Theaflavin Research Articles

Inhibitory effect of black tea (Camellia sinensis) theaflavins and thearubigins against HCT 116 colon cancer cells and HT 460 lung cancer cells.

Recently, phytochemical-based dietary intervention has gained attention as a preventive and curative strategy against cancers owing to their safety, better tolerance, and economics. Against this background, black tea extract which contains the flavanol-3-ol, theaflavins (TF), and thearubigins (TR) with promising anti-oncogenic activity were assessed to determine its in vitro inhibitory impact on colon cancer (HCT 116) and lung cancer cell lines (HT 460). In a dose-dependent manner, results revealed that TF, TR, and their combinations cause inhibition in cell viability. However, TF imparted a maximum reduction in cell viability of HCT 116 and HT 460. Flow cytometry data revealed that TF, TR, and their combinations exhibited substantial cell arrest at the G2/M phase. The influence was more prominent in lung cancer cells (HT 460) when compared with colon cells (HCT 116). All treatments resulted in apoptosis, however, the combination of TF and TR exhibited the highest apoptotic ability in comparison to individual treatments. TF and TR exhibited a synergistic impact and significantly inhibited cell proliferation of HCT 116 and HT 460 in dose- and time-dependent manners by inducing apoptosis and cell cycle arrest, wherein TF showed a more pronounced impact. PRACTICAL APPLICATIONS: Results from the present study revealed that black tea-isolated polyphenols (TF and TR) exhibited a significant inhibition of lung and colon cancer cell growth. A promising synergistic effect of TF and TR as inhibitors of cancer cells was observed. More clinical work, perhaps on a human subject, is needed before these two isolated compounds can be prescribed as anticancer drugs.

Green Tea Polyphenols Modify the Gut Microbiome in db/db Mice as Co-Abundance Groups Correlating with the Blood Glucose Lowering Effect.

The effects of green tea polyphenols, Polyphenon E (PPE), and black tea polyphenols, theaflavins (TFs), on gut microbiota and development of diabetes in db/db mice are investigated and compared. Supplementation of PPE (0.1%) in the diet of female db/db mice for 7 weeks decreases fasting blood glucose levels and mesenteric fat while increasing the serum level of insulin, possibly through protection against β-cell damage. However, TFs are less or not effective. Microbiome analysis through 16S rRNA gene sequencing shows that PPE and TFs treatments significantly alter the bacterial community structure in the cecum and colon, but not in the ileum. The key bacterial phylotypes responding to the treatments are then clustered into 11 co-abundance groups (CAGs). CAGs 6 and 7, significantly increased by PPE but not by TFs, are negatively associated with blood glucose levels. The operational taxonomic units in these CAGs are from two different phyla, Firmicutes and Bacteroidetes. CAG 10, decreased by PPE and TFs, is positively associated with blood glucose levels. Gut microbiota respond to tea polyphenol treatments as CAGs instead of taxa. Some of the CAGs associated with the blood glucose lowering effect are enriched by PPE, but not TFs.

Systematic characterisation of the structure and radical scavenging potency of Pu'Er tea () polyphenol theaflavin.

The structure, energetics and radical scavenging potency of theaflavin (TF), a natural polyphenolic antioxidant found in oxidised tea, have been characterised by a series of density functional theory (DFT) determinations. Exploratory conformational searches yielded 153 distinct neutral structures. Results showed TF's structural preferences to be regulated by its unique fused double ring benzotropolone moiety, and its degree of planarity, with structural diversity, principally arising from variations of its nine -OH groups. The distinct 3D conformational 'poses' are shown to be stabilised by a complex network of intra-system interactions, damping overall structural floppiness. This rigidification, together with stability, is shown to be coupled with radical scavenging potency in the TF system. Radical scavenging via hydrogen atom abstraction (HAB) in H2O solution was determined to be spontaneous with very low reaction barriers (ΔGrel ∼ 4 kJ mol-1).

