On the stone-paved lanes of Songyang County that date back to ancient times,morning mist lingered as a faint fragrance of tea wafted from a century-old house.Inside,Yang Junjie,a tea maker born in the 1980s,worked def...On the stone-paved lanes of Songyang County that date back to ancient times,morning mist lingered as a faint fragrance of tea wafted from a century-old house.Inside,Yang Junjie,a tea maker born in the 1980s,worked deftly at the stove,his hands moving swiftly over the scorching iron wok as tender green tea leaves dance between his fingers.展开更多
In May 2025,the Fuding White Tea Culture System in southeast China’s Fujian Province was officially recognized by the UN Food and Agriculture Organization(FAO)as a Globally Important Agricultural Heritage System(GIAH...In May 2025,the Fuding White Tea Culture System in southeast China’s Fujian Province was officially recognized by the UN Food and Agriculture Organization(FAO)as a Globally Important Agricultural Heritage System(GIAHS).It mainly includes national-level superior varieties-Fuding Dabai Tea,Fuding Dahao Tea,and Fuding Cai Tea(group variety)which retains tradition and uses tea seeds for sexual reproduction-providing abundant germplasm resources for cultivating new tea varieties.展开更多
Vitamin C,a potent antioxidant with broad therapeutic applications,is limited by rapid degradation under environmental stressors,which compromises its stability and bioactivity.This study addresses these limitations b...Vitamin C,a potent antioxidant with broad therapeutic applications,is limited by rapid degradation under environmental stressors,which compromises its stability and bioactivity.This study addresses these limitations by formulating a double nano-emulsion(W/O/W)system incorporating macadamia oil and tea tree oil,using homogenization and phase inversion temperature(PIT)techniques.Comprehensive physicochemical charac-terization,including droplet size,polydispersity index(PDI),zeta potential,turbidity,Fourier transform infrared spectroscopy(FTIR),and SEM,was conducted alongside stability assessments under varying pH,temperature,and storage conditions.The optimized nano-emulsions exhibited nanoscale droplet sizes(10-40 nm),low PDI values(indicating high uniformity),and robust stability.Interestingly,the formulation with 2%W/O loading,with a particle size of 11.57 nm and a PDI of 0.04,demonstrated an antioxidant capacity of 4622.62μg ascorbic acid equivalents(AA)/g,which was significantly higher(p<0.05)compared to both natural oils(macadamia oil:20.91μg AA/g,tea tree oil:16.86μg AA/g)and a 10%Vitamin C aqueous solution(592.94μg AA/g).FTIR analysis confirmed the molecular integrity of Vitamin C and its successful encapsulation with macadamia and tea tree oils,while SEM images revealed uniformly spherical and well-dispersed droplets.Moreover,the formulation retained its structural integrity and antioxidant functionality under diverse pH and thermal conditions.These findings underscore the potential of double nano-emulsion systems to overcome the stability challenges of Vitamin C,offering a promising approach to enhance its bioavailability and therapeutic performance in phar-maceutical and cosmetic applications.展开更多
Selenium is one of the important trace elements in the human body.Its deficiency will directly affect human health.With people's attention to health,the content of selenium in food has gradually attracted attentio...Selenium is one of the important trace elements in the human body.Its deficiency will directly affect human health.With people's attention to health,the content of selenium in food has gradually attracted attention.However,detecting selenium compounds in complex samples remains a challenge.In this work,we built an online heating-reaction device.This device combines the electrospray extraction ionization mass spectrometry(EESI-MS)with the heating reaction device,which can simultaneously detect various selenium compounds in complex liquid samples.Under acidic conditions,the sample was heated and catalyzed by a heating reaction device,so that the SeO~(2-)_(3)and O-phenylenediamine(OPD)could generate 1,3-dihydro-2,1,3-benzoselenadiazole.Based on the above reactions,we can detect organic selenium,inorganic selenium and other compounds in liquid samples by organic mass spectrometry.In this experiment,we determined the content of three forms of selenium:selenomethionine(SeMet),l-selenocystine(SeCys(2)),and sodium selenite.The calibration curves for SeMet,SeCys(2),and sodium selenite showed strong linearity within a range of 0.50-50.00μg/L.The limits of detection(LOD)for the three compounds were 0.22,0.27,and 0.41μg/L,respectively.The limits of quantification(LOQ)were 0.68,0.81,and 1.23μg/L,respectively.Spiked recoveries at three levels ranged from 98.8%to 106.1%.In addition,this method can simultaneously detect three selenium compounds and three other specific chemical components in tea infusion samples,providing a rapid and efficient method for identifying tea quality.展开更多
China has limited acaricide options for tea plantations.Cyetpyrafen,a novel domestic acaricide with high efficacy,low toxicity and a negative temperature coefficient,offers an alternative for tea pest control;however,...China has limited acaricide options for tea plantations.Cyetpyrafen,a novel domestic acaricide with high efficacy,low toxicity and a negative temperature coefficient,offers an alternative for tea pest control;however,its residue fate in tea remains unclear.This study developed a method to simultaneously detect cyetpyrafen and its metabolites(M-309,M-325-1,and M-409-3)in different tea matrices to investigate their fate.Recoveries of compounds ranged from 73.4 to 106.2%with the relative standard deviations(RSDs)below 12.0%.During tea cultivation,the dissipation half-life of cyetpyrafen was 0.59 d,with M-309 as a major metabolite.The residues of cyetpyrafen and M-309 were affected by different processing stages,especially water loss and high temperatures during fixing,drying and withering.The total processing factors ranged from 1.39 to 1.71 for green tea and 1.48 to 2.28 for black tea(processed from fresh tea leaves sampled at 1,5,and 7 d),respectively.The leaching rates of cyetpyrafen from green tea and black tea into tea infusions were 7.4 and 6%,respectively.The risk associated with cyetpyrafen intake from tea consumption was low,with risk quotient values below 100%.However,theoretical calculation indicated potential harm to non-target organisms from its metabolites.This research provides a reference for the safe and efficient use of cyetpyrafen in tea gardens.展开更多
