Carbonic anhydrase 2 mediates anti-obesity effects of black tea as thermogenic activator

Obesity is a metabolic disorder due to over-accumulation of adipose tissue and ultimately becomes a“disease”.Brown adipose tissue(BAT)thermogenesis and white adipose tissue(WAT)browning emerge as a potential strategy of anti-obesity by dissipating energy as heat.However,drugs based on adipose tissue thermogenesis have not been successfully approved yet.In current study,we found that black tea extract(BTE)obtained by patentauthorized manufacturing process prevented body weight gain as novel thermogenic activator with reduction of adiposity,improvement of adipose distribution,and glucose metabolism improvement in diet-induced obesity mice.Mechanismly,anti-obesity effect of BTE depends on promoting BAT thermogenesis and WAT browning with upregulation of uncoupling protein 1(UCP1),especially visceral adipose tissue(VAT)with browning resistance.Specifically,utilizing in silico approach of network pharmacology and molecular docking,we identified carbonic anhydrase 2(CA2)in nitrogen metabolism as anti-obesity target of BTE and further elucidated that protein kinase B(AKT)signaling pathway linked CA2 and UCP1.Meanwhile gut microbiota regulation may prompt the CA2-dependent thermogenesis activation.Our findings demonstrated anti-obesity effect of BTE as thermogenic activator through CA2-mediated BAT thermogenesis and WAT browning via CA2-AKT-UCP1 signaling pathway,which could be developed as promising anti-obesity agent with good safety and efficacy.

Optimization of Supercritical Extraction Process of Laoshan Black Tea by Response Surface Methodology

[Objectives]Laoshan black tea was subjected to supercritical CO_(2) extraction. [Methods]The extraction conditions of Laoshan black tea were studied by an orthogonal experiment and optimized by response surface methodology. [Results] The optimum extraction conditions of black tea extract by supercritical CO_(2) extraction were as follows: extraction pressure 23.53 MPa, extraction time 1.73 h, and extraction temperature 49.75 ℃, with which the extract yield could reach 5.15% theoretically. [Conclusions] Based on the traditional extraction process, a supercritical extraction method optimized by response surface methodology and a unique extraction process were formed, which enriches the extraction processes and methods of natural raw materials.

Comparative Study on Functional Properties of Mulberry Black Tea Fermented by Phellinus igniarius and Eurotium cristatum

[Objectives]To compare functional properties of mulberry black tea fermented by Phellinus igniarius and Eurotium cristatum.[Methods]The functional components of mulberry black tea fermented by P.igniarius and E.cristatum,the deep processing and health care effects of two probiotic fungi were explored.[Results]The polysaccharide content in the tea fermented by P.igniarius was the highest at 0.410 mg/mL,and the hydroxyl radical scavenging rate was the strongest,reaching 60.31%;the content of flavonoids in the tea fermented by E.cristatum was the highest,reaching 60.65μg/mL,and the content of polysaccharides was 83.17%higher than that of mulberry black tea,reaching 0.279 mg/mL.[Conclusions]The mulberry black tea fermented by P.igniarius and E.cristatum has improved in different functional components,and has its own advantages in aroma and mouthfeel,so it has certain research value and market prospect.

Black tea in chemo-prevention of cancer and other human diseases

Tea is the most popular functional beverage in the world and has been gaining more and more attention for its health beneficial properties.Among common teas,black tea is consumed more than green tea and oolong tea worldwide.Numerous studies have shown the biological activities of black tea and its polyphenols that include anti-oxidant,anti-tumor,anti-inflammation and metabolic regulation.Tea polyphenols such as theaflavins and catechins are considered to be multifunctional compounds that could be effective in the prevention or treatment of various cancers,cardiovascular disease,chronic inflammation,obesity,metabolic syndrome,and neurodegenerative diseases.In this review,we summarized the up-to-date research and underlying molecular mechanisms of black tea and its polyphenols.©2013 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

High-quality instant black tea manufactured using fresh tea leaves by two-stage submerged enzymatic processing