PENINGKATAN SEL OSTEOBLAST MANDIBULA TIKUS WISTAR JANTAN SETELAH PEMBERIAN FERMENTASI TEH KOMBUCHA

Osteoblasts are bone-forming cells to grow and play a role in regulation of bone metabolism, including alveolar bone. Imbalance of osteoblasts number in bone formation may lead loss of bone mass, which is causes osteoporosis. Reactive Oxygen Species (ROS) is an oxidant that take important roles in osteoclast activation, osteoclastogenesis and activation of osteoblasts inhibition. Kombucha tea has antioxidant effects. This study was conducted to determine Kombucha tea fermented on 14 days make the osteoblasts in the mandibular bone of male wistar rat more numerous.This research was a purely experimental method with Randomized Post Test Control Group Design. Subjects consisted of ten of three – month male wistar rats were divided into 2 groups. Control group received aquadest for 30 days, on the other hand the treatment group were treated by 8 ml of Kombucha tea for 30 days. On the 31st day, rats were euthanized for tissue sampling and histological preparation of mandibular bone and subjected for HE staining. The test results based on comparison between the control group and treatment group with independent t-test showed that there were significant differences in osteoblasts number in mandibular bone of wistar rats (p<0.05). Kombucha tea contain epicatechin gallate (ECG) that stimulate osteoblasts differentiation and inhibit induction of Receptor Activator Of Nuclear Factor-κB Ligand (RANKL). Further more, Epigallocatechin gallate (EGCG) and theaflavin (TF) detoxify molecules of ROS and enhance osteoblastogenesis. This study concluded that administration of Kombucha tea fermented on 14 days make osteoblasts in the mandibular bone of wistar rat more numerous.

Theaflavins prevent cartilage degeneration via AKT/FOXO3 signaling invitro.

Theaflavins (TFs) are the main bioactive polyphenols in tea and contribute to protection against oxidative stress. Excessive reactive oxygen species (ROS) accumulation can lead to the disruption of cartilage homeostasis. The present study examined the potential effects of TFs on H2O2-induced cartilage degeneration in vitro. Cell Counting kit (CCK-8) was used to determine cell viability, and flow cytometric analysis was used to detect ROS, apoptosis and DNA damage. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to detect the expression levels of target factors. The present study revealed that TFs effectively reduced the expression of catabolic factors, including matrix metalloproteinase-13, interleukin-1 and cartilage glycoprotein 39. TFs inhibited ROS generation in cartilage degeneration, and suppressed apoptosis and DNA damage caused by oxidative stress. TFs also downregulated the expression levels of cleaved caspase-3 and B-cell lymphoma 2-associated X protein, and the DNA damage-related genes, ATR serine/threonine kinase and ATM serine/threonine kinase. Furthermore, TFs enhanced the activity of glutathione peroxidase 1 and catalase, but reduced the expression levels of phosphorylated (p)-AKT serine/threonine kinase (AKT) and p-Forkhead box O3 (FOXO3)a. Conversely, the effects of TFs on apoptosis and DNA damage were reversed by persistent activation of AKT. In conclusion, TFs prevented cartilage degeneration via AKT/FOXO3 signaling in vitro. The present study suggested that TFs may be a potential candidate drug for the prevention of cartilage degeneration.

Theaflavin and epigallocatechin-3-gallate synergistically induce apoptosis through inhibition of PI3K/Akt signaling upon depolymerizing microtubules in HeLa cells.

Theaflavin (TF) and epigallocatechin-3-gallate (EGCG) both have been reported previously as microtubule depolymerizing agents that also have anticancer effects on various cancer cell lines and in animal models. Here, we have applied TF and EGCG in combination on HeLa cells to investigate if they can potentiate each other to improve their anticancer effect in lower doses and the underlying mechanism. We found that TF and EGCG acted synergistically, in lower doses, to inhibit the growth of HeLa cells. We found the combination of 50 µg/mL TF and 20 µg/mL EGCG to be the most effective combination with a combination index of 0.28. The same combination caused larger accumulation of cells in the G 2 /M phase of the cell cycle, potent mitochondrial membrane potential loss, and synergistic augmentation of apoptosis. We have shown that synergistic activity might be due to stronger microtubule depolymerization by simultaneous binding of TF and EGCG at different sites on tubulin: TF binds at vinblastine binding site on tubulin, and EGCG binds near colchicines binding site on tubulin. A detailed mechanistic analysis revealed that stronger microtubule depolymerization caused effective downregulation of PI3K/Akt signaling and potently induced mitochondrial apoptotic signals, which ultimately resulted in the apoptotic death of HeLa cells in a synergistic manner.

