Search Results (273)

Tea polyphenol oxidase (CsPPO) is a crucial enzyme involved in the production of tea and tea products. However, the recombinant expression of CsPPO in microorganisms is often hindered by challenges such as inclusion body formation and extremely low enzyme activity. In this study, the CsPPO gene (1800 bp) from Camellia sinensis cv. Yihongzao was cloned and 14.5% of its codons were optimized for Pichia pastoris expression. Compared to pre-optimization, codon optimization significantly enhanced CsPPO production in P. pastoris KM71, yielding a 42.89-fold increase in enzyme activity (1286.67 U/mL). The optimal temperature and pH for recombinant CsPPO were determined to be 40 °C and 5.5, respectively. This study demonstrates that codon optimization effectively improves the expression of plant-derived enzymes such as CsPPO in eukaryotic expression systems. Future research should explore the long-term stability of recombinant CsPPO and its potential applications in tea fermentation processes and functional food development. Full article

The increasing prevalence of cancer necessitates the development of novel and effective therapeutic agents. This study evaluates the anticancer potential of biosynthesized copper oxide nanoparticles (CuO NPs) using Camellia sinensis extract against human colon and breast cancer cells. The CuO NPs were characterized using various techniques to confirm their structure, size, morphology, and functional groups. The average size of CuO NPs synthesized was 20–60 nm, with spherical shape. The cytotoxic effects of these CuO NPs reveal a dose-dependent reduction in cell viability with 50% inhibitory concentration (IC₅₀) at 58.53 ± 0.13 and 53.95 ± 1.1 μg/mL, respectively. Further investigation into the mechanism of action was conducted using flow cytometry and apoptosis assays, which indicated that CuO NPs induced cell cycle arrest and apoptosis in cancer cells. Reactive oxygen species (ROS) generation, caspase activity assay, and comet assay were also performed to elucidate the underlying pathways, suggesting that oxidative stress and DNA damage play pivotal roles in the cytotoxicity observed. Overall, our findings demonstrate that biosynthesized CuO NPs exhibit notable anticancer activity against colon and breast cancer cells, with moderate selectivity over normal cells, highlighting their potential as a therapeutic agent due to their biocompatibility. However, further studies are required to validate their selectivity and safety profile. Full article

Green tea, derived from the unoxidized leaves of Camellia sinensis (L.) Kuntze, is one of the least processed types of tea and is rich in antioxidants and polyphenols. Among these, catechins—particularly epigallocatechin gallate (EGCG)—play a key role in regulating cell signaling pathways associated with various chronic conditions, including cardiovascular diseases, neurodegenerative disorders, metabolic diseases, and cancer. This review presents a comprehensive analysis of recent clinical studies focused on the therapeutic benefits and potential risks of interventions involving green tea extracts or EGCG. A systematic literature survey identified 17 relevant studies, classified into five key areas related to catechin interventions: toxicity and detoxification, drug pharmacokinetics, cognitive functions, anti-inflammatory and antioxidant properties, and obesity and metabolism. Findings from these clinical studies suggest that the health benefits of green tea catechins outweigh the potential risks. The review highlights the importance of subject genotyping for enzymes involved in catechin metabolism to aid in interpreting liver injury biomarkers, the necessity of assessing drug–catechin interactions in clinical contexts, and the promising effects of topical EGCG in reducing inflammation. This analysis underscores the need for further research to refine therapeutic applications while ensuring the safe and effective use of green tea catechins. Full article