Vine tea is documented in ancient Chinese books as having the function of promoting blood circulation.However,its effects and mechanisms remain unclear.The aim of this study was to comprehensively investigate the prot...Vine tea is documented in ancient Chinese books as having the function of promoting blood circulation.However,its effects and mechanisms remain unclear.The aim of this study was to comprehensively investigate the protective potential and mechanisms of vine tea in high-fat diet rat through a combination of in vivo and in vitro experiments.The efficacy of vine tea was evaluated using a high-fat diet rat model and an oxidized low-density lipoprotein-treated cell model,with physiological and biochemical indicators measured in rat serum and cell supernatants.Transcriptomics was utilized to investigate alterations mRNA expression following the administration of dihydromyricetin in cell model.Metabolomics and 16S rRNA sequencing was employed to examine changes in metabolites in the serum and changes in gut microbiota of high-fat diet rats after administering vine tea extract.Vine tea extract and dihydromyricetin can reduce elevated levels of lipids,including total cholesterol and triglycerides,following modeling.Transcriptomic data indicate that dihydromyricetin exerts its effects by regulating ferroptosis signaling pathways.Metabolomic analysis demonstrates that the administration of vine tea extract influences the vitamin K cycle and glutathione,thereby alleviating the progression of ferroptosis.Additionally,16S rRNA sequencing reveals that vine tea extract increases Lactobacillaceae in the gut microbiota,which subsequently affects the levels of lysophosphatidylcholine,a major phospholipid component of oxidized low-density lipoprotein in serum.Our results indicate that vine tea can regulate ferroptosis signaling pathways and increase Lactobacillaceae in the gut microbiota,thereby exhibiting cardiovascular protective effects in high-fat diet rats.展开更多
Understanding the molecular responses of tea leaves to mechanical stress is crucial for elucidating the mechanisms of post-harvest quality formation during oolong tea processing.This study employed an integrated multi...Understanding the molecular responses of tea leaves to mechanical stress is crucial for elucidating the mechanisms of post-harvest quality formation during oolong tea processing.This study employed an integrated multi-omics strategy to characterize the changes and interactions among metabolomic(MB),transcriptomic(TX),and proteomic(PT)profiles in mechanically stressed tea leaves.Mechanical stress initially activated damage-associated molecular patterns(DAMPs),including Ca^(2+)signaling,jasmonic acid signaling,and glutathione metabolism pathways.These processes subsequently induced quality-related metabolic pathways(QRMPs),particularly α-linolenic acid and phenylalanine metabolism.Upregulated expression of LOX,ADH1,and PAR genes,together with the increased abundance of their encoded proteins,respectively promoted the accumulation of jasmine lactone,benzyl alcohol,and 2-phenylethanol.These findings indicate that mechanical stress influences the metabolite biosynthesis in tea leaves through coordinated molecular responses.This study provides new insights into the molecular mechanisms underlying tea leaf responses to mechanical stress and a foundation for future investigations into how early molecular events may contribute to post-harvest metabolic changes during oolong tea processing.展开更多
Materials exhibiting broadband nonlinear optical responses are critically important for ultrafast photonics applications,particularly as saturable absorbers(SAs)that facilitate broadband optical pulse generation.In th...Materials exhibiting broadband nonlinear optical responses are critically important for ultrafast photonics applications,particularly as saturable absorbers(SAs)that facilitate broadband optical pulse generation.In this study,tea polyphenolpolyvinyl alcohol(TP-PVA)composite films are synthesized via a polymer embedding method and employed as SAs to initiate ultrafast pulse operation in fiber lasers.The TP-PVA SA film exhibits excellent broadband saturable absorption performance at wavelengths of 1.0μm,1.5μm,and 2.0μm,with modulation depths of 54.21%,41.41%,and 51.16%,respectively.Stable passively mode-locked pulses with pulse widths of 588 fs,419 fs,and 743 fs are generated in Yb-,Er-,and Tm-doped fiber lasers,respectively.This work confirms the effective performance of TP-PVA as a broadband SA,and establishes a foundation for the integration of novel and sustainable materials within ultrafast photonic systems.The approach paves the way for developing compact broadband ultrafast laser systems operating in the near-infrared spectral region.展开更多
Carbon dots(CDs),nanoscale carbon-based particles ubiquitously present in thermally processed foods such as toasted products,exhibit exceptional structural stability even after gastrointestinal digestion,a property th...Carbon dots(CDs),nanoscale carbon-based particles ubiquitously present in thermally processed foods such as toasted products,exhibit exceptional structural stability even after gastrointestinal digestion,a property that facilitates their systemic absorption and bioaccumulation.Their persistence in biological systems enables direct interactions with small bioactive molecules,potentially modulating the functional properties of dietary components.This study systematically evaluates the impact of CDs on the antioxidant efficacy of tea polyphenols(TPs),a class of natural antioxidants widely recognized for their health-promoting effects.The structure,antioxidant capacity,and in vitro cytological effects of the CDs-TPs complex were also investigated.Our results demonstrate that CDs and TPs form stable complexes mediated by non-covalent interactions,with hydrogen bonding identified as the dominant mechanism–specifically between the phenolic hydroxyl groups of TPs and fluorescent carbon-rich domains on CDs.These interactions induced a concentration-dependent enhancement in fluorescence intensity,with optimal binding efficiency observed at low CDs/TPs molar ratios(1:1 and 10:1).Structural analyses revealed that TP binding altered the tertiary conformation of CDs,exposing additional luminescent sites and modifying surface charge distribution.Transcriptomic profiling further demonstrated dose-dependent increases in differentially expressed genes under higher CDs/TPs ratios,which were predominantly enriched in oxidative stress response pathways.Mechanistic studies identified the FoxO signaling pathway as a central regulatory axis,with CDs-TPs complexes modulating the expression of antioxidant-related genes(e.g.,SOD2)and downstream effectors involved in redox homeostasis.These findings not only elucidate the structure-function interplay governing CDs-TPs interactions,but also highlight their dual role as modulators of antioxidant activity and potential therapeutic agents,establishing a foundation for developing CD-based composite materials in targeted antioxidant therapies.展开更多
Tea plant(Camellia sinensis(L.)O.Kuntze)is a cold-sensitive leaf-harvesting crop whose growth,yield,and processed tea quality are all inhibited by low temperatures.Therefore,identifying the regulatory genes involved i...Tea plant(Camellia sinensis(L.)O.Kuntze)is a cold-sensitive leaf-harvesting crop whose growth,yield,and processed tea quality are all inhibited by low temperatures.Therefore,identifying the regulatory genes involved in tea plant growth and freezing tolerance is crucial for genetic improvement.WRKY transcription factors regulate various plant processes,including growth and development,stress responses,and metabolite biosynthesis.However,the molecular network through which WRKY coordinates these pathways in tea plants remains unclear.In this study,we revealed that CsWRKY57L,a cold-inducible WRKY IIc subfamily member,positively regulated freezing tolerance by directly promoting flavonoid accumulation in tea plants.Transient suppression of CsWRKY57L weakened the freezing tolerance of tea plants by reducing flavonoid content and suppressing the C-repeat-binding factor(CBF)-cold-responsive(COR)gene pathway.In contrast,heterologous overexpression of CsWRKY57L in Arabidopsis had the opposite effect.Additionally,overexpression of CsWRKY57L inhibited reproductive development and accelerated senescence in Arabidopsis.Interaction analysis revealed that CsWRKY57L directly binds to the promoters of CsSWEET1a,CsSWEET15,and AtSWEET15,which encode sugar transporters essential for plant reproductive development,and inhibits their transcription.Overall,the study revealed a dual role of CsWRKY57L in promoting freezing tolerance via flavonoid biosynthesis and inhibiting reproductive development by regulating SWEETs expression.This study uncovers a novel mechanism whereby CsWRKY57L coordinately regulates both stress responses and growth in tea plants,providing a molecular basis for breeding low-temperature-tolerant varieties with restricted reproductive development.展开更多