Effects of theaflavins on tissue inflammation and bone resorption on experimental periodontitis in rats.

Background and ObjectiveTheaflavins (TFs), the major polyphenol in black tea, have the ability to reduce inflammation and bone resorption. The aim of this study was to evaluate the effects of TFs on experimental periodontitis in rats.Material and MethodsThirty rats were divided into five groups: Control (glycerol application without ligation), Ligature (glycerol application with ligation), TF1 (1 mg/mL TF application with ligation), TF10 (10 mg/mL TF application with ligation), and TF100 (100 mg/mL TF application with ligation). To induce experimental periodontitis, ligatures were placed around maxillary first molars bilaterally. After ligature placement, 100 μL glycerol or TFs were topically applied to the rats daily, and rats were euthanized 7 days after ligature placement. Micro‐computed tomography was used to measure bone resorption in the left side of the maxilla, and quantitative polymerase chain reaction was used to measure the expression of interleukin (IL)‐6, growth‐regulated gene product/cytokine‐induced neutrophil chemoattractant (Gro/Cinc‐1, rat equivalent of IL‐8), matrix metalloproteinase‐9 (Mmp‐9), receptor activator of nuclear factor‐kappa Β ligand (Rankl), osteoprotegerin (Opg), and the Rankl/Opg ratio in gingival tissue. With tissue from the right side of the maxilla, hematoxylin and eosin staining was used for histological analysis, immunohistochemical staining for leukocyte common antigen (CD45) was used to assess inflammation, and tartrate‐resistant acid phosphatase (TRAP) staining was used to observe the number of osteoclasts.ResultsThe TF10 and TF100 groups, but not the TF1 group, had significant inhibition of alveolar bone loss, reduction in inflammatory cell infiltration in the periodontium, and significantly reduced numbers of CD45‐positive cells and TRAP‐positive osteoclasts compared with the Ligature group. Correspondingly, the TF10 and TF100 groups had significantly downregulated gene expression of IL‐6, Gro/Cinc‐1(IL‐8), Mmp‐9, and Rankl, but not of Opg. Consequently, Rankl/Opg expression was significantly increased in the Ligation group but was attenuated in the TF10 and TF100 groups.ConclusionThe results of this study suggest that topical application of TFs may reduce inflammation and bone resorption in experimental periodontitis. Therefore, TFs have therapeutic potential in the treatment of periodontal disease.

Theaflavins attenuate ethanol‑induced oxidative stress and cell apoptosis in gastric mucosa epithelial cells via downregulation of the mitogen‑activated protein kinase pathway.

Ethanol-induced diseases of the gastric mucosa are the most common and refractory diseases of gastrointestinal system in clinic, and are mediated by oxidative stress and apoptosis pathways. Theaflavins (TFs) are considered to be antioxidants. The present study aimed to determine the molecular mechanism underlying the ability of TFs to attenuate ethanol-induced oxidative stress and apoptosis in GES-1 gastric mucosa epithelial cells. A Cell Counting Kit-8 (CCK-8) assay was performed to investigate the cell viability of GES-1 cells following administration of ethanol (0.5 mol/l) and subsequent treatment with TFs (20, 40 and 80 µg/ml) for specific time intervals. A carboxyfluorescein diacetate succinimidyl ester assay was used to measure proliferation and further investigate the results of the CCK-8 assay. Flow cytometry was performed to measure reactive oxygen species (ROS) levels and the apoptosis rates of GES-1 cells. Furthermore, levels of oxidative stress-associated factors, including malondialdehyde, superoxide dismutase and glutathione, were investigated using commercial kits. Reverse transcription-quantitative polymerase chain reaction and western blot assays were performed to determine the expression levels of apoptosis-associated factors, as well as the phosphorylation levels of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 kinase (p38). The results of the present study demonstrated that treatment with ethanol inhibited GES-1 cell proliferation, and enhanced ROS levels and apoptosis rates, potentially via downregulation of B-cell lymphoma-2 (Bcl-2) expression and upregulation of Bcl-2-associated X and caspase-3 expression levels, as well as enhancing the phosphorylation levels of ERK, JNK and p38. However, treatment with TFs was revealed to attenuate the effects of ethanol administration on GES-1 cells in a dose-dependent manner. In conclusion, TFs may attenuate ethanol-induced oxidative stress and apoptosis in gastric mucosa epithelial cells via downregulation of various mitogen-activated protein kinase pathways.