Repeated thermal treatment could impair the flavor of instant black tea(IBT)as the volatile compounds and characteristic constituents dramatically vary during the manufacturing process.Utilization of fresh leaves as raw material in IBT manufacture at low temperature may become an alternative to conventional extraction methods.This study aimed to improve the quality of IBT using fresh tea leaves by a two-stage enzymatic processing.The influence of combined enzymatic oxidation and extraction conditions for maximal extractable flavour(taste and aroma)characteristics from fresh tea leaves were investigated.The changes of aroma profiles and chemical constituents including theaflavins(TFs),thearubigins(TRs),theabrownines(TBs)and TRs/TFs ratio in converted tea brews under two-stage enzyme catalyzed fermentation and extraction conditions were further compared between different treatments,based on which the optimised conditions were determined.During the two-stage enzymatic processing,75 kinds of volatile compounds were identified in all processed samples,and the contents of TFs,TRs,TBs and TRs/TFs ratio could be optimized by adjusting different procedures and parameters.The overall properties of final product were compared with two types of commercial IBT.High quality IBT with desired properties and antioxidant activity can be manufactured using fresh tea leaves by two-stage enzymatic processing approach.

Isolation and identification of Starmerella davenportii strain Do18 and its application in black tea beverage fermentation

The objective of this study was to isolate and identify a yeast strain from the kombucha beverage and evaluate its potential as a novel starter in beverage fermentation in vitro.Starmerella davenportii Do18 was characterized for its cholesterol reduction;growth at different conditions such as temperatures(25,30,37 and 42◦C),low pH(1.2,1.5,2.03.0,and 7.0),bile salts(0%,0.25%,0.5%,1%and 2%)high-sucrose stress(2%,10%,20%,40%and 60%);and in-vitro survival in gastric and intestinal environments.Results showed that the yeast strain has a cholesterol-lowering capacity of 45%±2%,grew at temperature of 37◦C and is resistant to pH 1.5,2%bile and 40%sucrose solution,could survive in simulated gastric and intestinal environments.The physicochemical characteristics of the fermented beverages were also evaluated,which indicated that the yeast has pH reduction capacity and can produce organic acids and volatile compound such as 2-phenylethanol.Furthermore,the fermented beverage also has high total phenolics and flavonoids content and showed great antioxidant and antimicrobial activities.Therefore,the findings of this research provide strong evidence that S.davenportii Do18 has good fermentation properties,can be a potential starter in food and beverage fermentation.

The Joint Use of Electronic Nose and Electronic Tongue for the Evaluation of the Sensorial Properties of Green and Black Tea Infusions as Related to Their Chemical Composition

The objectives of the present study were to determine the effects of the brewing method on the amount of the major catechins, methylxanthines, total polyphenols and antioxidant capacity in green and black teas, and to correlate the chemical composition of tea infusions to their sensorial properties by the combined use of the electronic nose and tongue. For this purpose, tea infusions were prepared from 7 green teas and 6 black teas using different extraction times (3 - 5 and 10 min). The extraction of total polyphenols and catechins was increased by prolonging the infusion time from 3 - 5 to 10 min, while the caffeine amounts did not increase. The antioxidant activity of teas was well correlated with polyphenol content. Electronic tongue and electronic nose were able to discriminate green teas from black teas on the basis of their sensorial properties. Considering the taste, green teas were characterized by astringency and aftertaste-astringency and this sensation was increased by prolonging the infusion time;black teas were perceived as more bitter, sour, salty and the extraction time affected the astringent sensation. The aroma of green and black teas was discriminated by specific sensors and the increase of the extraction time produced more richly flavoured infusions. This work adds information about correlation between sensorial properties, antioxidant capacity and chemical composition of green and black teas.

Relation of tea ingestion to salivary redox and flow rate in healthy subjects

The biochemistry of human saliva can be altered by food intake.The benefits of tea drinking were extensively studied but the influence of tea ingestion on human saliva has not been revealed.The work aimed to investigate the immediate and delayed effect of vine tea,oolong tea and black tea intake on certain salivary biochemistry and flow rate.The saliva samples of healthy subjects were collected before,after and 30 min after tea ingestion.The chemical compositions and antioxidant capacity of tea samples were analyzed to correlate with salivary parameters.Principal component analysis indicated that the effects of vine tea consumption were dominated by increasing salivary flow rate(SFR),production rate of total protein(TPC),thiol(SH),malondialdehyde,catalase activity and antioxidant capacity(FRAP)in saliva.The antioxidant profile of studied tea samples(FRAP,polyphenols,flavonoids)was positively correlated with salivary SFR,TPC,SH and FRAP but negatively correlated with salivary uric acid concentration in saliva.