Heat stress reduces theanine content in tea plants,but the underlying molecular mechanism remains unclear.In this study,a temperature gradient treatment(20℃,25℃,30℃,and 35℃)was performed to unveil the effect of he...Heat stress reduces theanine content in tea plants,but the underlying molecular mechanism remains unclear.In this study,a temperature gradient treatment(20℃,25℃,30℃,and 35℃)was performed to unveil the effect of heat stress on biosynthesis and accumulation of theanine.We found that heat stress induced metabolic changes,characterized by decreased theanine content and increased catechin levels.In addition,heat stress up-regulated the expression of the class B heat shock transcription factor gene CsHSFB2c,while significantly suppressing the transcription of key theanine biosynthetic genes CsTS1 and CsGS1.Functional studies showed that silencing CsHSFB2c increased theanine content,while its overexpression significantly decreased theanine levels.Consistent with these changes,silencing CsHSFB2c upregulated the expression of CsTS1 and CsGS1,while overexpression of CsHSFB2c downregulated their expression.Yeast one-hybrid(Y1H)and dual-luciferase reporter gene(Dual-LUC)assays showed that CsHSFB2c directly binds to the promoters of CsTS1 and CsGS1 and inhibits their expression.These results demonstrate that CsHSFB2c mediates heat-induced suppression of theanine biosynthesis by directly inhibiting the expression of CsTS1 and CsGS1.This study provides a theoretical basis for improving the heat resistance and quality of tea plants via molecular breeding.展开更多
[Objective] The aim of this study was to select a tea variety with full aro- ma and high quality. [Method] The quality of Yunchachunhao was identified using Yunkang 10 and Fudingdabaicha as the controls in variety com...[Objective] The aim of this study was to select a tea variety with full aro- ma and high quality. [Method] The quality of Yunchachunhao was identified using Yunkang 10 and Fudingdabaicha as the controls in variety comparison test, using Yunkang 10 and Dangdidayezhong as the controls in reginal test. [Result] In variety comparison test, the yield of Yunchachunhao was 39.3% more than that of Yunkang 10, and 29.6% more than that of Fudingdabaicha. In reginal test, the yield of Yun- chachunhao was 2.5% （Baoshan） and 10.2% （Lancang） more than that of Yunkang 10. The roast-dried green tea of Yunchachunhao was characterized by flowery fla- vor, good taste and bright green infused leaves. It got the total scores of 91.13 in quality identification, which was higher than that of Fudingdabaicha （90.75） and Yunkang 10 （88.85）. The steam fixed green tea of Yunchachunhao contained 28.0% polyphenols and 2.7% amino acids; and the ratio of polyphenols to amino acids was 10.4, lower than that of Fudingdabaicha （10.6） and Yunkang 10 （17.3）. Yun- chachunhao had better resistance to drought and blister blight than Yunkang 10. [Conclusion] The survival rates of cuttings and transplanted seedlings of Yun- chachunhao are higher than that of control varieties, suggesting it has better adapt- ability and can be promoted in the large-leaf tea planting area of Yunnan Province.展开更多
Vine tea has been used as an herbal tea by several ethnic minorities for hundreds of years in China.Flavonoids,a kind of indispensable component in a variety of nutraceutical,pharmaceutical and cosmetic applications,a...Vine tea has been used as an herbal tea by several ethnic minorities for hundreds of years in China.Flavonoids,a kind of indispensable component in a variety of nutraceutical,pharmaceutical and cosmetic applications,are identified to be the major metabolites and bioactive ingredients in vine tea.Interestingly,vine tea exhibits a wide range of significant bioactivities including anti-oxidant,anti-inflammatory,anti-tumor,antidiabetic,neuroprotective and other activities,but no toxicity.These bioactivities,to some extent,enrich the understanding about the role of vine tea in disease prevention and therapy.The health benefits of vine tea,particularly dihydromyricetin and myricetin,are widely investigated.However,there is currently no comprehensive review available on vine tea.Therefore,this report summarizes the most recent studies investigating bioactive constituents,pharmacological effects and possible mechanisms of vine tea,which will provide a better understanding about the health benefits and preclinical assessment of novel application of vine tea.展开更多
An experiment was carried out to study the transport process of nitrogen （N） assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15^N-NO3 and 15^N-NH4 were fed to the ...An experiment was carried out to study the transport process of nitrogen （N） assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15^N-NO3 and 15^N-NH4 were fed to the root of tea plants （Camellia sinensis L.）. Results showed that the main amino acids were glutamine, theanine, axginine, asparic acid and glutamic acid, which accounted for 49%, 17%, 8%, 7%, and 4%, respectively, of the total amino acids in the xylem sap. After the tea plants were fed with 15^N-NO3 and 15^N-NH4 for 48 h, the amount of total amino acids in xylem sap significantly increased and those fed with 15^N-NH4 had higher increment than those with 15^N-NOa. Two hours after 15^N- NO3 and 15^N-NH4 were fed, 15N abundance in glutamine, asparagine, glutamic acid, alanine, and arginine were detected and increased quickly over time. This indicated that it took less than 2 h for NO3-N and NH4-N to be absorbed by tea roots, incorporated into the above amino acids and transported to the xylem sap. Rapid increase in 15^N-NO3 in the xylem sap of tea plants fed with 15^N-NO3 indicated that nitrate could be directly transported to the xylem sap. Glutamine, theanine, and alanine were the main amino acids transported in xylem sap of tea plants fed with both 15^N-NO3 and 15^N-NH4.展开更多
Lime application is a conventional technology to control acidification in tea orchard soils. We investigated the effect of lime application on soil microbial community diversity in the soils of three tea orchards, was...Lime application is a conventional technology to control acidification in tea orchard soils. We investigated the effect of lime application on soil microbial community diversity in the soils of three tea orchards, wasteland and forest. The BIOLOG data showed that both the average well color development of all carbon sources and the functional diversity index increased with the liming rate in the tea orchards and the forest, but decreased in the wasteland. The phospholipid fatty acid （PLFA） analysis showed that the structural diversity index of soil microbial community increased with the liming rate in all the tea orchards, the wasteland and the forest. Lime application also increased the soil-bacterial PLFA content in all the soils. Soil fungal and actinomycete PLFAs in the tea orchards showed an increasing trend from 0 to 3.2 g CaCO 3 /kg application and then a decreasing trend from 3.2 to 6.4 g CaCO 3 /kg application. The principal component analysis of BIOLOG and PLFA data suggested that lime application had a significant effect on soil microbial community structure, and land use had a greater effect on soil microbial community structure compared to lime application.展开更多