Antioxidant activity and effects of Kenyan Tea (Camellia sinensis) on the liver function and serum biochemistry in male Wistar rats

Background: Tea is a beverage that is most widely consumed worldwide. Studies have shown that oral consumption of tea has health benefits however, there is paucity of data in Kenya detailing the biochemical effects of tea in the liver and elucidation of its mechanism of action.Methods: The polyphenol composition and antioxidant capacity of tea were determined by HPLC and the Folins Ciocalteu spectrophotometric methods. Metal levels were determined using flame Atomic Absorption Spectrometer (AAS). Aqueous black and green tea extracts were administered to the rats at dosages of 400mg/kg b.w.t. The effect of tea on total blood proteins, Albumin, ZHX1, TBARS, AST, ALP and ALT were determined by spectrophotometric methods. The body weight of each rat was also determined at one week interval.Results: Total Polyphenols (TP), Total Catechins (TC) and Antioxidant Activity (AA) between the black and green teas were significantly (P<0.05) different. Green tea had the highest levels of TP (19.70-26.12%), TC (8.51%-17.60%) and AA (86.65%-94.50%). Tea did not have a significant (P>0.05) effect on TP, ALB, ALT, AST, ALP, MDA and ZHX1 in the test animals compared with the controls. This data indicates that green tea is rich in catechins while black tea being rich in Theaflavins (TFs) and Thearubigins (TRs). Both tea products possess essential and non-essential metals well within the maximum permissible concentrations.Conclusions: Findings from this study indicate both green and black tea aqueous extracts have polyphenols and high antioxidant activity. Administration of the aqueous tea extracts have no toxicological effect on the liver.

Optimization of feeding rate and pressure of Orthodox Roller in Black Tea production

The objective of this study was to optimize the performance of orthodox roller (225 kg) in black tea manufacturing by varying the pressure and feeding rate at Wewassa Tea Factory, Passara. Three levels of pressure (P1 - 10 min-no pressure, 10 min-touch bar, P2 - 10 min-no pressure, 5 min-1/4 pressure,5min-no pressure and P3 - 10 min - no pressure, 3 min-1/4 pressure, 2 min - 1/2 pressure) and three levels of feeding rate to the roller (200, 205 and 210 kg) were used as treatment combinations. Currently, the factory using P1 pressure and 200 kg feeding rate for tea manufacturing. Particle size analysis, brightness, TF/TR and organoleptic properties were measured for the triplicate samples and compared with the sample prepared with the factory standard. The results revealed, there is a significant effect of pressure and feeding rate on particle size analysis, but there is no significant effect on color, ratio between theaflavins (TF), thearubigins (TR) and sensory analysis (p<0.05) The treatment combination of feeding rate 210 kg and Pressure P2 has given high amount of particle size belongs to No 3 mesh size while conserving other chemical and organoleptic parameters, thus it can be concluded that this treatment combination is the best.

Theaflavin alleviates inflammatory response and brain injury induced by cerebral hemorrhage via inhibiting the nuclear transcription factor kappa β-related pathway in rats.

