White tea has been scientifically proven to exhibit positive biological effects in combating chronic diseases, including cancer, metabolic syndrome, etc. Nevertheless, the anti-aging activity and mechanism of white tea on organisms exposed to a high-fat diet remain unexplored. Herein, we prepared a white tea aqueous extract (WTAE) from white peony in Fuding and assessed its in vivo antioxidant and anti-aging effects by employing a Drosophila melanogaster senescence model induced by lard, delving into the underlying molecular mechanisms through which the WTAE contributes to lifespan improvement. Notably, the WTAE significantly extended the lifespan of Drosophila fed a high-fat diet and partially restored the climbing ability of Drosophila on a high-fat diet, accompanied by increased activities of copper-zinc superoxide dismutase, manganese-superoxide dismutase, and catalase and decreased lipid hydroperoxide levels in Drosophila. Furthermore, transcriptomic analysis indicated that the WTAE countered aging triggered by a high-fat diet via activating oxidative phosphorylation, neuroactive ligand–receptor interactions, and more pathways, as well as inhibiting circadian rhythm-fly, protein processing in the endoplasmic reticulum, and more pathways. Our findings suggest that WTAE exhibits excellent inhibitory activity against high-fat diet-induced senescence and holds promising potential as an anti-aging agent that can be further developed.

This study enhanced the odor retention of instant black tea powder by utilizing ultrasonic-assisted extraction and β-cyclodextrin embedding technology. Through single-factor tests considering variables such as the tea-to-water ratio, extraction temperature, ultrasonic extraction duration, and β-cyclodextrin addition, the optimal extraction conditions were determined. The ideal parameters were identified as follows: β-cyclodextrin was added at a rate of 7.5%, the tea-to-water ratio was 1:16, the ultrasonic extraction temperature was 52 °C, and the extraction duration was 30 min, and then the extract was processed by freeze-drying to obtain instant tea powder. Electronic nose trials revealed that the primary volatile odor compounds distinguishing the 14 groups of instant black tea soups were sulfides, terpenes, nitrogen oxides, alkanes, and aromatic compounds. HS-SPME-GC-MS analysis identified 65 effective volatile compounds, among which 11 key odor compounds, including Benzyl alcohol, Phytol, phenylethyl alcohol, 1,6,10-Dodecatrien-3-ol,3,7,11-trimethyl-,(E)-, Benzeneacetaldehyde, Undecanoic acid, ethyl ester, Dodecanoic acid, ethyl ester, Tetradecane, 2,4-Di-tert-butylphenol, 2-Pentadecanone, 6,10,14-trimethyl-, and indole, were the main contributors to the odor profile of instant black tea. The instant black tea powder produced under these conditions exhibited high quality, providing a valuable reference for further research on the production process of instant black tea powder.

L-theanine is a bioactive non-protein amino acid predominantly derived from tea plants (Camellia sinensis), widely recognized for its potential benefits in mood regulation and psychological health. Despite its promising neuropsychological profile, the specific molecular targets and mechanisms underlying its antidepressant activity remain incompletely understood. In the present study, an integrated network pharmacology strategy, combined with molecular docking and molecular dynamics (MD) simulations, was employed to systematically elucidate the potential antidepressant mechanisms of L-theanine. By intersecting predicted drug targets with depression-related genes, 40 potential targets were identified. Protein–protein interaction (PPI) network analysis subsequently pinpointed five hub targets: PRKACA, GRIA2, GRIN1, GRIA1, and HTR1A. Functional enrichment analyses (KEGG and GO) indicated that these targets are primarily implicated in critical pathological processes of depression, including neurotransmitter regulation, glutamatergic synaptic transmission, stress response signaling, and neurotrophin-related pathways. Molecular docking revealed favorable binding affinities between L-theanine and the key targets. Furthermore, MD simulations and binding free energy calculations corroborated the structural stability and thermodynamic favorability of these protein–ligand complexes. Overall, this study provides hypothesis-generating insights into the antidepressant mechanisms of L-theanine from a multi-target perspective, offering a theoretical foundation to guide future experimental validation in depression research.