Black tea markets worldwide: Are they integrated?

Global tea consumption has risen significantly alongside rapid expansion of international trade in recent years.However,few studies have systematically examined the relationship among the major tea markets worldwide.Using weekly data from 2012-2019,this study empirically analyzed the price series of the world’s major black tea auction markets.The estimation results showed that these markets are connected,even though heterogeneities vary.This finding holds not only for regional markets but also for international markets.The findings offer important implications for tea-producing countries with millions of smallholder farmers.

Gas chromatographic method for the determination of hexaconazole residues in black tea

A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (GC-NPD) for the identification and quantitation of hexaconazole. The most appropriate solvent mixture for extracting hexaconazole residues from black tea was n-hexane:acetone at 1:1 (v/v). The extract was cleaned up by adsorption column chromatography using activated florisil. Performance of the method was assessed by evaluating quality parameters such as recovery value, repeatability, reproducibility, linearity and limits of detection and quantitation. When the method was assessed for repeatability, the percentage of recovery ranged between 86% and 96% while the relative standard deviation was between 0.30% and 2.35%. In studies on reproducibility the recovery ranged from 81% to 85% and relative standard deviation from 1.68% to 5.13%, implying that the method was reliable. A field trial was conducted to verify the application of this method with real samples. Results prove that the validated method was suitable for extracting hexaconazole residues.

In vitro anti-hyaluronidase activity of Sri Lankan low grown orthodox orange pekoe grade black tea(Camellia sinensis L.)

Objective:To access the anti-hyaluronidase activity of Sri Lankan low grown orthodox orange pekoe（OP） grade black tea with a view to develop an anti-aging skin formulation.Methods:Five concentrations（0.125,0.250,0.500,1.000 and 2.000 mg/mL） of black tea brew（BTB） were made using a freeze dried sample of Sri Lankan low grown orthodox OP grade black tea which was prepared according to international organization for standardization specification.Epigallocatechin gallate（EGCG） was used as the reference agent（concentrations tested:0.012,0.025,0.050,0.100 and 0.200 mg/mL）.Anti-hyaluronidase activity of BTB and EGCG in vitro were ascertained spectrometrically using hyaluronic acid（from rooster comb）and bovine testicular hyaluronidase.Results:The results revealed that BTB had moderate[IC50=（1.09±0.12） mg/mL]and dose dependent（r2=0.94） anti-hyaluronidase activity.EGCG also exhibited dose dependent（r2=0.93,P【0.05） anti-hyaluronidase activity which was superior[IC50=（0.09±0.00） mg/mL]to BTB.Conclusions:Sri Lankan low grown orthodox OP gradc black tca has promising antihyaluronidase activity in vitro and has the potential to be used as an anti-aging cosmaceutical.In addition,it may prove useful as a beverage in the management of allergy,some joint diseases and cnvenomation.

Chemopreventive Effects of Black Tea Polyphenols in Mouse Skin Model of Carcinogenesis

In the present investigations, the antitumorigenic effect of black tea polyphenols (BTP) in twcrstage mouse skin model of carcinogenesis was studied. The animals were initiated with a single 'subcarcinogenic' topical dose (52 μg/200 μl acetone ) of 7, 12-dimethylbenzanthracene (DMBA). To evaluate the anti-tumour initiating activity, BTP was topically applied twice a week for three weeks prior to DMBA application, followed by topical treatment with 12-o-tetradecanoyl phorbol-13-acetate (TPA) (5 μg/200 μl acetone, 2x/wk. ) as promoter. For evaluation of antitumor promoting activity, BTP was applied prior to each treatment of TPA. BTP application showed marked inhibitory effect as antitumour initiator as well as antitumour promoter in mouse skin medel of two-stage carcinogenesis. Since initiation involves genetic pathway and tumour promotion involves epigenetic pathway, it seems that BTP exerts its antitumorigenic effect by altering both genetic and epigenetic pathways

Determination of Vitamin B₁₂in Chinese Black Tea Leaves

We determined vitamin B12 content of Chinese black tea leaves using a microbiological assay based on Lactobacillus delbrueckii ATCC 7830. Trace levels (0.25 - 0.69 μg/100g dry weight) of vitamin B12 were detected in Pu’er, Fu, and Brick tea leaves. However, vitamin B12 content (0.06 - 1.37 μg/100g dry weight) of Ryubao tea leaves significantly varied. To determine whether Chinese black tea leaves contain vitamin B12 or other corrinoid compounds that are inactive in humans, corrinoid compounds were purified from Ryubao tea by an immunoaffinity column chromatography and vitamin B12 was identified by liquid chromatography-electrospray ionization/tandem mass spectrometry. Vitamin B12 content in the tea drink prepared from Ryubao tea leaves was very low (0.8 ng/100mL). Our results indicate that Chinese black tea is usually not a good source of B12, although Ryubao tea leaves with the highest B12 content may be utilized as a source of this vitamin for vegerarians.

