Camellia Sinensis Research Articles

Antidiabetic Potential of Tea and Its Active Compounds: From Molecular Mechanism to Clinical Evidence.

Diabetes mellitus (DM) is a chronic endocrine disorder that poses a long-term risk to human health accompanied by serious complications. Common antidiabetic drugs are usually accompanied by side effects such as hepatotoxicity and nephrotoxicity. There is an urgent need for natural dietary alternatives for diabetic treatment. Tea (Camellia sinensis) consumption has been widely investigated to lower the risk of diabetes and its complications through restoring glucose metabolism homeostasis, safeguarding pancreatic β-cells, ameliorating insulin resistance, ameliorating oxidative stresses, inhibiting inflammatory response, and regulating intestinal microbiota. It is indispensable to develop effective strategies to improve the absorption of tea active compounds and exert combinational effects with other natural compounds to broaden its hypoglycemic potential. The advances in clinical trials and population-based investigations are also discussed. This review primarily delves into the antidiabetic potential and underlying mechanisms of tea active compounds, providing a theoretical basis for the practical application of tea and its active compounds against diabetes.

Physiological and Transcriptome Analyses Reveal the Protective Effect of Exogenous Trehalose in Response to Heat Stress in Tea Plant (Camellia sinensis)

It is well known that application of exogenous trehalose can enhance the heat resistance of plants. To investigate the underlying molecular mechanisms by which exogenous trehalose induces heat resistance in C. sinensis, a combination of physiological and transcriptome analyses was conducted. The findings revealed a significant increase in the activity of superoxide dismutase (SOD) and peroxidase (POD) upon treatment with 5.0 mM trehalose at different time points. Moreover, the contents of proline (PRO), endogenous trehalose, and soluble sugar exhibited a significant increase, while malondialdehyde (MDA) content decreased following treatment with 5.0 mM trehalose under 24 h high-temperature stress (38 °C/29 °C, 12 h/12 h). RNA-seq analysis demonstrated that the differentially expressed genes (DEGs) were significantly enriched in the MAPK pathway, plant hormone signal transduction, phenylpropanoid biosynthesis, flavone and flavonol biosynthesis, flavonoid biosynthesis, and the galactose metabolism pathway. The capability to scavenge free radicals was enhanced, and the expression of a heat shock factor gene (HSFB2B) and two heat shock protein genes (HSP18.1 and HSP26.5) were upregulated in the tea plant. Consequently, it was concluded that exogenous trehalose contributes to alleviating heat stress in C. sinensis. Furthermore, it regulates the expression of genes involved in diverse pathways crucial for C. sinensis under heat-stress conditions. These findings provide novel insights into the molecular mechanisms underlying the alleviation of heat stress in C. sinensis with trehalose.

CsMIEL1 effectively inhibits the accumulation of anthocyanins under low temperatures in tea plants (Camelliasinensis)

Tea is one of the most prevalent non-alcoholic beverages. The leaves of tea plants hyperaccumulate anthocyanins under cold stress, resulting in enhanced bitterness. Previously, we determined that the RING-type E3 ubiquitin ligase CsMIEL1 from the tea plant (Camellia sinensis (L.) O. Kuntze) is involved in the response to stress conditions. This study aimed to determine the role of CsMIEL1 in anthocyanin accumulation at the post-translational modification level. The results showed that the heterologous expression of CsMIEL1 led to an 86% decrease in anthocyanin levels, resulting in a significant decrease in the mRNA levels of related genes in Arabidopsis at low temperatures but no significant differences in other phenotypes. Furthermore, multi-omics analysis and yeast two-hybrid library screening were performed to identify potential downstream targets of CsMIEL1. The results showed that the overexpression of CsMIEL1 resulted in 45% (448) of proteins being differentially expressed, of which 8% (36) were downregulated in A.thaliana, and most of these differentially expressed proteins (DEPs) were clustered in the plant growth and secondary metabolic pathways. Among the 71 potential targets that may interact with CsMIEL1, CsMYB90 and CsGSTa, which are related to anthocyanin accumulation, were selected. In subsequent analyses, these two proteins were verified to interact with CsMIEL1 via yeast two-hybrid (Y2H) and pull-down analyses in vitro. In summary, we explored the potential mechanism by which the E3 ligase relieves anthocyanin hyperaccumulation at low temperatures in tea plants. These results provide a new perspective on the mechanisms of anthocyanin regulation and the molecular breeding of tea plants.