In the postharvest processing of tea leaves,withering is the first indispensable manufacturing process which produces the mellow,umami and sweet taste of white tea.In this study,we aimed to determine the dynamic chang...In the postharvest processing of tea leaves,withering is the first indispensable manufacturing process which produces the mellow,umami and sweet taste of white tea.In this study,we aimed to determine the dynamic changes of the main metabolites and clarify the key differentially expressed genes(DEGs) involved in forming the characteristic taste of white tea during withering.Phytochemical analyses revealed that the contents of total catechins and starch decreased continuously,whereas the contents of theaflavin,γ-aminobutyric acid(GABA),maltose,and soluble sugars increased significantly during withering(from 0–48 h).Meanwhile,the elevation of α-amylase(AMY),β-amylase(BAM),total amylase,and glutamate decarboxylase(GAD) activities may be correlated with the accumulation of GABA and maltose.By transcriptome sequencing,we detected 9 707,15 921,17 353,and 17 538 DEGs at 12,24,36,and 48 h of the withering process,respectively,compared with 0 h sample(fresh leaves).The transcript levels of most of the DEGs involved in catechin biosynthesis were significantly inhibited,whereas those involved in catechin oxidation were significantly up-regulated,which could be correlated to a decrease in catechin content and an increase in theaflavin content.The DEGs involved in GABA biosynthesis were considerably up-regulated,and the down-regulation of SPMS could reduce the competition for converting spermidine to GABA.The up-regulation of the AMY and BAM genes could trigger starch degradation,resulting in the increase of soluble sugar content.These results provide new insights into the importance of the withering process to the characteristic taste of white tea.展开更多
Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry...Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) was developed to simultaneously determine 11 amino acids in different types of tea (green teas, Oolong tea, black tea and Pu-erh tea). The separation conditions for the analysis of the selected amino acids including the column type, temperature and backpressure as well as the type of additive, were carefully optimized. The best separation of the 11 amino acids was obtained by adding water (5%, v/v) and trifluoroacetic acid (0.4%, v/v) to the organic modifier (methanol). Finally, the developed SFC-MS method was fully validated and successfully applied to the determination of these amino acids in six different tea samples. Good linearity (r ≥ 0.993), precision (RSDs≤ 2.99%), accuracy (91.95%-107.09%) as well as good sample stability were observed. The limits of detection ranged from 1.42 to 14.69 ng/mL, while the limits of quantification were between 4.53 and 47.0 ng/mL. The results indicate that the contents of the 11 amino acids in the six different tea samples are greatly influenced by the degree of fermentation. The proposed SFC-MS method shows a great potential for further investigation of tea varieties.展开更多
AIM： To investigate the hepatoprotective activity of tea polyphenols （TP） and its relation with cytochrome P450 （CYP450） expression in mice. METHODS： Hepatic CYP450 and CYPbs levels were measured by UV-spectroph...AIM： To investigate the hepatoprotective activity of tea polyphenols （TP） and its relation with cytochrome P450 （CYP450） expression in mice. METHODS： Hepatic CYP450 and CYPbs levels were measured by UV-spectrophotometry in mice 2 d after intraperitoneal TP （25, 50 and 100 mg/kg per day）. Then the mice were intragastricly pre-treated with TP （100, 200 and 400 mg/kg per day） for six days before paracetamol （1000 mg/kg） was given. Their acute mortality was compared with that of control mice. The mice were pre-treated with TP （100, 200, and 400 mg/kg per day） for five days before paracetamol （500 mg/kg） was given. Hepatic CYP2E1 and CYPIA2 protein and mRNA expression levels were evaluated by Western blotting, immunohistochemical staining and transcriptase-polymerase chain reaction. RESULTS： The hepatic CYP450 and CYPb5 levels in mice of TP-treated groups （100, 200 and 400 mg/kg per day） were decreased in a dose-dependent manner compared with those in the negative control mice.TP significantly attenuated the paracetamol-induced hepatic injury and dramatically reduced the mortality of paracetamol-treated mice. Furthermore, TP reduced CYP2E1 and CYPIA2 expression at both protein and mRNA levels in a dose-dependent manner. CONCLUSION： TP possess potential hepatoprotective properties and can suppress CYP450 expression.展开更多
Pu-erh ripen tea becomes popular worldwide owing to its unique taste and aroma.In the present study,volatile compounds from Pu-erh ripen tea were extracted using a solvent assisted flavor evaporation(SAFE)and analyzed...Pu-erh ripen tea becomes popular worldwide owing to its unique taste and aroma.In the present study,volatile compounds from Pu-erh ripen tea were extracted using a solvent assisted flavor evaporation(SAFE)and analyzed with a gas chromatography-mass spectrometry(GC-MS)and a gas chromatography olfactometry(GC-O).Results demonstrated that 58 major volatile compounds and 24 aroma active substances of Pu-erh ripen tea were identified by GC-MS and GC-O analysis.Among volatile compounds identified,methoxyphenyl compounds were considered as the dominate compounds in the aroma of Pu-erh ripen tea.Further investigation showed that 6 methoxybenzenes were responsible for the aging aroma in Pu-erh ripen tea;α-ionone,3,4-dimethoxytoluene,1,3-dimethoxybenzene,etc.were responsible for the wood-like aroma.Linalool,α-terpineol,α-ionone,β-ionone,and benzeneacetaldehyde were responsible for the floral odor.Compared the odor detection threshold(ODT)among the 8 methoxyphenyl compounds in water,1,2,3-trimethoxybenzene showed the highest ODT,followed by 3,4-dimethoxyphenol.1,3-dimethoxybenzene(105μg/L)and 1,2,3-trimethoxy-5-methylbenzene(100μg/L)were present at relatively low odor threshold values.The result indicated that methoxyphenyl compounds play a vital role in the unique flavor of Pu-erh ripen tea.展开更多
文摘On the stone-paved lanes of Songyang County that date back to ancient times,morning mist lingered as a faint fragrance of tea wafted from a century-old house.Inside,Yang Junjie,a tea maker born in the 1980s,worked deftly at the stove,his hands moving swiftly over the scorching iron wok as tender green tea leaves dance between his fingers.
文摘In May 2025,the Fuding White Tea Culture System in southeast China’s Fujian Province was officially recognized by the UN Food and Agriculture Organization(FAO)as a Globally Important Agricultural Heritage System(GIAHS).It mainly includes national-level superior varieties-Fuding Dabai Tea,Fuding Dahao Tea,and Fuding Cai Tea(group variety)which retains tradition and uses tea seeds for sexual reproduction-providing abundant germplasm resources for cultivating new tea varieties.