ObjectiveIntracerebral hemorrhage (ICH) is one of the most common acute cerebrovascular diseases with high mortality. Numerous studies have shown that inflammatory response played an important role in ICH-induced brain injury. Theaflavin (TF) extracted from black tea has various biological functions including anti-inflammatory activity. In this study, we investigated whether TF could inhibit ICH-induced inflammatory response in rats and explored its mechanism.Materials and methodsICH rat models were induced with type VII collagenase and pretreated with TF by gavage in different doses (25 mg/kg–100 mg/kg). Twenty-four hours after ICH attack, we evaluated the rats’ behavioral performance, the blood–brain barrier (BBB) integrity, and the formation of cerebral edema. The levels of reactive oxygen species (ROS) and inflammatory cytokines were examined by 2′,7′-dichlorofluorescin diacetate and enzyme-linked immunosorbent assay. Nissl staining and transferase dUTP nick end labeling (TUNEL) were aimed to detect the neuron loss and apoptosis, the mechanism of which was explored by Western blot.ResultsIt was found that in the pretreated ICH rats TF significantly alleviated the behavioral defects, protected BBB integrity, and decreased the formation of cerebral edema and the levels of ROS as well as inflammatory cytokines (including interleukin-1 beta [IL-1β], IL-18, tumor nectosis factor-alpha, interferon-γ, transforming growth factor beta, and (C-X-C motif) ligand 1 [CXCL1]). Nissl staining and TUNEL displayed TF could protect against the neuron loss and apoptosis via inhibiting the activation of nuclear transcription factor kappa-β-p65 (NF-κβ-p65), caspase-1, and IL-1β. We also found that phorbol 12-myristate 13-acetate, a nonspecific activator of NF-κβ-p65, weakened the positive effect of TF on ICH-induced neural defects and neuron apoptosis by upregulating NF-κβ-related signaling pathway.ConclusionTF could alleviate ICH-induced inflammatory responses and brain injury in rats via inhibiting NF-κβ-related pathway, which may provide a new way for the therapy of ICH.

Differentiation of black tea infusions according to origin, processing and botanical varieties using multivariate statistical analysis of LC-MS data

A data set of sixty samples of diverse black tea were collected and analysed using high-performance liquid chromatography-mass spectrometry (HPLC-MS) methods. Chemical variations of black tea infusions depending on origin, botanical variety, and processing were investigated employing various multivariate statistical techniques including principal component analysis (PCA), hierarchical cluster analysis (HCA), partial least squares discriminant analysis (PLS-DA) and analysis of variance (ANOVA).In particular, PLS-DA allowed identification of a variety of marker compounds responsible for differences among black teas of different origin, plant variety and processing methods used.Among most variable compounds are catechins, derivatives of quercetin, apigenin, quinic acid, and kaempferol. Rutin, epigallocatechin gallate (EGCG), quinic acid and theaflavin (TF) were contributing to most variances. Products of black tea fermentation (theaflavin, theasinensin, and theacitrin derivatives) contributed to PLS-DA associated to the processing of black tea.

Theaflavin-3-gallate specifically interacts with phosphatidylcholine, forming a precipitate resistant against the detergent action of bile salt.

Black tea is a highly popular beverage, and its pigments, polymerized catechins such as theaflavins (TFs), are attracting attention due to their beneficial health effects. In this study, to test the inhibitory activities of TFs on the intestinal absorption of cholesterol, we investigated their effects on phosphatidylcholine (PC) vesicles in the absence or presence of a bile salt. (-)-Epicatechin gallate, (-)-epigallocatechin gallate, and TFs formed insoluble complexes with PC vesicles. Galloylated TFs such as TF2A, TF2B, and TF3 precipitated far more than other polyphenols. The subsequent addition of taurocholate redispersed the polyphenol-PC complexes, except that a large amount of TF2A remained insoluble. After incubation with taurocholate-PC micelles, TF2A elevated the turbidity of the micelle solution, providing red sediments. The TF2A-specific effect was dependent on the PC concentration. These results suggest that TF2A interacts with PC and aggregates in a specific manner different from catechins and other TFs.