Background/Objectives: Ultraviolet B (UVB) radiation contributes significantly to skin aging and skin disorders by promoting oxidative stress, inflammation, and collagen degradation. Natural antioxidants such as theaflavins and thearubigins from Camellia sinensis L. (black tea) have shown photoprotective effects. This study aimed to optimize the extraction of theaflavins and thearubigins from black tea leaves and evaluate the efficacy of the extract against UVB-induced damage using a transfersome-based topical formulation. Methods: Extraction of theaflavins and thearubigins was optimized via response surface methodology (Box-Behnken Design), yielding an extract rich in active polyphenols. This extract was incorporated into transfersomes that were characterized for size, polydispersity, zeta potential, storage stability, and entrapment efficiency. Human dermal fibroblasts (NHDF) were used to assess cytotoxicity, protection against UVB-induced viability loss, collagen degradation, and expression of inflammatory (IL6, COX2, iNOS) and matrix-degrading (MMP1) markers. Cellular uptake of the extract’s bioactive marker compounds was measured via LC-MS/MS. Results: The transfersomes (~60 nm) showed a good stability and a high entrapment efficiency (>85%). The transfersomes significantly protected NHDF cells from UVB-induced cytotoxicity, restored collagen production, and reduced gene expression of MMP1, IL6, COX2, and iNOS. Cellular uptake of key extract’s polyphenols was markedly enhanced by the nanoformulation compared to the free extract. Conclusions: Black tea extract transfersomes effectively prevented UVB-induced oxidative and inflammatory damage in skin fibroblasts. This delivery system enhanced bioavailability of the extract and cellular protection, supporting the use of the optimized extract in cosmeceutical formulations targeting photoaging and UV-induced skin disorders. Full article

Soil salinization poses a significant threat to tea plant (Camellia sinensis) production by compromising its bioactive compounds, such as polyphenols, L-theanine, and caffeine, which are key contributors to the plant’s health benefits and economic value. This study investigates the Salt Overly Sensitive 1 (SOS1) gene family, a critical salt-tolerance regulator in tea plants, to elucidate its role in maintaining quality under environmental stress. Genome-wide analysis identified 51 CsSOS1 genes, with phylogenetic and synteny analyses revealing strong evolutionary conservation with Populus trichocarpa and Arabidopsis thaliana. Promoter analysis detected stress- and hormone-responsive cis-elements, indicating adaptive functions in abiotic stress. Expression profiling demonstrated tissue-specific patterns, highlighting significant upregulation of CsSOS1-15 and CsSOS1-41 under salt and drought stress. Co-expression network analysis further linked CsSOS1 genes to carbohydrate metabolism, implicating their roles in stress resilience and secondary metabolite synthesis. Our findings provide molecular insights into CsSOS1-mediated salt tolerance, proposing potential targets for preserving bioactive compounds. This work facilitates developing salt-resistant tea plant cultivars to ensure sustainable production and quality stability amid environmental challenges. Full article

Tea plant [Camellia sinensis (L.) O. Kuntze] is an economically important evergreen crop cultivated worldwide. While most tea plants have green leaves, albino cultivars with yellow or white young leaves have attracted growing interest due to their elevated levels of L-theanine, a key compound that enhances the umami flavor and overall quality of green tea. In this study, we characterized the morphological and biochemical traits of a novel albino tea cultivar, ‘Geumda’, developed in Korea. ‘Geumda’ exhibited yellow young shoots during the first flush and smaller leaves compared to the green-leaf standard cultivar, ‘Sangmok’. Although the catechin content of ‘Geumda’ was lower than that of ‘Sangmok’, it exhibited significantly higher levels of total amino acids, L-theanine, and arginine by 2.1-, 2.0-, and 9.8-fold, respectively. Transmission electron microscopy and gene expression analysis revealed that the elevated amino acid content in ‘Geumda’ was associated with impaired chloroplast development, leading to reduced chlorophyll content and diminished photosynthetic capacity. These findings suggest that ‘Geumda’, with its high concentrations of theanine and arginine and its impaired chloroplast development, represents a valuable genetic resource for the production of functional green teas enriched in umami flavor and beneficial health properties. Full article

