Introduction: Some studies have shown the effectiveness of tea in reducing depression. Gut flora dysfunction is strongly associated with depression. The mechanism by which Ziyan green tea ameliorates depression is not clear.Methods: In this study, we examined the impact of Ziyan green tea on mice exhibiting symptoms similar to depression. We specifically focused on the role of intestinal flora and its metabolites. We first established a chronic unpredictable mild stress (CUMS) mouse model to induce depressive symptoms and conducted behavioural tests, biochemical tests, and pathological tissue analysis. We also investigated gut microbiota changes by 16S rRNA sequencing and measured faecal metabolites in mice using UHPLC-MS/MS.Results: The results showed that Ziyan green tea intervention improved depression-like behaviour, neurobiochemical factors, and reduced levels of pro-inflammatory factors in CUMS mice. Spearman’s correlation analysis showed that different microbial communities (Corynebacterium, Faecalibaculum, Enterorhabdus, Desulfovibrio) correlation with differential metabolites (Cholic acid, Deoxycholic acid, etc.) and depression-related biochemical indicators (5-HT, DA, BDNF, IL-6, and TNF-α).Discussion: In conclusion, our findings suggest that both low and high-dose interventions of Ziyan green tea have positive preventive effects on CUMS mice without dose dependence, partly because they mainly affect intestinal Purine Metabolism, Bile Acid Biosynthesis and Cysteine Metabolism in CUMS mice, thus stimulating brain 5-HT, DA and BDNF, and decreasing the inflammatory factors IL-6, TNF-α, activate the composition of intestinal flora, improve the intestinal flora environment and thus promote the production of intestinal metabolites, which can be used for depression treatment. It is suggested that Ziyan green tea may achieve an antidepressant effect through the gut-microbiota-brain axis.

Zhuyecha (ZYC, Camellia sp.) is a newly discovered special wild tea plant resource in Cangwu County, Wuzhou City, Guangxi Province, China. However, there have been few scientific studies on it. This study investigated its morphological and chemical characteristics. The results revealed that ZYC is an arbor-type, upright plant with lanceolate leaves. The flower has five petals, five sepals, a trifid style, and a glabrous ovary. ZYC exhibited a unique chemical profile distinguished from common tea cultivars. Compared with the control cultivated varieties (Hongyan 12, Fuyun 6, and Yinghong 9), ZYC fresh leaves contained significantly higher contents of theobromine, theophylline, and gallic acid, but considerably lower caffeine and lower total catechins. The principal catechins were epi-form/galloylated catechins EGCG and ECG. Notably, theobromine was the most abundant alkaloid in ZYC, followed by caffeine and theophylline. In ZYC fresh leaves, 15 differential non-volatile metabolites were identified, and 22 key aroma compounds were screened, including linalool, (E)-2-hexenal, hexanal, heptan-2-ol, and β-myrcene, among others. The volatile components were primarily alcohols, aldehydes, and esters, contributing to floral, fruity, and green aroma attributes. This work enhances the understanding of the botanical and phytochemical properties of ZYC and provides scientific guidance for further research and efficient utilization of this natural low-caffeine/high-theobromine tea resource.