Drivers of Adoption: Mechanical Harvesting in the Corporate Sector Tea Plantations in Sri Lanka

Tea industry experts emphasize that selective manual harvesting is the best way to maintain leaf quality while preserving tea plant health. However, tea plantations tend to adopt mechanical harvesting to overcome labour shortages and harvesting costs. But the adoption of mechanical harvesting is still low, prompting further investigations. The purpose of this study is to investigate tea plantation managers’ concerns about the factors influencing mechanical harvesting adoption based on a case study as the research strategy. The results demonstrated that the majority of determinants that emerged, as drivers are consistent with the latent constructs, defined in adoption theories. Key drivers are employees’ attitudes, facilitation, continuous monitoring, training of women and skill development through regular practice. The organizational factors that cannot be explained through adoption theories were isolated. The findings concluded that multi-dimensional factors have emerged as the driving force, which will be useful to anyone looking into the real application.

High-density genetic map construction and QTL mapping of a zigzag-shaped stem trait in tea plant (Camellia sinensis)

The highly unique zigzag-shaped stem phenotype in tea plants boasts significant ornamental value and is exceptionally rare. To investigate the genetic mechanism behind this trait, we developed BC1 artificial hybrid populations. Our genetic analysis revealed the zigzag-shaped trait as a qualitative trait. Utilizing whole-genome resequencing, we constructed a high-density genetic map from the BC1 population, incorporating 5,250 SNP markers across 15 linkage groups, covering 3,328.51 cM with an average marker interval distance of 0.68 cM. A quantitative trait locus (QTL) for the zigzag-shaped trait was identified on chromosome 4, within a 61.2 to 97.2 Mb range, accounting for a phenotypic variation explained (PVE) value of 13.62%. Within this QTL, six candidate genes were pinpointed. To better understand their roles, we analyzed gene expression in various tissues and individuals with erect and zigzag-shaped stems. The results implicated CsXTH (CSS0035625) and CsCIPK14 (CSS0044366) as potential key contributors to the zigzag-shaped stem formation. These discoveries lay a robust foundation for future functional genetic mapping and tea plant genetic enhancement.

A method for mining condition-specific co-expressed genes in Camellia sinensis based on k-means clustering

BackgroundAs one of the world’s most important beverage crops, tea plants (Camellia sinensis) are renowned for their unique flavors and numerous beneficial secondary metabolites, attracting researchers to investigate the formation of tea quality. With the increasing availability of transcriptome data on tea plants in public databases, conducting large-scale co-expression analyses has become feasible to meet the demand for functional characterization of tea plant genes. However, as the multidimensional noise increases, larger-scale co-expression analyses are not always effective. Analyzing a subset of samples generated by effectively downsampling and reorganizing the global sample set often leads to more accurate results in co-expression analysis. Meanwhile, global-based co-expression analyses are more likely to overlook condition-specific gene interactions, which may be more important and worthy of exploration and research.ResultsHere, we employed the k-means clustering method to organize and classify the global samples of tea plants, resulting in clustered samples. Metadata annotations were then performed on these clustered samples to determine the “conditions” represented by each cluster. Subsequently, we conducted gene co-expression network analysis (WGCNA) separately on the global samples and the clustered samples, resulting in global modules and cluster-specific modules. Comparative analyses of global modules and cluster-specific modules have demonstrated that cluster-specific modules exhibit higher accuracy in co-expression analysis. To measure the degree of condition specificity of genes within condition-specific clusters, we introduced the correlation difference value (CDV). By incorporating the CDV into co-expression analyses, we can assess the condition specificity of genes. This approach proved instrumental in identifying a series of high CDV transcription factor encoding genes upregulated during sustained cold treatment in Camellia sinensis leaves and buds, and pinpointing a pair of genes that participate in the antioxidant defense system of tea plants under sustained cold stress.ConclusionsTo summarize, downsampling and reorganizing the sample set improved the accuracy of co-expression analysis. Cluster-specific modules were more accurate in capturing condition-specific gene interactions. The introduction of CDV allowed for the assessment of condition specificity in gene co-expression analyses. Using this approach, we identified a series of high CDV transcription factor encoding genes related to sustained cold stress in Camellia sinensis. This study highlights the importance of considering condition specificity in co-expression analysis and provides insights into the regulation of the cold stress in Camellia sinensis.