This study explores the antioxidant activity of green tea (Camellia sinensis, GT) and peppermint (Mentha × piperita, PM) infusions, individually and in combination, focusing on how preparation methods affect their efficacy. Antiradical and intracellular antioxidant activity was assessed using DPPH, ABTS, and DCF assays, alongside interaction analysis via combination index (CI) and dose reduction index (DRI). HPLC analysis determined the polyphenolic profiles of GT and PM. GT showed the strongest antioxidant activity, with the lowest IC₅₀ values (4.81 µg/mL in DPPH, 2.70 µg/mL in ABTS, 3.71 µg/mL in DCF), indicating potent radical-scavenging potential. PM exhibited moderate antiradical capacity but similar intracellular activity (IC₅₀ = 3.80 µg/mL). Co-maceration followed by lyophilization of GT:PM extracts led to nearly additive interactions (CI~1.0) and allowed significant dose reduction (DRI up to 4.44). In contrast, post-mixed extracts showed assay-dependent effects, including antagonism in intracellular ROS inhibition (CI = 1.83). Equimolar mixtures of model polyphenols: EGCG, quercetin, and rosmarinic acid demonstrated enhanced effects, with the strongest synergy in ternary mixtures (CI = 0.67–0.86), potentially achievable in GT:PM combinations. These findings highlight that extract preparation critically influences antioxidant efficacy, supporting co-maceration as a promising strategy for developing effective functional formulations based on plant extract combinations. Full article

Natural-origin edible gels are gaining attention as innovative carriers for bioactive compounds, offering consumer-friendly formats and potential to enhance stability and bioavailability. This study aimed to develop and characterize edible gels incorporating Camellia sinensis (L.) Kuntze extract using different plant-based gelling agents, including whole flaxseeds, ground flaxseeds, medium-size oatmeal, and coarse oatmeal. The physical properties of the gels were evaluated by rheological (flow curve) and pH studies. The phytochemical composition of the green tea extract and gels with this extract and the main phenolic compounds, including catechins, gallic acid, and caffeine, were evaluated by high-performance liquid chromatography. The biopharmaceutical properties of the prepared gels were evaluated by dissolution testing. Rheological analysis revealed that oat-based gels exhibited higher viscosity (up to 24.33 Pa·s) compared to flaxseed-based gels. Despite differences in consistency, no statistically significant differences were found in total phenolic release among gel formulations (p > 0.05), except for epigallocatechin, which showed significantly higher release from coarse oatmeal gels (p > 0.05). The findings suggest that both flaxseed- and oatmeal-based gels are promising natural carriers for green tea phytochemicals, offering standardized dosing and potential cognitive health benefits. Further studies are warranted to assess the in vivo bioavailability and long-term stability of these formulations. Full article

The co-fertilization of nitrogen (N) and zinc (Zn) offers significant advantages in improving the growth and development of tea plants (Camellia sinensis L). However, the corresponding responses of rhizosphere microecology remain unclear. In this study, a pot experiment was performed to investigate the effects of N-Zn co-fertilization on rhizosphere soil’s N availability, the rhizobacterial community and the metabolism of tea plants. N-Zn co-fertilization significantly increased the soil total of N, NH₄⁺-N and NO₃⁻-N contents. 16S rRNA sequencing found that N-Zn co-fertilization recruited rhizobacteria associated with N cycling and Zn activation, including Proteobacteria, Acidobacteriota and Gemmatimonadota, resulting in complex rhizobacterial networks. Metabolomics analysis indicated obvious interferences in the metabolisms of lipids, amino acids and cofactors and vitamins after fertilization. PLS-PM analysis suggested that fertilization had both direct and indirect influences on the rhizobacterial community and differential metabolites. RDA models identified pH (R² = 0.734, p < 0.01; R² = 0.808, p < 0.01) and total N (R² = 0.633, p < 0.05; R² = 0.608, p < 0.01) as dominant factors influencing both the rhizobacterial community and differential metabolites. Finally, network analysis found significant associations between rhizobacteria related to N cycling and Zn mobilization and metabolic processes involved in N metabolism and responses to Zn stress. These findings underscored that appropriate N-Zn co-fertilization is crucial for the rhizosphere soil’s N availability and the microenvironment of tea plants. Full article