Potential prebiotic effects of nonabsorptive components of Keemun and Dianhong black tea:an in vitro study

Black tea is a healthy and popular tea beverage.However,its main bioactive compounds(theaflavins and thearubigins)are not easily absorbed.The aim of this study was to investigate the modulation of intestinal microbiota by the nonabsorptive components of Keemun black tea(KBT)and Dianhong black tea(DBT),and fructooligosaccharide(FOS)was selected for use in the control group.KBT,DBT,and FOS significantly increased total short-chain acid production.Specifically,FOS treatment predominantly increased the production of acetic acids and black tea treatments increased the production of acetic,propionic,and butyric acids at similar rates.Moreover,FOS exerted a strong bifidogenic effect after 24 h of fermentation;KBT and DBT increased the abundance of the beneficial genus Bacteroides and Roseburia.In summary,the nonabsorptive components of KBT and DBT could serve as novel prebiotics,the underlying mechanisms of which are quite different from those of FOS.

Peroxidase Inhibition and Antioxidant Activity of Bulk-Marketed Black Tea (<i>Camellia sinensis</i>L.) from the Democratic Republic of the Congo

The widely known leaves of Camellia sinensis (L.) derive the most consumed beverage globally. All over the world, like in the Democratic Republic of the Congo (DR Congo), they are marketed in the form of packaged and in bulk black tea. The aim of this study was to report the microscopic botanical features, the chromatographic fingerprints, the antioxidant activities, and the peroxidase inhibition of bulk-marketed black teas consumed in DR Congo. The microscopic analysis of powders from unpackaged black tea marketed in DR Congo allowed the identification of specific microscopical features, which are characteristic to C. sinensis (L.) such as numerous asterosclerites, numerous fragments of unicellular trichomes;fragments of abaxial epidermis consisting of cells with slightly wavy walls, numerous anomocytic stomata, and the detection of biological contaminants, e.g. the dust mites. TLC and HPLC analysis indicated that flavonoids (hyperoside, rutin) and phenolic acids (chlorogenic acid, gallic acid) were major phenolic compounds, along with other secondary metabolites. Aqueous extracts from all bulk-marketed black teas exhibited good antioxidant activities at the concentrations range of 1 - 20 μg·mL-1 using in vitro ABTS and DPPH assays. These extracts showed equally inhibitory effects on myeloperoxidase (MPO) and horseradish peroxidase (HRP) activities at the concentration ranges of 1 - 20 μg·mL-1 and 20 - 100 μg·mL-1 respectively. Bulk-marketed black teas consumed in DR Congo possess antioxidant and anti-inflammatory properties comparable to packaged Ceylon tea largely marketed. The observed bioactivities support the health benefits of the consumed black tea by Congolese people, despite the storage conditions to be improved in order to preserve its nutritional and therapeutic assets.

Discrimination of Green,Oolong,and Black Teas by GC-MS Analysis of Characteristic Volatile Flavor Compounds

Tea is one of the most consumed beverages in the world and its quality is influenced by geographical origin and production methods. This study focuses on the volatile aroma components of 38 tea products from China, Japan, Indonesia, Sri-Lanka, and Chinese Taipei;among them 7 green teas, 13 oolong teas, and 18 black teas. The volatiles were extracted from the infusions using PorapakQ-resin, concentrated, and analyzed by gas chromatography-mass spectrometry. The components were identified by authentic reference compounds or preliminary based on their mass spectra. Different manufacturing processes yield different blends of aroma compounds. In general, the contents of total volatiles, aliphatics, aromatics, and terpenoids increased with the fermentation degree, whereas jasmine lactone and indole were the highest in oolong teas. Some particular manufacturing processes, for example, the use of tea leaves infested by the tea green leafhopper, lead to higher contents of volatiles in final products as in Oriental Beauty oolong tea. The relative peak areas determined for 82 volatiles were the basis for the statistical analysis and highlight the potential of multivariate analysis to distinguish tea samples of different categories.