New records of Pestalotioid species associated with leaf spot disease on Camellia sinensis from northern Thailand

Camellia sinensis (L.) Kuntze var. assamica (Miang tea) is widely distributed in northern Thailand due to its traditional and industrial attributes, including black tea and Miang production. In this study, two Pestalotioid taxa associated with C. sinensis leaf spots were collected in Mae Taeng district, Chiang Mai Province, Thailand. Species delineation was based on the evidence from morphological and multi-locus phylogenies using ITS, tub2 and tef1-α. Neopestalotiopsis saprophytica is herein reported as a new record on Camellia sinensis, while Pseudopestalotiopsis chinensis is recorded as a new geographical record from Thailand. The findings of this research have the potential to offer fresh insights into the two previously documented species within the existing fungal community associated with C. sinensis in Thailand. This, in turn, could enhance our comprehension of their interactions with the host plant in the times ahead.

Occurrence of Cassava (Manihot esculenta) Leaf Spot Disease Caused by Diaporthe ueckeri in China.

Cassava (Manihot esculenta) is a perennial crop of the family Euphorbiaceae, widely cultivated due to its phytopharmacological and economic values in China. In November 2022, a leaf spot disease on cassava was observed in Zhanjiang, Guangdong, China (21.17° N, 110.18° E), with 100% disease incidence. About 80 % of leaves were covered with spots on the infected plants. Typical symptoms initially appeared as irregular water-soaked lesions that became brown and whitish with the progress of the disease, lesions gradually expanded and coalesced, causing leaf withering, drying and final fall. Tissues (4 to 5 mm) were excised from the margin of lesions, sterilized in 3% H2O2 solution for 3 min, rinsed three times with sterile water, placed on potato dextrose agar (PDA) medium (containing 50mg/L penicillin), and incubated at 25-28 °C. Ten single hypha isolates with similar morphology were obtained and further purified as single conidium subcultures. The colony was grey whitish with sparse aerial mycelium and colony diameter reached 70.4 mm after four days incubation at 25-28℃ in the dark. Black pycnidia occurring as clusters were spherical or irregular, erumpent at maturity, often with a creamy whitish, conidial cirrus extruding from ostiole after 30-days incubation. Conidiophores were hyaline, smooth, unbranched. Alpha conidia were bi-guttulate, hyaline, ellipsoidal, aseptate, with dimensions of 5.1~7.5×1.9~3.4µm (mean 6.2×2.8 µm, n>50). Beta conidia were abundant, filiform, hyaline, smooth, curved in a hooked shape, with a truncate base and dimensions of 18.5-26.4 × 0.6-1.2μm (mean 23.4 × 1.0 μm, n= 40) . Gamma conidia were not observed. The morphological characteristics were similar to those of Diaporthe ueckeri (Udayanga et al. 2015). The internal transcribed spacer (ITS) region, large subunit (LSU) rRNA sequence, actin (ACT), calmodulin (CAL), histone H3 (HIS), translation elongation factor 1-alpha (TEF1-α), and β-tubulin (TUB) genes of a representative isolate CCAS-MS-6 (ACCC 35497) were amplified and sequenced using primer pairs: ITS5/ITS4, LR0R/LR5, ACT-512F/ACT-783R, CAL228F/CAL737R, CYLH3F/ H3-1b, EF1-728F/ EF1-986R and Bt2a/Bt2b (Gao et al 2017；Udayanga et al 2014). All sequences were deposited in GenBank (OR361671, OR361672, and OR365605-9). BLAST search showed high similarities with sequences of Diaporthe ueckeri (Tab 1). Maximum likelihood analyses of the concatenated data of CAL, HIS, ITS, TEF and TUB using Mega 11 placed CCAS-MS-6 in the D. ueckeri clade. Thus, the fungus was identified as D. ueckeri. Three one-year old healthy plants were used for pathogenicity tests in pots. Two 15-day old leaves of each plant were cleaned with 75% alcohol, three sites on each leaf were wounded, and sites on one of the leaf were covered with fungal plugs from 15-day-old cultures on PDA, and sites on the other leaf with PDA plugs as a control. All plants were kept at ambient temperature (about 28℃) and covered with plastic bags containing sterile wet cotton to maintain the humidity. Seven days after inoculation, all inoculated sites showed symptoms of necrosis, while control sites showed no symptoms. The same fungus identified on the basis of morphological and molecular criteria was reisolated from symptomatic inoculated leaves. In China, D. ueckeri had been reported to cause diseases on Eucalyptus citriodora, Camellia sinensis, and Michelia shiluensis (Gao et al 2016; Liao et al 2023; Yi et al 2018), this is the first report on M. esculenta. The definition of the disease etiology is a prerequisite to develop effective management strategies.