Ecological factors directly influence the growth and metabolism of tea plants (Camellia sinensis L.), and unfavorable environmental conditions cause abiotic stress to them. Abiotic stress causes damage to reliable, high-quality, and safe tea production, yet the optimal ecological conditions for enhancing both yield and quality remain unclear. To investigate the response patterns of shoot growth to ecological factors and its relationship with catechin accumulation, this study conducted the cultivation of tea plants with a precise modulation of both individual and combined ecological parameters. Under 30 °C and 90% air humidity, specific combinations of light intensity and substrate relative humidity (“250 µmol·m⁻²·s⁻¹ + 65%” or “350 µmol·m⁻²·s⁻¹ + 70%”) significantly enhanced growth and yield. A significant correlation between shoot growth and catechin accumulation was observed, and mathematical models further revealed a synergistic response between shoot growth capacity and total catechin content to ecological factors. Furthermore, co-expression analysis indicated that catechin biosynthesis-related genes exhibited coordinated expression with key growth-related genes, including CsTCP, CsErf, and CsXth. In conclusion, these findings identify optimal ecological conditions to mitigate abiotic stress and reveal a synergistic relationship between catechin biosynthesis and shoot growth, providing an ecological basis for balancing yield and quality in tea production. Full article

Matcha, a finely powdered green tea, has been cherished in Japan for centuries, used in the traditional tea ceremony and nowadays also valued for its health-promoting properties. Cultivated under shaded conditions to enhance chlorophyll production, which gives the typical vibrant green color, matcha is rich in important bioactive compounds, including caffeine, catechins, and theanine. This study analyzes three matcha grades—ceremonial grade 1 (G1), grade 4 (G4), and food grade (FG)—to assess variations in their metabolite profiles. The Bligh–Dyer method was employed to extract polar and non-polar metabolites from organic and hydroalcoholic phases. High-performance thin-layer chromatography (HPTLC) was used for qualitative metabolite analysis, while nuclear magnetic resonance (NMR) spectroscopy was employed for both qualitative and quantitative analyses. Results reveal a decreasing gradient of amino acids and caffeine from grade 1 to food grade, while other metabolites, such as polyphenols, display an increasing trend. These findings suggest that factors such as harvesting time and leaf maturity significantly influence matcha’s chemical composition, providing a scientific basis for its quality differentiation and potential nutraceutical uses. Full article

Lead (Pb) is a toxic heavy metal that severely impairs plant growth and crop quality. Melatonin, a widely present indoleamine compound, enhances plant stress tolerance, yet its role in tea plant resistance to lead stress remains unclear. This study examined two tea genotypes with distinct anthocyanin levels, Longjing43 (LJ43) and Zijuan (ZJ), comparing their phenotype, antioxidant capacity, secondary metabolite synthesis, and lead transport gene expression under lead stress. Excessive Pb exposure caused severe oxidative stress, reducing PSII efficiency, increasing ROS accumulation, and intensifying lipid peroxidation. ZJ, with higher anthocyanin concentration, exhibited stronger lead stress resistance than LJ43. Under lead stress, melatonin promoted phenylalanine accumulation in ZJ, facilitating its conversion into anthocyanins and catechins via key gene regulation (CsC4H, CsLAR, and CsANS). Moreover, exogenous melatonin significantly reduced Pb concentrations in roots, stems, and leaves, with a more pronounced effect in ZJ (reductions of 20.46%, 53.30%, and 38.17%, respectively), which might be associated with the downregulation of Pb transport genes like CsZIP1 (notably showing a 29-fold decrease). While these results suggest that melatonin might enhance Pb stress tolerance by modulating flavonoid metabolism and restricting Pb uptake, the specific roles of anthocyanins and catechins in this process remains to be fully elucidated. Further studies are necessary to clarify the primary bioactive compounds and mechanisms involved in melatonin-mediated heavy metal stress mitigation. Full article