Degradation of black tea theaflavin through C-ring cleavage by gut microbiota

Increasing evidence has shown that gut microbiota plays important roles in metabolizing large molecular polyphenols to bioavailable and bioactive microbial metabolites.Theaflavin(TF)is one of the major color compounds in black tea and has demonstrated anti-inflammation,antioxidant,and anticancer effects properties.However,little is known about the metabolism of TF by gut microbiota in vivo.In this study,following the administration of TF to mice,the C-ring cleavage metabolites,dihydro-and tetrahydro-theaflavin(DH-TF and TH-TF)were detected in mouse feces by LC-MS and validated by authentic standards from in situ chemical reaction.The observation of the C-ring cleavage metabolites in TF-treated conventionalized mice but not in germ-free(GF)mice confirmed the role of gut microbiota in cleaving the C-rings of TF.The detection of DH-TF from the anaerobic incubation of TF with catechin-converting gut bacteria,Eggerthella lenta(Eggerth),suggested that the microbes with the capacity to cleave the C-ring of catechins were able to metabolize TF following the same mechanism.Additionally,three small phenolic metabolites were detected in mouse feces,and one of them was primarily detected in SPF mice not GF mice,which revealed that TF,subsequent to the cleaved C-ring,can be further metabolized into smaller phenolic metabolites by gut microbiota.Dose-dependent production of these metabolites were observed from the administration of 100 mg/kg to 400 mg/kg body weight of TF.In conclusion,gut microbiota can metabolize TF to the open-ring metabolites and the phenolic metabolites through the C-ring cleavage in mice.

Aluminum Contents in Dry Leaves and Infusions of Commercial Black and Green Tea Leaves: Effects of Sucrose and Ascorbic Acid Added to Infusions

Tea consumption has increased due to its beneficial effects. Results from a lab study on the effect of sucrose (5 g per cup, 150 mL) and/or ascorbic acid (2 mL per cup, 150 mL) on dissolved aluminum compounds during the infusion of two commercial types of dry tea leaves (black, green) with boiling water (5, 15 min infusion time) are presented. Factors influencing the presence of dissolved aluminum in the infusions of both tea leaves were infusion time and sugar contents, as well as the interaction between ascorbic acid and sucrose (p < 0.05). Aluminum contents found after 15 min of infusion were 0.7 mg L–1 for black tea infusions added with sugar, and 0.69 mg L–1 for green tea added with both sugar and ascorbic acid. Both concentrations are higher than the level accepted in Mexico for drinking water (there is no act concerning tea infusions), that is 0.2 mg L–1.

Optimization of Response Surface of Ultrasonic-assisted Extraction of Rizhao Black Tea

[ Objectivel The aim was to determine the optimal technology for ultrasonic-assisted extraction of black tea was determined. [ Methed] Taking Black Tea as materials, the Box-Behnken response surface design method of tea polyphenols ultrasonic-assisted extraction process optimi- zation was applied. The regression optimization model of the ethanol volume fraction, ultrasonic time, and ultrasonic temperature, ethyl acetate extract stalling time and tea polyphenols was established. [ Result] The influence of four factors on the black tea polyphenol solvents affecting size was as follows： ultrasonic time 〉 ethanol volume fraction 〉 stalling extraction time 〉 ultrasound temperature. The best extraction process was ultrasonic time 80 min, volume fraction of 88.99% ethanol, extraction time 89.97 min, ultrasonic temperature of 80℃. At the optimized technical parameters, the black tea phenolic extraction yield can be as high as 73.50%. [ Conclusion] The study provided theoretical basis for the development of tea leaves and black tea.

中国最早出口的茶类是黑茶——分析“black tea”与红茶的关系推断

红茶为何在英语里叫"black tea",一直在这方面找不到可靠可信的依据,同样也缺少相关的研究。本文试图从黑茶与红茶的起源到后来茶叶的分类,再到茶叶的出口等方面进行探索,初步得出一个结论,即中国最早出口的茶类是黑茶。这仅仅是抛出一个命题,同样缺乏强有力的理论和历史证据,希望能有更多的茶叶爱好者开展这方面的研究讨论。