Gene expression regulation of the effect of shading on chlorophyll content in Fuding White Tea (Camellia sinensis L.).

Shading is an important practical method to improve the quality of green tea. Previous research of our group found that because the biosynthesis and distribution of theanine in tea plants were affected by down regulation of gene encoding amino acid permeases, theanine content in tea leaves which grown under shading condition was significantly higher than those under natural light. In this study, our group analyzed the changes of tea leaf area, free amino acid content and photosynthetic parameters under natural light and shading conditions, to ensure that moderate shading did not reduce but improve the quality of tea. Transcriptome sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted to reveal the expression levels of genes related to chlorophyll content and chlorophyll a/b ratio under natural light and shading conditions. Experimental results revealed the presence of the following differentially expressed genes (DEGs) in the porphyrin and chlorophyll metabolism pathway of tea under natural light and shading conditions: the up regulation of CPOX expression may lead to an increase in the accumulation of raw materials of chlorophyll synthesis, while the down regulation of SGR expression may lead to a decrease in chlorophyll degradation. The combined effect of these two genes may lead to an increase in the total chlorophyll content of tea. The down regulation of NOL expression may lead to the obstruction of chlorophyll b transform to chlorophyll a, that is, the decrease of the chlorophyll a/b ratio. This study investigated the molecular mechanism of chlorophyll content and component alteration in Fuding white tea under natural light and shading conditions, and elucidated the effects of different light intensities on the porphyrin and chlorophyll metabolism pathway of tea. Thus provided deep understanding of chlorophyll regulation under shading condition in tea cultivation, which could contribute to high-quality matcha production.

A functional study reveals CsNAC086 regulated the biosynthesis of flavonols in Camellia sinensis.

CsNAC086 was found to promote the expression of CsFLS, thus promoting the accumulation of flavonols in Camellia sinensis. Flavonols, the main flavonoids in tea plants, play an important role in the taste and quality of tea. In this study, a NAC TF gene CsNAC086 was isolated from tea plants and confirmed its regulatory role in the expression of flavonol synthase which is a key gene involved in the biosynthesis of flavonols in tea plant. Yeast transcription-activity assays showed that CsNAC086 has self-activation activity. The transcriptional activator domain of CsNAC086 is located in the non-conserved C-terminal region (positions 171-550), while the conserved NAC domain (positions 1-170) does not have self-activation activity. Silencing the CsNAC086 gene using antisense oligonucleotides significantly decreased the expression of CsFLS. As a result, the concentration of flavonols decreased significantly. In overexpressing CsNAC086 tobacco leaves, the expression of NtFLS was significantly increased. Compared with wild-type tobacco, the flavonols concentration increased. Yeast one-hybrid assays showed CsNAC086 did not directly regulate the gene expression of CsFLS. These findings indicate that CsNAC086 plays a role in regulating flavonols biosynthesis in tea plants, which has important implications for selecting and breeding of high-flavonols-concentration containing tea-plant cultivars.

