This research was performed in order to investigate the alleviative effect of aged Wuyi rock tea on dextran sulfate sodium (DSS)-induced colitis in mice. Fifty C57BL/6JGpt female mice were randomly and equally divided into five groups: control, DSS, DSS + infusion of 20-year-old Wuyi rock tea (DSS + OT01), DSS + infusion of 10-year-old Wuyi rock tea (DSS + OT11) and DSS + infusion of fresh Wuyi rock tea (DSS + OT20). The physiological and histopathological conditions of mice after Wuyi rock tea interventions, and the changes of serum inflammatory factors and cecal microbiota were analyzed. The results showed that aged Wuyi rock tea could significantly alleviate the symptoms of body mass loss, diarrhea, bloody stool, and colon length shortening, reduce inflammatory cell infiltration, and significantly inhibit the secretion of pro-inflammatory cytokines. In addition, aged Wuyi rock tea could alleviate the disorder of the gut microbiota, significantly down-regulate the relative abundance of Proteobacteria, Enterobacteriaceae and Escherichia, and up-regulate the relative abundance of Verrucomicrobia and Akkermansia. In summary, aged Wuyi rock tea can alleviate DSS-induced colitis in mice, and the tea produced in 2011 is more effective than that produced in 2001, which may be due to proper oxidation of catechins such as epigallocatechin gallate to produce thearubigins, with better anti-inflammatory and antioxidant properties. In addition, aged Wuyi rock tea is able to maintain intestinal homeostasis by regulating the relative abundance of Escherichia and Akkermansia in the intestine, which in turn alleviates the symptoms of DSS-induced colitis in mice such as body mass loss, diarrhea, bloody stool, colon length shortening, mucosal and crypt damage, inflammatory cell infiltration, and serum inflammatory factor overexpression.

Tea shoots consisting of one bud and two leaves from three tea strains/varieties in Hunan Province, Rucheng Baimao 1 (RT1), Rucheng Baimao 2 (RT2), and Rucheng Baimao Quntizhong (group variety, QT3) were picked and separately processed into white tea using the same procedure involving withering and drying, whose aroma characteristics and volatile components were evaluated by quantitative descriptive analysis (QDA) and analyzed qualitatively and quantitatively by headspace-solid phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography-quadrupole time-of-flight mass spectrometry (GC × GC-QTOF-MS), respectively. Partial least squaresdiscriminant analysis (PLS-DA) and relative odor activity value (ROAV) were combined to identify the key aroma components of Rucheng Baimao white tea and to explore the impacts of different tea tree varieties on the aroma of white tea. The results showed that the sensory aroma characteristics of the three varieties of Rucheng Baimao white tea differed from one another. Both RT1 and QT3 exhibited floral aromas; RT1 had a pronounced fresh aroma, while QT3 had a prominent tip aroma. RT2 exhibited a minty aroma. Multivariate statistical analysis showed that using variable importance in the projection (VIP) score > 1 with a P value < 0.05 as well as ROAV > 1.00 as the cutoff, 10 aroma components were identified as contributors to the differences in aroma among the three varieties of white tea. Benzaldehyde played a key role in the fresh aroma of all white tea samples. Hexanal was the key to the fresh aroma of RT1. Benzaldehyde, linalool oxide II, and linalool oxide I significantly contributed to the minty aroma of RT2. 1-Octen-3-ol, citral, and (Z)-4-heptenal were crucial for the tip aroma of QT3. This study provides a theoretical reference for the diversification of aroma types of Rucheng white tea and for understanding the material basis for the key aroma compounds in Rucheng white tea produced from different tea strains/varieties.