基金Ho Chi Minh City University of Technology(HCMUT),VNU-HCM for supporting this study.
文摘Vitamin C,a potent antioxidant with broad therapeutic applications,is limited by rapid degradation under environmental stressors,which compromises its stability and bioactivity.This study addresses these limitations by formulating a double nano-emulsion(W/O/W)system incorporating macadamia oil and tea tree oil,using homogenization and phase inversion temperature(PIT)techniques.Comprehensive physicochemical charac-terization,including droplet size,polydispersity index(PDI),zeta potential,turbidity,Fourier transform infrared spectroscopy(FTIR),and SEM,was conducted alongside stability assessments under varying pH,temperature,and storage conditions.The optimized nano-emulsions exhibited nanoscale droplet sizes(10-40 nm),low PDI values(indicating high uniformity),and robust stability.Interestingly,the formulation with 2%W/O loading,with a particle size of 11.57 nm and a PDI of 0.04,demonstrated an antioxidant capacity of 4622.62μg ascorbic acid equivalents(AA)/g,which was significantly higher(p<0.05)compared to both natural oils(macadamia oil:20.91μg AA/g,tea tree oil:16.86μg AA/g)and a 10%Vitamin C aqueous solution(592.94μg AA/g).FTIR analysis confirmed the molecular integrity of Vitamin C and its successful encapsulation with macadamia and tea tree oils,while SEM images revealed uniformly spherical and well-dispersed droplets.Moreover,the formulation retained its structural integrity and antioxidant functionality under diverse pH and thermal conditions.These findings underscore the potential of double nano-emulsion systems to overcome the stability challenges of Vitamin C,offering a promising approach to enhance its bioavailability and therapeutic performance in phar-maceutical and cosmetic applications.
基金financially supported by Jiangxi University of Chinese Medicine School-level Science and Technology Innovation Team Development Program(No.CXTD22005)PhD research startup fund of Jiangxi University of Chinese Medicine(No.2023BSZR005)。
文摘Selenium is one of the important trace elements in the human body.Its deficiency will directly affect human health.With people's attention to health,the content of selenium in food has gradually attracted attention.However,detecting selenium compounds in complex samples remains a challenge.In this work,we built an online heating-reaction device.This device combines the electrospray extraction ionization mass spectrometry(EESI-MS)with the heating reaction device,which can simultaneously detect various selenium compounds in complex liquid samples.Under acidic conditions,the sample was heated and catalyzed by a heating reaction device,so that the SeO~(2-)_(3)and O-phenylenediamine(OPD)could generate 1,3-dihydro-2,1,3-benzoselenadiazole.Based on the above reactions,we can detect organic selenium,inorganic selenium and other compounds in liquid samples by organic mass spectrometry.In this experiment,we determined the content of three forms of selenium:selenomethionine(SeMet),l-selenocystine(SeCys(2)),and sodium selenite.The calibration curves for SeMet,SeCys(2),and sodium selenite showed strong linearity within a range of 0.50-50.00μg/L.The limits of detection(LOD)for the three compounds were 0.22,0.27,and 0.41μg/L,respectively.The limits of quantification(LOQ)were 0.68,0.81,and 1.23μg/L,respectively.Spiked recoveries at three levels ranged from 98.8%to 106.1%.In addition,this method can simultaneously detect three selenium compounds and three other specific chemical components in tea infusion samples,providing a rapid and efficient method for identifying tea quality.
基金financially supported by the National Key Research and Development Program of China(2022YFD1600803)the National Natural Science Foundation of China(31772077)+1 种基金the Yunnan Provincial Tea Industry Technology Innovation Center,China(202505AK340010)the Chinese Academy of Agricultural Sciences for Agricultural Science and Technology Innovation Program of Tea Research Institute(CAAS-ASTIP-2021-TRI)。
文摘China has limited acaricide options for tea plantations.Cyetpyrafen,a novel domestic acaricide with high efficacy,low toxicity and a negative temperature coefficient,offers an alternative for tea pest control;however,its residue fate in tea remains unclear.This study developed a method to simultaneously detect cyetpyrafen and its metabolites(M-309,M-325-1,and M-409-3)in different tea matrices to investigate their fate.Recoveries of compounds ranged from 73.4 to 106.2%with the relative standard deviations(RSDs)below 12.0%.During tea cultivation,the dissipation half-life of cyetpyrafen was 0.59 d,with M-309 as a major metabolite.The residues of cyetpyrafen and M-309 were affected by different processing stages,especially water loss and high temperatures during fixing,drying and withering.The total processing factors ranged from 1.39 to 1.71 for green tea and 1.48 to 2.28 for black tea(processed from fresh tea leaves sampled at 1,5,and 7 d),respectively.The leaching rates of cyetpyrafen from green tea and black tea into tea infusions were 7.4 and 6%,respectively.The risk associated with cyetpyrafen intake from tea consumption was low,with risk quotient values below 100%.However,theoretical calculation indicated potential harm to non-target organisms from its metabolites.This research provides a reference for the safe and efficient use of cyetpyrafen in tea gardens.
基金supported by Project of Zhangjiajie City’s Industry-Academia-Research Collaborative Innovation‘Open Project Leader’,Zhangjiajie City’s Project of Taking on Challenging Tasks by Responding to Calls for Solutions(JB20230530)Basic Research Funds Project for Central Universities of China(2023XCZX001,2020kfyXJJS120)Academician and Expert Workstations in Yunnan Province(202205AF150090).
文摘Vine tea is documented in ancient Chinese books as having the function of promoting blood circulation.However,its effects and mechanisms remain unclear.The aim of this study was to comprehensively investigate the protective potential and mechanisms of vine tea in high-fat diet rat through a combination of in vivo and in vitro experiments.The efficacy of vine tea was evaluated using a high-fat diet rat model and an oxidized low-density lipoprotein-treated cell model,with physiological and biochemical indicators measured in rat serum and cell supernatants.Transcriptomics was utilized to investigate alterations mRNA expression following the administration of dihydromyricetin in cell model.Metabolomics and 16S rRNA sequencing was employed to examine changes in metabolites in the serum and changes in gut microbiota of high-fat diet rats after administering vine tea extract.Vine tea extract and dihydromyricetin can reduce elevated levels of lipids,including total cholesterol and triglycerides,following modeling.Transcriptomic data indicate that dihydromyricetin exerts its effects by regulating ferroptosis signaling pathways.Metabolomic analysis demonstrates that the administration of vine tea extract influences the vitamin K cycle and glutathione,thereby alleviating the progression of ferroptosis.Additionally,16S rRNA sequencing reveals that vine tea extract increases Lactobacillaceae in the gut microbiota,which subsequently affects the levels of lysophosphatidylcholine,a major phospholipid component of oxidized low-density lipoprotein in serum.Our results indicate that vine tea can regulate ferroptosis signaling pathways and increase Lactobacillaceae in the gut microbiota,thereby exhibiting cardiovascular protective effects in high-fat diet rats.