Water used in cleaning processes within the agri-food industry can be a vector for post-harvest contaminants, thus contributing to cross-contamination. The contamination risk is increased when water is not replaced between batches or when disinfection protocols are insufficient. Given the increasing focus in recent years on the potential of natural, non-invasive plant extracts to combat a variety of pathogens, including multidrug-resistant bacteria, environmental strains, and clinical isolates, this study aimed to evaluate the antibacterial activity of selected water-ethanol plant extracts against six opportunistic pathogens isolated from wash water in the agri-food industry, along with chromatographic analyses of the selected extracts. Plant extracts were obtained from the fruits, leaves, shoots, roots, and bark of 13 species. Antibacterial activity was assessed using the well diffusion method. The results indicated that antimicrobial activity was exhibited by six extracts: Tilia cordata Mill., Camellia sinensis, Quercus robur L., Betula pendula Roth, Rubus idaeus L., and Salix alba L. The extracts showed strain-dependent antimicrobial activity, with C. sinensis and R. idaeus up to 4.0 mm and 8.0 mm inhibition zones, respectively. P. aeruginosa and E. faecalis were the most susceptible strains, demonstrating the largest inhibition zones. In contrast, P. vulgaris and K. oxytoca were more resistant. The efficacy of the most active extracts can be linked to the presence of phytochemicals identified via GC-MS, including epicatechin, shikimic acid, quinic acid, gallic acid, and caffeine. These metabolites are known to interfere with bacterial cell structures and metabolic pathways. These studies may serve as a preliminary step toward the development of non-invasive water treatment methods for wash water. Full article

Distinguishing vegetation types from satellite images has long been a goal of remote sensing, and the combination of multi-source and multi-temporal remote sensing images for vegetation classification is currently a hot topic in the field. In species-rich mountainous environments, this study selected four remote sensing images from different seasons (two aerial images, one WorldView-2 image, and one UAV image) and proposed a vegetation classification method integrating hierarchical extraction and object-oriented approaches for 11 vegetation types. This method innovatively combines the Random Forest algorithm with a decision tree model, constructing a hierarchical strategy based on multi-temporal feature combinations to progressively address the challenge of distinguishing vegetation types with similar spectral characteristics. Compared to traditional single-temporal classification methods, our approach significantly enhances classification accuracy through multi-temporal feature fusion and comparative experimental validation, offering a novel technical framework for fine-grained vegetation classification under complex land cover conditions. To validate the effectiveness of multi-temporal features, we additionally performed Random Forest classifications on the four individual remote sensing images. The results indicate that (1) for single-temporal images classification, the best classification performance was achieved with autumn images, reaching an overall classification accuracy of 72.36%, while spring images had the worst performance, with an accuracy of only 58.79%; (2) the overall classification accuracy based on multi-temporal features reached 89.10%, which is an improvement of 16.74% compared to the best single-temporal classification (autumn). Notably, the producer accuracy for species such as Quercus acutissima Carr., Tea plantations, Camellia sinensis (L.) Kuntze, Pinus taeda L., Phyllostachys spectabilis C.D.Chu et C.S.Chao, Pinus thunbergii Parl., and Castanea mollissima Blume all exceeded 90%, indicating a relatively ideal classification outcome. Full article

Tea (Camellia sinensis L.) disease detection in complex field conditions faces significant challenges due to the scarcity of labeled data. While current mainstream visual deep learning algorithms depend on large-scale curated datasets. To address this, we propose a novel few-shot end-to-end detection network called MAF-MixNet that achieves robust detection with minimal annotation data. The network effectively overcomes the bottleneck of insufficient feature extraction under limited samples of existing methods, through the design of a mixed attention branch (MA-Branch) and a multi-path feature fusion module (MAFM). The former extracts contextual features, while the latter combines and enhances the local and global features. The entire model uses a two-stage paradigm to pretrain on public datasets and fine-tune on balanced subset datasets, including novel tea disease classes, anthracnose, and brown blight. Comparative experiments with six models on four evaluation metrics verified the advancement of our model. At 5-shot, MAF-MixNet achieves scores of 62.0%, 60.1%, and 65.9% in precision, nAP50, and F1 score, respectively, significantly outperforming other models. Similar superiority is achieved in the 10-shot scenario, where nAP50 is 73.8%. Our model maintains a certain computational efficiency and achieves the second fastest inference speed at 11.63 FPS, making it viable for real-world deployment. The results confirm MAF-MixNet’s potential to enable cost-effective, intelligent disease monitoring in precision agriculture. Full article