Skin- and Eco-Friendly Hand Sanitizer: A Novel Composition of Natural Extracts to Prevent the Spread of Respiratory Viruses.

Respiratory diseases caused by viruses are a serious global health threat. Although the use of hand sanitizers containing alcohol and synthetic antiseptic agents is recognized as an effective, simple, and low-cost measure to combat viral transmission, they can harm human health and the environment. Thus, this work aimed to study the efficacy of combining Camellia sinensis and Chamomilla recutita extracts in a skin- and eco-friendly leave-on hand sanitizer to prevent the spread of respiratory viruses. An oil-in-water emulsion containing C. recutita oily extract (5.0%), C. recutita glycolic extract (0.2%) and C. sinensis glycolic extract (5.0%) showed virucidal activity against HAdV-2 (respiratory virus) and two surrogate viruses of SARS-CoV-2 (HSV-1 and MVH-3), showing great potential to prevent the spread of respiratory viruses. These natural extracts combined are also promising to combat a broad spectrum of other viruses, in the form of antiseptic mouthwashes or throat sprays, surface disinfectants, and veterinary products, among others. Complementally, the developed hand sanitizer demonstrated efficacy against bacteria and fungus.

Effect of tea green leafhopper (Empoasca onukii Matsuda) sucking on the quality of Oriental Beauty

AbstractThis study aimed to investigate the effects of tea green leafhopper damage on the sensory quality and metabolite composition of Oriental Beauty by using tea leaves from different varieties of tea plants and processing factories. The results indicated that tea green leafhopper damage could reduce bitterness and increase the level of fruity aroma, which was related to the content changes of catechin components and alcohol substances. Furthermore, the tea green leafhopper salivary treatment experiment revealed that the decrease of catechin content and increase of theaflavin content were mainly influenced by the action of saliva and mechanical injury, and changes in volatile components such as linalool oxidation were responsible for the alteration in aroma. These findings provide a theoretical reference for the aroma formation and quality improvement of Oriental Beauty.

Metabolomic responses of tea [Camellia sinensis (L.) O. Kuntze] leaves to red spider mite [Oligonychus coffeae (Nietner)] and tea mosquito bug [Helopeltis theivora Waterhouse] infestation: a GC–MS-based study

BackgroundThe tea plant, Camellia sinensis (L.) O. Kuntze, is an evergreen leafy plant whose tender leaves are used in the manufacturing of the world’s second most consumed beverage—tea. The production and consumption of tea worldwide have continually increased over the decades. All parts of the plant—leaf, stem, root, flower and seed, are fed upon by insect pests. This study elucidates the metabolomic changes occurring in tea leaves in response to infestation by two major pests in tea gardens: red spider mites and tea mosquito bugs. These pests significantly impact both the quantity and quality of tea production. The secondary metabolites produced by the tea due to pest attack has been analysed using GC–MS analysis in the laboratory.ResultsMostly fatty acid derivatives were biosynthesized as secondary metabolites due to pest attack as revealed from the result. In both infestations, methyl stearate was found to be produced along with increased chromatographic peaks of compounds such as caffeine, methyl palmitate, methyl linoleate, and stigmasta-7,25-dien-3-ol. In comparison with respective control samples (leaf with no pest attack), the one attacked by red spider mite showed eighteen exclusive metabolites, whereas tea mosquito bug infested leaf showed six such exclusive metabolites.ConclusionsSome metabolites were found to be either increased or decreased in their amount in both the samples. The increased compounds were reported with insecticidal and pesticidal properties with respect to respective controls. Some metabolites were markers of pest attacks i.e. plant defense mechanism induced phytochemicals according to the literature as discussed in this research.