基金supported by the National Key Research and Development Program of China(2022YFD2101101)the Earmarked Fund for CARS-19+2 种基金the National Natural Science Foundation of China(32402634)the Modern Agricultural(Tea)Industry Technology System of Fujian Province,China(2025 No.593)the Special Fund for Science and Technology Innovation of Fujian Zhang Tianfu Tea Development Foundation,China(FJZTF01)。
文摘Understanding the molecular responses of tea leaves to mechanical stress is crucial for elucidating the mechanisms of post-harvest quality formation during oolong tea processing.This study employed an integrated multi-omics strategy to characterize the changes and interactions among metabolomic(MB),transcriptomic(TX),and proteomic(PT)profiles in mechanically stressed tea leaves.Mechanical stress initially activated damage-associated molecular patterns(DAMPs),including Ca^(2+)signaling,jasmonic acid signaling,and glutathione metabolism pathways.These processes subsequently induced quality-related metabolic pathways(QRMPs),particularly α-linolenic acid and phenylalanine metabolism.Upregulated expression of LOX,ADH1,and PAR genes,together with the increased abundance of their encoded proteins,respectively promoted the accumulation of jasmine lactone,benzyl alcohol,and 2-phenylethanol.These findings indicate that mechanical stress influences the metabolite biosynthesis in tea leaves through coordinated molecular responses.This study provides new insights into the molecular mechanisms underlying tea leaf responses to mechanical stress and a foundation for future investigations into how early molecular events may contribute to post-harvest metabolic changes during oolong tea processing.
基金supported by the Opening Foundation of Hubei Key Laboratory for New Textile Materials and Applications Research(Grant No.FZXCL202410)the Key Project of Science and Technology Research Program of Hubei Provincial Department of Education,China(Grant No.D20231704)+1 种基金Wuhan Textile University(Grant No.523058)the Foundation of Wuhan Textile University(Grant No.K24058)。
文摘Materials exhibiting broadband nonlinear optical responses are critically important for ultrafast photonics applications,particularly as saturable absorbers(SAs)that facilitate broadband optical pulse generation.In this study,tea polyphenolpolyvinyl alcohol(TP-PVA)composite films are synthesized via a polymer embedding method and employed as SAs to initiate ultrafast pulse operation in fiber lasers.The TP-PVA SA film exhibits excellent broadband saturable absorption performance at wavelengths of 1.0μm,1.5μm,and 2.0μm,with modulation depths of 54.21%,41.41%,and 51.16%,respectively.Stable passively mode-locked pulses with pulse widths of 588 fs,419 fs,and 743 fs are generated in Yb-,Er-,and Tm-doped fiber lasers,respectively.This work confirms the effective performance of TP-PVA as a broadband SA,and establishes a foundation for the integration of novel and sustainable materials within ultrafast photonic systems.The approach paves the way for developing compact broadband ultrafast laser systems operating in the near-infrared spectral region.
基金supported by the National Key Research and Development Program of China(No.2024 YFD2401602)the National Natural Science Foundation of China(No.32302209)+4 种基金the Natural Science Foundation of Zhejiang Province(No.LQ24C200001)the Young Science and Technology Innovation Leading Talents of Ningbo City(No.2023QL038)the Natural Science Foundation of Ningbo(No.2023J104)the Zhejiang Provincial Department of Education General Project(Nos.Y202248913,Y202248913)the General Project of Education Department of Zhejiang Province(No.Y202353405)。
文摘Carbon dots(CDs),nanoscale carbon-based particles ubiquitously present in thermally processed foods such as toasted products,exhibit exceptional structural stability even after gastrointestinal digestion,a property that facilitates their systemic absorption and bioaccumulation.Their persistence in biological systems enables direct interactions with small bioactive molecules,potentially modulating the functional properties of dietary components.This study systematically evaluates the impact of CDs on the antioxidant efficacy of tea polyphenols(TPs),a class of natural antioxidants widely recognized for their health-promoting effects.The structure,antioxidant capacity,and in vitro cytological effects of the CDs-TPs complex were also investigated.Our results demonstrate that CDs and TPs form stable complexes mediated by non-covalent interactions,with hydrogen bonding identified as the dominant mechanism–specifically between the phenolic hydroxyl groups of TPs and fluorescent carbon-rich domains on CDs.These interactions induced a concentration-dependent enhancement in fluorescence intensity,with optimal binding efficiency observed at low CDs/TPs molar ratios(1:1 and 10:1).Structural analyses revealed that TP binding altered the tertiary conformation of CDs,exposing additional luminescent sites and modifying surface charge distribution.Transcriptomic profiling further demonstrated dose-dependent increases in differentially expressed genes under higher CDs/TPs ratios,which were predominantly enriched in oxidative stress response pathways.Mechanistic studies identified the FoxO signaling pathway as a central regulatory axis,with CDs-TPs complexes modulating the expression of antioxidant-related genes(e.g.,SOD2)and downstream effectors involved in redox homeostasis.These findings not only elucidate the structure-function interplay governing CDs-TPs interactions,but also highlight their dual role as modulators of antioxidant activity and potential therapeutic agents,establishing a foundation for developing CD-based composite materials in targeted antioxidant therapies.
基金supported by the National Natural Science Foundation of China(Grant Nos.32072630,32372774,and U22A20499)the earmarked fund for CARS(Grant No.CARS-19-01A).
文摘Tea plant(Camellia sinensis(L.)O.Kuntze)is a cold-sensitive leaf-harvesting crop whose growth,yield,and processed tea quality are all inhibited by low temperatures.Therefore,identifying the regulatory genes involved in tea plant growth and freezing tolerance is crucial for genetic improvement.WRKY transcription factors regulate various plant processes,including growth and development,stress responses,and metabolite biosynthesis.However,the molecular network through which WRKY coordinates these pathways in tea plants remains unclear.In this study,we revealed that CsWRKY57L,a cold-inducible WRKY IIc subfamily member,positively regulated freezing tolerance by directly promoting flavonoid accumulation in tea plants.Transient suppression of CsWRKY57L weakened the freezing tolerance of tea plants by reducing flavonoid content and suppressing the C-repeat-binding factor(CBF)-cold-responsive(COR)gene pathway.In contrast,heterologous overexpression of CsWRKY57L in Arabidopsis had the opposite effect.Additionally,overexpression of CsWRKY57L inhibited reproductive development and accelerated senescence in Arabidopsis.Interaction analysis revealed that CsWRKY57L directly binds to the promoters of CsSWEET1a,CsSWEET15,and AtSWEET15,which encode sugar transporters essential for plant reproductive development,and inhibits their transcription.Overall,the study revealed a dual role of CsWRKY57L in promoting freezing tolerance via flavonoid biosynthesis and inhibiting reproductive development by regulating SWEETs expression.This study uncovers a novel mechanism whereby CsWRKY57L coordinately regulates both stress responses and growth in tea plants,providing a molecular basis for breeding low-temperature-tolerant varieties with restricted reproductive development.