EFFECTS OF THEAFLAVINS ON GASTRIC CANCER CELL LINE

Objective: The objective of this study was to evaluate the anticarcinogenic effects of theaflavins (TFs), component of black tea, on human gastric cancer cell line.Materials and Methods: Cell viability was assessed by WST-1 reagent. Acridine orange (AO) and ethidium bromide (EB) fluorescence staining method were used to detect apoptotic cells, if any, followed by flow cytometric detection. To evaluate the molecular basis for understanding the apoptotic pathway, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were measured. Pro- and anti-apoptotic protein and gene expressions were detected by western blot and real-time techniques.Results: TFs-treated AGS cell indicated apoptosis-mediated cell death. The presence of TFs induced the generation of ROS and which in turn changes the MMP with the elevated level of cyt c, activation of caspase-9, caspase-3, and PARP cleavage. Our study also showed that TFs treatment altered the Bax/Bcl2 ratio and upregulated the expression of p53.Conclusion: All these observations lead to the fact that TFs developed potential chemopreventive effects through the induction of apoptosis through mitochondria-mediated death cascade in the human gastric cancer cell.

EFFECTS OF THEAFLAVINS ON GASTRIC CANCER CELL LINE

Objective: The objective of this study was to evaluate the anticarcinogenic effects of theaflavins (TFs), component of black tea, on human gastric cancer cell line.Materials and Methods: Cell viability was assessed by WST-1 reagent. Acridine orange (AO) and ethidium bromide (EB) fluorescence staining method were used to detect apoptotic cells, if any, followed by flow cytometric detection. To evaluate the molecular basis for understanding the apoptotic pathway, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were measured. Pro- and anti-apoptotic protein and gene expressions were detected by western blot and real-time techniques.Results: TFs-treated AGS cell indicated apoptosis-mediated cell death. The presence of TFs induced the generation of ROS and which in turn changes the MMP with the elevated level of cyt c, activation of caspase-9, caspase-3, and PARP cleavage. Our study also showed that TFs treatment altered the Bax/Bcl2 ratio and upregulated the expression of p53.Conclusion: All these observations lead to the fact that TFs developed potential chemopreventive effects through the induction of apoptosis through mitochondria-mediated death cascade in the human gastric cancer cell.

Theaflavin ameliorates ionizing radiation-induced hematopoietic injury via the NRF2 pathway

It has been well established that reactive oxygen species (ROS) play a critical role in ionizing radiation (IR)-induced hematopoietic injury. Theaflavin (TF), a polyphenolic compound from black tea, has been implicated in the regulation of endogenous cellular antioxidant systems. However, it remains unclear whether TF could ameliorate IR-induced hematopoietic injury, particularly the hematopoietic stem cell (HSC) injury. In this study, we explored the potential role of TF in IR-induced HSC injury and the underlying mechanism in a total body irradiation (TBI) mouse model. Our results showed that TF improved survival of irradiated wild-type mice and ameliorated TBI-induced hematopoietic injury by attenuating myelosuppression and myeloid skewing, increasing HSC frequency, and promoting reconstitution of irradiated HSCs. Furthermore, TF inhibited TBI-induced HSC senescence. These effects of TF were associated with a decline in ROS levels and DNA damage in irradiated HSCs. TF reduced oxidative stress mainly by up-regulating nuclear factor erythroid 2-related factor 2 (NRF2) and its downstream targets in irradiated Lineage-c-kit+ positive cells. However, TF failed to improve the survival, to increase HSC frequency and to reduce ROS levels of HSCs in irradiated Nrf2-/- mice. These findings suggest that TF ameliorates IR-induced HSC injury via the NRF2 pathway. Therefore, TF has the potential to be used as a radioprotective agent to ameliorate IR-induced hematopoietic injury.

Improving the quality of fermented black tea juice with oolong tea infusion

Fresh tea leaves were crushed into juice and then fermented (oxidation) to obtain fermented black tea juice, which can be used to prepare black tea beverage. The effects of addition of oolong tea infusion or tossing of tea leaves on the sensory quality and theaflavins (TFs) concentration of fermented black tea juice were investigated. The results showed that both addition of tea infusion and tossing of fresh tea leaves increased the TFs/thearubigins (TRs) ratio and improved the sensory quality of fermented black tea juice. The TFs/TRs ratio was found to be significantly correlated with the scores for flavor (r=0.98), mouth feel (r=0.94), and overall acceptability (r=0.91) of the fermented black tea juices from different processes. This result suggested that a relatively high concentration of catechins and stepwise enzymatic oxidation were the crucial factors that increased the TFs/TRs ratio and improved the sensory quality. The combination of adding tea infusion and tossing fresh tea leaves greatly improved the quality of the fermented black tea juice by markedly increasing the TFs/TRs ratio (87%). Results of the present study provided useful information for improving the quality of fermented black tea juice.