Optimization of nutrient management improves productivity, quality and sustainability of albino tea cultivar Baiye-1

Proper nutrient management is crucially important to the sustainable development of tea production. Compared to normal green-leaf cultivars, albino tea cultivars produce green tea of superior quality characterized by high contents of amino acids as a result of the hydrolysis of chloroplast proteins at albinism. However, the advantage of albino tea cultivars was offset by inferior growth and yield performance because of low contents of chlorophylls and limited photosynthesis capacity. Our understanding about the nutrition characteristics of albino tea cultivars was very limited. A four-year field experiment was conducted to develop proper nutrient management for Baiye-1 to overcome its weakness of low productivity without a tradeoff in tea quality and environmental risks. The nutrient management schemes were formulated by optimizing the rate and ratio of nitrogen (N), phosphorus, potassium and magnesium together with substitution of chemical fertilizers with organic manures. The total amounts of nutrients in the optimized schemes were reduced by 25% compared to the local farmers’ practice (FP). Results showed that optimized rates and ratio of nutrients together with partial substitution of chemical fertilizers with rapeseed cake manure more considerably improved albino tea yield, the contents of free amino acids, total polyphenol and catechins relative to FP. Partial substitution of chemical fertilizers with commercial livestock manure decreased tea quality, which was likely caused by a dilution effect of increasing tea yield and decreasing N status of tea plants. Full organic substitution of chemical fertilizers by rapeseed cake manure improved tea yield and quality but had relatively low agronomic efficiency and profit. The effect of optimized nutrient management schemes was associated with the improvement of nutritional status in tea plants. The present work demonstrated that the optimization of nutrient management considerably improved albino tea yield, quality and profit while decreased the application rate of fertilizers and the intensity of greenhouse gas emissions.

Heat Transfer Process of the Tea Plant under the Action of Air Disturbance Frost Protection

Wind machines based on the air disturbance method are progressively employed to mitigate frost damage within the agricultural machinery frost protection. These devices are utilized during radiative frost nights to disrupt near-surface thermal inversion through air mixing. Despite this application, the fundamental mechanisms underlying these mixing processes are not well comprehended. In this research, numerical simulations were conducted using COMSOL Multiphysics software version 6.0 to simulate the flow and heat transfer processes between the thermal airflow and both the tea canopy and stems. The results indicated that due to obstruction from the canopy cross-section, the airflow velocity on the contact surface rapidly increased. As the airflow further progressed, the high-speed region of the airflow gradually approached the canopy surface. Turbulent kinetic energy increased initially on the windward side of the canopy cross-section and near the top interface. On the windward side of the canopy, due to the initial impact of the thermal airflow, rapid heating occurred, resulting in a noticeable temperature difference between the windward and leeward sides within a short period. In the interaction between airflow and stems, with increasing airflow velocity, fluctuations and the shedding of wake occurred on the leeward side of the stems. The maximum sensible heat flux at the windward vertex of the stem increased significantly with airflow velocity. At an airflow velocity of 2.0 m/s, the maximum heat flux value was 2.37 times that of an airflow velocity of 1.0 m/s. This research utilized simulation methods to study the interaction between airflow and tea canopy and stems in frost protection, laying the foundation for further research on the energy distribution in tea ecosystem under the disturbance of airflow for frost protection.

Investigation of heat stress responses and adaptation mechanisms by integrative metabolome and transcriptome analysis in tea plants (Camellia sinensis).