基金supported by the Major Project of Guizhou Provincial Science and Technology Program,China([2024]027)the High-Level Innovative Talents Project of Guizhou Province,China(GCC[2023]014)+1 种基金the Guizhou Provincial Tea Industry Technology System,China(GZCYCYJSTX-03)the Science and Technology Project of China Huaneng Group(HNKJ2022-H135)。
文摘Heat stress reduces theanine content in tea plants,but the underlying molecular mechanism remains unclear.In this study,a temperature gradient treatment(20℃,25℃,30℃,and 35℃)was performed to unveil the effect of heat stress on biosynthesis and accumulation of theanine.We found that heat stress induced metabolic changes,characterized by decreased theanine content and increased catechin levels.In addition,heat stress up-regulated the expression of the class B heat shock transcription factor gene CsHSFB2c,while significantly suppressing the transcription of key theanine biosynthetic genes CsTS1 and CsGS1.Functional studies showed that silencing CsHSFB2c increased theanine content,while its overexpression significantly decreased theanine levels.Consistent with these changes,silencing CsHSFB2c upregulated the expression of CsTS1 and CsGS1,while overexpression of CsHSFB2c downregulated their expression.Yeast one-hybrid(Y1H)and dual-luciferase reporter gene(Dual-LUC)assays showed that CsHSFB2c directly binds to the promoters of CsTS1 and CsGS1 and inhibits their expression.These results demonstrate that CsHSFB2c mediates heat-induced suppression of theanine biosynthesis by directly inhibiting the expression of CsTS1 and CsGS1.This study provides a theoretical basis for improving the heat resistance and quality of tea plants via molecular breeding.
基金Supported by Science and Technology Plan of Yunnan Province(2010BB012)National Key Technology Research and Development Program(2011BAD01B01)~~
文摘[Objective] The aim of this study was to select a tea variety with full aro- ma and high quality. [Method] The quality of Yunchachunhao was identified using Yunkang 10 and Fudingdabaicha as the controls in variety comparison test, using Yunkang 10 and Dangdidayezhong as the controls in reginal test. [Result] In variety comparison test, the yield of Yunchachunhao was 39.3% more than that of Yunkang 10, and 29.6% more than that of Fudingdabaicha. In reginal test, the yield of Yun- chachunhao was 2.5% （Baoshan） and 10.2% （Lancang） more than that of Yunkang 10. The roast-dried green tea of Yunchachunhao was characterized by flowery fla- vor, good taste and bright green infused leaves. It got the total scores of 91.13 in quality identification, which was higher than that of Fudingdabaicha （90.75） and Yunkang 10 （88.85）. The steam fixed green tea of Yunchachunhao contained 28.0% polyphenols and 2.7% amino acids; and the ratio of polyphenols to amino acids was 10.4, lower than that of Fudingdabaicha （10.6） and Yunkang 10 （17.3）. Yun- chachunhao had better resistance to drought and blister blight than Yunkang 10. [Conclusion] The survival rates of cuttings and transplanted seedlings of Yun- chachunhao are higher than that of control varieties, suggesting it has better adapt- ability and can be promoted in the large-leaf tea planting area of Yunnan Province.
文摘Vine tea has been used as an herbal tea by several ethnic minorities for hundreds of years in China.Flavonoids,a kind of indispensable component in a variety of nutraceutical,pharmaceutical and cosmetic applications,are identified to be the major metabolites and bioactive ingredients in vine tea.Interestingly,vine tea exhibits a wide range of significant bioactivities including anti-oxidant,anti-inflammatory,anti-tumor,antidiabetic,neuroprotective and other activities,but no toxicity.These bioactivities,to some extent,enrich the understanding about the role of vine tea in disease prevention and therapy.The health benefits of vine tea,particularly dihydromyricetin and myricetin,are widely investigated.However,there is currently no comprehensive review available on vine tea.Therefore,this report summarizes the most recent studies investigating bioactive constituents,pharmacological effects and possible mechanisms of vine tea,which will provide a better understanding about the health benefits and preclinical assessment of novel application of vine tea.
文摘An experiment was carried out to study the transport process of nitrogen （N） assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15^N-NO3 and 15^N-NH4 were fed to the root of tea plants （Camellia sinensis L.）. Results showed that the main amino acids were glutamine, theanine, axginine, asparic acid and glutamic acid, which accounted for 49%, 17%, 8%, 7%, and 4%, respectively, of the total amino acids in the xylem sap. After the tea plants were fed with 15^N-NO3 and 15^N-NH4 for 48 h, the amount of total amino acids in xylem sap significantly increased and those fed with 15^N-NH4 had higher increment than those with 15^N-NOa. Two hours after 15^N- NO3 and 15^N-NH4 were fed, 15N abundance in glutamine, asparagine, glutamic acid, alanine, and arginine were detected and increased quickly over time. This indicated that it took less than 2 h for NO3-N and NH4-N to be absorbed by tea roots, incorporated into the above amino acids and transported to the xylem sap. Rapid increase in 15^N-NO3 in the xylem sap of tea plants fed with 15^N-NO3 indicated that nitrate could be directly transported to the xylem sap. Glutamine, theanine, and alanine were the main amino acids transported in xylem sap of tea plants fed with both 15^N-NO3 and 15^N-NH4.
基金supported by the National Natural Science Foundation of China (No. 30671207, 30871600)the Zhejiang Provincial National Science Foundation of China(No. Y5080067)the Doctoral Scientific Research Foundation of Luoyang Institute of Science and Technology (No. 2008BZ04)
文摘Lime application is a conventional technology to control acidification in tea orchard soils. We investigated the effect of lime application on soil microbial community diversity in the soils of three tea orchards, wasteland and forest. The BIOLOG data showed that both the average well color development of all carbon sources and the functional diversity index increased with the liming rate in the tea orchards and the forest, but decreased in the wasteland. The phospholipid fatty acid （PLFA） analysis showed that the structural diversity index of soil microbial community increased with the liming rate in all the tea orchards, the wasteland and the forest. Lime application also increased the soil-bacterial PLFA content in all the soils. Soil fungal and actinomycete PLFAs in the tea orchards showed an increasing trend from 0 to 3.2 g CaCO 3 /kg application and then a decreasing trend from 3.2 to 6.4 g CaCO 3 /kg application. The principal component analysis of BIOLOG and PLFA data suggested that lime application had a significant effect on soil microbial community structure, and land use had a greater effect on soil microbial community structure compared to lime application.
