constituent, trans-cinnamaldehyde, were confirmed in the spectra of leaf oil microcapsules. According to the dry-heat aging test, β-cyclodextrin was thermostable under the high temperature conditions, and it was beneficial to reduce the emission of C. osmophloeum leaf oil. Leaf oil microcapsules exhibited high xanthine oxidase inhibitory activity, with an IC50 value of 83.3 µg/mL. It is concluded that the lifetime of C. osmophloeum leaf oil can be effectively improved by microencapsulation, and leaf oil microcapsules possess superior xanthine oxidase inhibitory activity.