Molecular aspects of cancer chemopreventive and therapeutic efficacies of tea and tea polyphenols.

The natural dietary product tea (Camellia sinensis) and its bioactive polyphenols such as epigallocatechin gallate (EGCG) and theaflavin (TF) demonstrated potential anticancer effects in different preclinical and clinical studies. The aim of the present review was to understand the molecular mechanisms of the tea and tea polyphenol-mediated cancer prevention and therapy. In the setting of invivo cancer prevention studies, administration of the tea and tea polyphenols at preinitiation stages only showed partial prevention, whereas continuous administration showed potential effect in restriction of carcinogenesis in the body's multiple organs at early premalignant stages throughout the experiment. Similar to different invitro cancer cell models, treatment after initiation stages showed potential therapeutic efficacy invivo. But, the mechanisms of prevention and therapy were found to be similar regardless of tea and its polyphenols. They mainly serve as antioxidants and induce the detoxification system, thereby inhibiting carcinogen metabolism and cancer initiation. Additionally, they could inhibit self-renewal, proliferation, and survival of the tumor-initiating population in restriction of the carcinogenesis progression from cancer initiation and promotion. This might be a result of the modulation of membrane organization, interaction with DNA/RNA/proteins and epigenetic modifications, as well as regulation of cellular replicative potential by the tea polyphenols.

Synthesis and isolation of theaflavin from fresh tea leaves as bioactive ingredient of antioxidant supplements

Theaflavin (TF) is a product of catechin oxidation that give contribution to golden yellow color, brightness, briskness of black tea and has a potential as natural antioxidant activity. TF has a higher superoxide radical capture rate than EGCG (Epigallocatechin gallate). The study was to synthesize TF components in the form of extracts that have high antioxidants. Materials used in this research is bud+3 leaves from RITC clone (GMB 7). The research were caried out used 15 liters of tea leaves pulp per treatment, fermentation using fermentor with 15 L/min, 20 L/min and 25 L/min airflow treatment, separation of TF from thearubigin (TR) used 2.5% NaHCO3, and isolation of TF from impurity compounds used silica gel column with ethyl acetate/hexane as eluent, and DPPH (1,1-diphenyl-2-picryl hydrazyl) for antioxidant activity. The result showed that TF synthesis of fresh tea leaf catechin at water-air rate of 25 liters/minute could produced TF extract and yield TF purity extract with 1.01% and 39.15% in dry weight respectively after isolation by silica gel column. Antioxidant activity by DPPH from TF extract showed the smallest value of EC50 is 12.16 mg/L at 150 mg dose and its activity increased with the addition of concentration of TF extract.

Feature Fusion for Prediction of Theaflavin and Thearubigin in Tea Using Electronic Tongue

Liquor characteristics of black cut, tear, and curl tea mostly depend on two biochemical components like theaflavin (TF) and thearubigin (TR). Evaluation of tea quality can be done efficiently by estimating the concentration of TF and TR without using biochemical tests as it takes much time, which requires laborious effort for sample preparation, storage, and measurement. Moreover, the required instruments for this test are very costly. In this paper, we have proposed an efficient method of TF and TR prediction in a given tea sample using electronic tongue (ET) signal. Combinations of transformed features, like discrete cosine transform, Stockwell transform (ST), and singular value decomposition, of ET signals are fused to develop regression models to predict the contents of TF, TR, and TR/TF. Three different regression models such as artificial neural network, vector-valued regularized kernel function approximation, and support vector regression are used to evaluate the performance of the proposed method. High prediction accuracy using fusion of features ensures the effectiveness of the proposed method for prediction of TF and TR using ET signals.