Jinhua Hecha – A fermented green tea improves sleep via regulating glutamatergic synapses and gut microbiota

• Jinhua Hecha (JHHC) is a fermented green tea characterized by high amino acid and low tea polyphenols. • JHHC is believed to have a role in improving sleep. • The gut microbiome and transcriptome sequencing provide insights. • JHHC improve the sleep state of mice by suppressing central excitability through regulating glutamatergic synapses levels. Quality sleep is crucial for preserving the internal equilibrium of the body. Sleep problems have become a predominant global health concern in recent years. Jinhua Hecha (JHHC) is a fermented green tea characterized by high amino acid and low tea polyphenols. In animal experiments, the potential beneficial effects of JHHC on sleep quality were evaluated. 50 mice were categorized into five groups: the normal control (NC) group, the FFZR positive control group, the JHHCG (2.3 g/kg) group, the JHHCZ (1.6 g/kg) group, and the JHHCD (0.7 g/kg) group. The sleep experiments revealed that mice from the JHHC group exhibited a notably extended duration of sleep following the intraperitoneal injection of pentobarbital sodium, with a shortened sleep latency after injection of barbital sodium. These results suggest that JHHC is beneficial for sleep. Mechanistically, transcriptome KEGG enrichment analysis revealed that differentially expressed genes were significantly enriched in the glutamatergic synapse signaling pathway. Immunohistochemistry and multiple immunofluorescence techniques showed decreased protein expressions of GLS, VGLUT2, GluA2, GluA4, GluK1, and mGluR1 in the colon of the JHHC group. Furthermore, an increase in beneficial bacteria such as Lactobacillus, Ligilactobacillus, and Akkermansia, as well as a decrease in Alistipes, were observed in the JHHC group. These results indicate that JHHC can improve sleep, with potential mechanisms involving gut microbiota maintenance and glutamate level reduction.