Extreme high temperature has deleterious impact on the yield and quality of tea production, which has aroused the attention of growers and breeders. However, the mechanisms by which tea plant varieties respond to extreme environmental heat is not clear. In this study, we analyzed physiological indices, metabolites and transcriptome differences in three different heat-tolerant tea plant F1 hybrid progenies. Results showed that the antioxidant enzyme activity, proline, and malondialdehyde were significantly decreased in heat-sensitive 'FWS' variety, and the accumulation of reactive oxygen molecules such as H2O2 and O2- was remarkably increased during heat stress. Metabolomic analysis was used to investigate the metabolite accumulation pattern of different varieties in response to heat stress. The result showed that a total of 810 metabolites were identified and more than 300 metabolites were differentially accumulated. Transcriptional profiling of three tea varieties found that such genes encoding proteins with chaperon domains were preferentially expressed in heat-tolerant varieties under heat stress, including universal stress protein (USP32, USP-like), chaperonin-like protein 2 (CLP2), small heat shock protein (HSP18.1), and late embryogenesis abundant protein (LEA5). Combining metabolomic with transcriptomic analyses discovered that the flavonoids biosynthesis pathway was affected by heat stress and most flavonols were up-regulated in heat-tolerant varieties, which owe to the preferential expression of key FLS genes controlling flavonol biosynthesis. Take together, molecular chaperons, or chaperon-like proteins, flavonols accumulation collaboratively contributed to the heat stress adaptation in tea plant. The present study elucidated the differences in metabolite accumulation and gene expression patterns among three different heat-tolerant tea varieties under extreme ambient high temperatures, which helps to reveal the regulatory mechanisms of tea plant adaptation to heat stress, and provides a reference for the breeding of heat-tolerant tea plant varieties.

Characterization of the key volatile compounds in longjing tea (Camellia sinensis) with different aroma types at different steeping temperatures by GC‒MS and GC‒IMS

Longjing tea (Camellia sinensis), an iconic agricultural product distinguished by its geographical indication status, has gained much acceptance and consumption in China. The aroma types and steeping conditions of green tea are important factors influencing consumer acceptance. However, the effects of steeping conditions on tea samples with different aroma types are still unknown. Explanation of the above unknowns can provide new insights into the flavor variations of tea when consumed for optimal sensory enjoyment. Here, the aroma profiles of Longjing green teas with bean-like (DX) and fresh aroma (QX) types were analyzed using gas chromatography‒mass spectrometry (GC‒MS), gas chromatography–ion mobility spectrometry (GC‒IMS), and quantitative descriptive analysis (QDA). Geraniol, (E, E)-2,4-heptadienal and other 11 compounds contributed to the bean-like aroma, while heptanal-d, hexanal-d and other 4 compounds contributed to the fresh aroma. Further, the release patterns of volatiles at different steeping temperatures were also revealed. 12 volatiles led to the differences between the two aroma types of Longjing teas at different steeping temperatures. Most volatiles exhibited their aroma characteristics when the steeping temperature exceeded 80 °C. These results enhance the comprehension of green tea's aroma profile, thereby enabling consumers to approach tea drinking from a more scientific perspective.

Anti-atherogenic role of green tea (Camellia sinensis) in South Indian smokers

Ethnopharmacological relevanceGreen tea (Camellia sinensis) is a popular beverage consumed all over the world due to its health benefits. Many of these beneficial effects of green tea are attributed to polyphenols, particularly catechins. Aim of the studyThe present study focuses on underlying anti-platelet aggregation, anti-thrombotic, and anti-lipidemic molecular mechanisms of green tea in South Indian smokers. Materials and methods: We selected 120 South Indian male volunteers for this study to collect the blood and categorised them into four groups; control group individuals (Controls), smokers, healthy control individuals consuming green tea, and smokers consuming green tea. Smokers group subjects have been smoking an average 16-18 cigarettes per day for the last 7 years or more. The subjects (green tea consumed groups) consumed 100 mL of green tea each time, thrice a day for a one-year period. ResultsLC-MS analysis revealed the presence of multiple phytocompounds along with catechins in green tea extract. Increased plasma lipid peroxidation (LPO), protein carbonyls, cholesterol, triglycerides, and LDL-cholesterol with decreased HDL-cholesterol levels were observed in smokers compared to the control group and the consumption of green tea showed beneficial effect. Furthermore, docking studies revealed that natural compounds of green tea had high binding energy with 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA) when compared to their positive controls, whereas (-) epigallocatechin-3-gallate (EGCG) and (-) epicatechin-gallate (ECG) had high binding energy with sterol regulatory element-binding transcription factor 1 (SREBP1c). Further, our ex vivo studies showed that green tea extract (GTE) significantly inhibited platelet aggregation and increased thrombolytic activity in a dose dependent manner. ConclusionIn conclusion, in smokers, catechins synergistically lower oxidative stress, platelet aggregation and modify an aberrant lipid profile. Furthermore, molecular docking studies supported green tea catechins' antihyperlipidemic efficacy through strong inhibitory activity on HMG-CoA reductase and SREBP1c. The mitigating effects on cardiovascular disease risk factors in smokers that have been reported can be attributed majorly to catechins or to their synergistic effects.

