Characterization and Improvement of Sleep Activity of <i>Ziziphi Spinosae Semen</i> Oil Microcapsules Prepared by Complex Coacervation

Objective: Ziziphi Spinosae Semen oil (ZSSO) is a fatty oil extracted from Ziziphi Spinosae Semen, and its main component is unsaturated fatty acid. It is susceptible to oxidation and deterioration. The aim of this study was to improve the stability of ZSSO and protect its quality. Methods: gelatin-sodium alginate was used as the wall material for the preparation of ZSSO microcapsules by the complex coacervation. The particle size and zeta potential of the microcapsules were determined using a Malvern particle size meter. The microstructure and stability of the microcapsules were determined by SEM, FTIR, TGA and PV. The sleep-improving activity of the microcapsules was also determined by sleep induction assay, Elisa and HE staining. Results: The encapsulation efficiency of microcapsules was 56.08% ± 0.19%, average particle size was 166.17 nm, and zeta potential was 38.2. Morphology of microcapsules was observed by SEM. The FTIR results showed that the fatty oil was successfully embedded, and PV indicated that microcapsules had a slow oxidation rate. A preliminary study on the sleep-improving activity of ZSSO and microcapsules demonstrated that it could shorten sleep latency and prolong sleep time of insomniac mice, and increase the levels of 5-HT and GABA and decrease the level of Glu in the brain of mice. In addition, ZSSO and microcapsules can repair damaged neuronal cells in the hypothalamus of insomniac mice to improve sleep. Conclusion: The quality evaluation of the microcapsules indicates that the prepared ZSSO-MPs have a small particle size and good stability. Moreover, ZSSO and microcapsules can effectively improve the sleep status of insomnia mice.