Tea polysaccharide preparations obtained from five successive leaf positions (L1–L5) and stem tissue (S) of Camellia sinensis cv. Rougui were compared to characterize developmental variation in their physicochemical and functional properties. Extraction yield increased from L1 to L4 and then declined, while neutral sugar content generally increased with leaf maturity. Monosaccharide composition and apparent molecular weight distribution also varied markedly, with peak molecular weight increasing from 70.5 kDa in L1 to approximately 804 kDa in L4 and L5. Antioxidant activities differed among assays and were associated more consistently with protein and tea polyphenol contents than with individual carbohydrate traits, indicating that the measured activities reflected the composite composition of the crude polysaccharide preparations. Phytohormone profiling and transcriptomic analysis of four representative tissues (L2, L3, L4, and S) showed tissue-dependent variation in endogenous hormone profiles and in genes related to carbohydrate metabolism, nucleotide-sugar interconversion, galacturonan-related biosynthesis, and pectin-related modification. Exploratory tissue-level correlations were used to prioritize 14 candidate genes associated with representative polysaccharide traits. Given the limited number of shared tissue types included in the integrated analyses, these associations remain exploratory and do not provide evidence for direct hormonal or transcriptional regulation. Overall, tea polysaccharide characteristics varied substantially with leaf developmental position and tissue type, supporting the selection of tea raw materials according to targeted polysaccharide properties.

White tea (WT) and Indocalamus latifolius leaves (ILLs) are valued for their distinctive aromas and bioactive properties. In this study, flavonoid extraction from ILLs was optimized using total flavonoid yield as the response variable through single-factor experiments and response surface methodology. The resulting Indocalamus latifolius leaf extract (ILLE) was vacuum-concentrated and sprayed onto WT to produce Indocalamus latifolius leaf–white tea (IT). The effects of spray ratio, spraying liquid temperature, and drying temperature on the sensory and chemical qualities of IT were further evaluated. Untargeted metabolomics was performed to compare the metabolite profiles of IT and WT. The optimal extraction conditions for ILLs’ flavonoids were 95 °C, 120 min, and a liquid-to-solid ratio of 60:1 mL/g, yielding 4.39 mg/g total flavonoids. The optimal processing parameters for IT were a spray ratio of 1:1.75 g/g, a spraying liquid temperature of 50 °C, and a drying temperature of 105 °C. Compared with WT, IT showed improved sensory and biochemical qualities, including a richer and more persistent ILLs aroma, a more refreshing and more layered taste, and significantly higher levels of water extracts, flavonoids, tea polyphenols, soluble sugars, and amino acids (p < 0.05). Metabolomic analysis revealed clear compositional differentiation between IT and WT, including the enrichment of several metabolites, some with potential functional relevance, as well as aroma-active compounds. These findings provide chemical and sensory evidence for the distinctive quality of IT and support further development of this novel specialty tea.

Type 2 diabetes mellitus (T2DM) imposes a growing global health burden, and tea-processing by-products (e.g., stems) remain underutilized despite being rich in bioactive polysaccharides. This study characterized tea stem polysaccharides (TSPs) and assessed their hypoglycemic effects and the underlying mechanisms in T2DM mice. TSP was identified as an acidic heteropolysaccharide rich in galacturonic acid. Four-week oral TSP administration significantly reduced fasting blood glucose (FBG, p < 0.01) and improved glucose tolerance, as evidenced by a decreased area under the curve of the oral glucose tolerance test (OGTT-AUC) (p < 0.01), while dose-dependently alleviating pancreatic, hepatic and cecal histopathological damage. Integrated 16S rRNA sequencing and untargeted metabolomics revealed that TSP selectively enriched Lactobacillus and Ligilactobacillus and modulated amino acid and carbon metabolism pathways. Targeted metabolomics further showed that TSP induced an upward trend in the levels of some branched short-chain fatty acids (SCFAs). As a prebiotic, TSP improves T2DM metabolic disorders via the gut microbiota-metabolite axis, supporting the high-value utilization of tea stem by-products.