Utilization of factory tea (Camellia sinensis) wastes in eco-friendly dyeing of jute packaging fabrics

Eco-friendly dyeing of jute packaging fabrics was evaluated using aqueous extraction of factory tea (Camellia sinensis) wastes. Jute and factory tea wastes are available in Bangladesh and jute bags are used for packaging of various exportable agricultural commodities. The extract of factory tea waste (FTW) is dark coffee colored and it was characterized by attenuated total reflection-fourier transform infrared (ATR-FTIR) and microbial analysis. Nontoxic, non-allergic and eco-friendly natural dyeing process of jute packaging fabrics using extract of FTW were developed and optimized. Metal mordants 10 % on the weight of fabric was used to get the fastness properties of dyed jute fabric. The methods of application of mordants were pre-mordanting, simultaneous or meta-mordanting and post-mordanting. The color fastness and tensile properties were measured for all jute packaging fabrics and it is found that the dyed jute packaging fabrics showed a slight decrease in tensile breaking force (N) than undyed jute packaging fabric. The highest color fastness obtained with the meta mordanting method with ferrous sulfate mordant in a shade of dark coffee. The results of the color fastness for light and washing showed an excellent value of grade 4–5.

Integrative Omics Analyses of Tea (Camellia sinensis) under Glufosinate Stress Reveal Defense Mechanisms: A Trade-Off with Flavor Loss

Extensively applied glufosinate (GLU) will trigger molecular alterations in nontarget tea plants (Camellia sinensis), which inadvertently disturbs metabolites and finally affects tea quality. The mechanistic response of tea plants to GLU remains unexplored. This study investigated GLU residue behavior, the impact on photosynthetic capacity, specialized metabolites, secondary pathways, and transcript levels in tea seedlings. Here, GLU mainly metabolized to MPP and accumulated more in mature leaves than in tender ones. GLU catastrophically affected photosynthesis, leading to leaf chlorosis, and decreased Fv/Fm and chlorophyll content. Physiological and biochemical, metabolomics, and transcriptomics analyses were integrated. Showing that GLU disrupted the photosynthetic electron transport chain, triggered ROS and antioxidant system, and inhibited photosynthetic carbon fixation. GLU targeted glutamine synthetase (GS) leading to the accumulation of ammonium and the inhibition of key umami L-theanine, causing a disorder in nitrogen metabolism, especially for amino acids synthesis. Interestingly, biosynthesis of primary flavonoids was sacrificed for defensive phenolic acids and lignin formulation, leading to possible losses in nutrition and tenderness in leaves. This study revealed the defense intricacies and potential quality deterioration of tea plants responding to GLU stress. Valuable insights into detoxification mechanisms for non-target crops post-GLU exposure were offered. Environmental implicationGlufosinate, the world's second-largest herbicide with increasing production amidst rising challenges of glufosinate-resistant weeds, is extensively utilized in tea plantations. Glufosinate threatens nontargeted tea safety and consumer health by disturbing crop metabolism. This investigation delves into the intricate interplay between glufosinate and the morphological, physiological, metabolomic, and transcriptomic responses of tea plants. The disruption of nitrogen metabolism and secondary metabolite synthesis of nontargeted crops from the contaminant underscores the potential ecological consequences. Moreover, this study provides new information for the screening of biomarkers of glufosinate stress-responsive metabolites or genes and the detoxification mechanism of resistance to glufosinate stress.