基金supported by the China Agriculture Research System of MOF and MARA (CARS-19)the Scientific Research Foundation of Graduate School of Fujian Agriculture and Forestry University, China (102–1122YS010)+6 种基金the Rural Revitalization Tea Industry Technical Service Project of Fujian Agriculture and Forestry University, China (11899170145)the “Double First-class” Scientific and Technological Innovation Capacity and Enhancement Cultivation Plan of Fujian Agriculture and Forestry University, China (KSYLP004)6.18 Tea Industry Technology Branch of Collaborative Innovation Institute, China (K1520001A)the Fujian Agriculture and Forestry University Construction Project for Technological Innovation and Service System of Tea Industry Chain, China (K1520005A01)the Construction of Plateau Discipline of Fujian Province, China (102/71201801101)the Biochemical Analysis and Biological Study of Tea Plant Germplasm Resources of Fujian Agriculture and Forestry University, China (K1518023A)the Innovation Training Program for College Students of Fujian Agriculture and Forestry University, China (102–111ZC20061)。
文摘In the postharvest processing of tea leaves,withering is the first indispensable manufacturing process which produces the mellow,umami and sweet taste of white tea.In this study,we aimed to determine the dynamic changes of the main metabolites and clarify the key differentially expressed genes(DEGs) involved in forming the characteristic taste of white tea during withering.Phytochemical analyses revealed that the contents of total catechins and starch decreased continuously,whereas the contents of theaflavin,γ-aminobutyric acid(GABA),maltose,and soluble sugars increased significantly during withering(from 0–48 h).Meanwhile,the elevation of α-amylase(AMY),β-amylase(BAM),total amylase,and glutamate decarboxylase(GAD) activities may be correlated with the accumulation of GABA and maltose.By transcriptome sequencing,we detected 9 707,15 921,17 353,and 17 538 DEGs at 12,24,36,and 48 h of the withering process,respectively,compared with 0 h sample(fresh leaves).The transcript levels of most of the DEGs involved in catechin biosynthesis were significantly inhibited,whereas those involved in catechin oxidation were significantly up-regulated,which could be correlated to a decrease in catechin content and an increase in theaflavin content.The DEGs involved in GABA biosynthesis were considerably up-regulated,and the down-regulation of SPMS could reduce the competition for converting spermidine to GABA.The up-regulation of the AMY and BAM genes could trigger starch degradation,resulting in the increase of soluble sugar content.These results provide new insights into the importance of the withering process to the characteristic taste of white tea.
基金the financial support from China Postdoctoral Science Foundation(2018M643205)
文摘Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) was developed to simultaneously determine 11 amino acids in different types of tea (green teas, Oolong tea, black tea and Pu-erh tea). The separation conditions for the analysis of the selected amino acids including the column type, temperature and backpressure as well as the type of additive, were carefully optimized. The best separation of the 11 amino acids was obtained by adding water (5%, v/v) and trifluoroacetic acid (0.4%, v/v) to the organic modifier (methanol). Finally, the developed SFC-MS method was fully validated and successfully applied to the determination of these amino acids in six different tea samples. Good linearity (r ≥ 0.993), precision (RSDs≤ 2.99%), accuracy (91.95%-107.09%) as well as good sample stability were observed. The limits of detection ranged from 1.42 to 14.69 ng/mL, while the limits of quantification were between 4.53 and 47.0 ng/mL. The results indicate that the contents of the 11 amino acids in the six different tea samples are greatly influenced by the degree of fermentation. The proposed SFC-MS method shows a great potential for further investigation of tea varieties.
基金Grant from the Science Foundation of Educational Department of Liaoning Province,05L117Dalian Science&Technology Bureau,2007J22JH012
文摘AIM： To investigate the hepatoprotective activity of tea polyphenols （TP） and its relation with cytochrome P450 （CYP450） expression in mice. METHODS： Hepatic CYP450 and CYPbs levels were measured by UV-spectrophotometry in mice 2 d after intraperitoneal TP （25, 50 and 100 mg/kg per day）. Then the mice were intragastricly pre-treated with TP （100, 200 and 400 mg/kg per day） for six days before paracetamol （1000 mg/kg） was given. Their acute mortality was compared with that of control mice. The mice were pre-treated with TP （100, 200, and 400 mg/kg per day） for five days before paracetamol （500 mg/kg） was given. Hepatic CYP2E1 and CYPIA2 protein and mRNA expression levels were evaluated by Western blotting, immunohistochemical staining and transcriptase-polymerase chain reaction. RESULTS： The hepatic CYP450 and CYPb5 levels in mice of TP-treated groups （100, 200 and 400 mg/kg per day） were decreased in a dose-dependent manner compared with those in the negative control mice.TP significantly attenuated the paracetamol-induced hepatic injury and dramatically reduced the mortality of paracetamol-treated mice. Furthermore, TP reduced CYP2E1 and CYPIA2 expression at both protein and mRNA levels in a dose-dependent manner. CONCLUSION： TP possess potential hepatoprotective properties and can suppress CYP450 expression.
基金supported by grants from the Chongqing Municipal Agriculture Committee(2020-7)。
文摘Pu-erh ripen tea becomes popular worldwide owing to its unique taste and aroma.In the present study,volatile compounds from Pu-erh ripen tea were extracted using a solvent assisted flavor evaporation(SAFE)and analyzed with a gas chromatography-mass spectrometry(GC-MS)and a gas chromatography olfactometry(GC-O).Results demonstrated that 58 major volatile compounds and 24 aroma active substances of Pu-erh ripen tea were identified by GC-MS and GC-O analysis.Among volatile compounds identified,methoxyphenyl compounds were considered as the dominate compounds in the aroma of Pu-erh ripen tea.Further investigation showed that 6 methoxybenzenes were responsible for the aging aroma in Pu-erh ripen tea;α-ionone,3,4-dimethoxytoluene,1,3-dimethoxybenzene,etc.were responsible for the wood-like aroma.Linalool,α-terpineol,α-ionone,β-ionone,and benzeneacetaldehyde were responsible for the floral odor.Compared the odor detection threshold(ODT)among the 8 methoxyphenyl compounds in water,1,2,3-trimethoxybenzene showed the highest ODT,followed by 3,4-dimethoxyphenol.1,3-dimethoxybenzene(105μg/L)and 1,2,3-trimethoxy-5-methylbenzene(100μg/L)were present at relatively low odor threshold values.The result indicated that methoxyphenyl compounds play a vital role in the unique flavor of Pu-erh ripen tea.
