Ziziphi Spinosae Semen Flavonoid Ameliorates Hypothalamic Metabolism and Modulates Gut Microbiota in Chronic Restraint Stress-Induced Anxiety-like Behavior in Mice

Ziziphi Spinosae Semen (ZSS), a homology of medicine and a type of seed, has been widely used to improve sleep quality. The present study aimed to assess the effects of ZSS flavonoid (ZSSF) extracted and isolated from ZSS on gut microbiota and hypothalamus metabolomic profiles in a chronic restraint stress (CRS)-induced anxiety mouse model. ZSSF was prepared using microporous resin chromatography, and seven compounds were determined by UPLC-MS. ZSSF treatment dramatically reduced anxiety-like behaviors, exerted sedative-hypnotic effects, increased hippocampal 5-HT and 5-HTP, and enhanced intestinal barrier function through inhibiting colon ZO-1, Claudin-1, and Occludin expression and reducing TNF-α, IL-6, and IL-1β levels. Compared with the CRS group, the diversity of gut microbiota in ZSSF-group mice was increased, with an increase in <i>Bacteroidetes</i> and a decrease in <i>Firmicutes</i>, and it was accompanied by an increase in fecal SCFAs. Hypothalamus metabolomics and lipidomics were performed to achieve 25 differential metabolites and 44 lipids, respectively. Serum metabolomics showed a total of 13 metabolites associated with anxiety were remarkably regulated by ZSSF. Weighted correlation network analysis (WGCNA) showed that glycerophospholipids (GPs) as well as phenylalanine, tyrosine, and L-tryptophan in peripheral and central parts were significant metabolites, which contributed to the pharmacological action of ZSSF. The mRNA expression of TPH2 and DDC key enzymes associated with tryptophan metabolism were upregulated, and PLA2G12A, LACT, and PLA2G6 key enzymes associated with GP metabolism were downregulated in ZSSF compared with CRS. Briefly, ZSSF improved tryptophan and GP metabolism and regulated the gut microbiome. This study may lay a theoretical basis for potentially developing ZSSF as a natural functional food ingredient for the improvement of anxiety and sleep disorders.