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Shengmin Sang - One of the best experts on this subject based on the ideXlab platform.
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The Microbiota Is Essential for the Generation of Black Tea Theaflavins-Derived Metabolites
2016Co-Authors: Huadong Chen, Javier Rivera Guzman, Nicholas D. Gillitt, Salam A. Ibrahim, Saeed Hayek, Shengmin SangAbstract:Background: Theaflavins including Theaflavin (TF), Theaflavin-3-gallate (TF3G), Theaflavin-39-gallate (TF39G), and Theaflavin-3,39-digallate (TFDG), are the most important bioactive polyphenols in black tea. Because of their poor systemic bioavailability, it is still unclear how these compounds can exert their biological functions. The objective of this study is to identify the microbial metabolites of Theaflavins in mice and in humans. Methods and Findings: In the present study, we gavaged specific pathogen free (SPF) mice and germ free (GF) mice with 200 mg/kg TFDG and identified TF, TF3G, TF39G, and gallic acid as the major fecal metabolites of TFDG in SPF mice. These metabolites were absent in TFDG- gavaged GF mice. The microbial bioconversion of TFDG, TF3G, and TF39G was also investigated in vitro using fecal slurries collected from three healthy human subjects. Our results indicate that TFDG is metabolized to TF, TF3G, TF39G, gallic acid, and pyrogallol by human microbiota. Moreover, both TF3G and TF39G are metabolized to TF, gallic acid, and pyrogallol by human microbiota. Importantly, we observed interindividual differences on the metabolism rate of gallic acid to pyrogallol among the three human subjects. In addition, we demonstrated that Lactobacillus plantarum 299v and Bacillus subtilis have the capacity to metabolize TFDG. Conclusions: The microbiota is important for the metabolism of Theaflavins in both mice and humans. The in vivo functiona
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The microbiota is essential for the generation of black tea Theaflavins-derived metabolites.
PloS one, 2012Co-Authors: Huadong Chen, Saeed A. Hayek, Javier Rivera Guzman, Nicholas D. Gillitt, Salam A. Ibrahim, Christian Jobin, Shengmin SangAbstract:Background Theaflavins including Theaflavin (TF), Theaflavin-3-gallate (TF3G), Theaflavin-3′-gallate (TF3′G), and Theaflavin-3,3′-digallate (TFDG), are the most important bioactive polyphenols in black tea. Because of their poor systemic bioavailability, it is still unclear how these compounds can exert their biological functions. The objective of this study is to identify the microbial metabolites of Theaflavins in mice and in humans.
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structural identification of Theaflavin trigallate and tetragallate from black tea using liquid chromatography electrospray ionization tandem mass spectrometry
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Huadong Chen, Kelly L Shurlknight, Tinchung Leung, Shengmin SangAbstract:Black tea contains two major pigments, Theaflavins and thearubigins. These polyphenols have been associated with certain health benefits including prevention of heart disease and cancer. Elucidating and characterizing the structural aspects of thearubigins, the most abundant pigment in black tea, has been a challenge for many years. Therefore further studies of black tea polyphenols must be conducted in effort to solve this thearubigin dispute. In the present study, black tea extract was found to possess Theaflavin trigallate and tetragallate by means of liquid chromatography/electrospray ionization mass spectrometry. These structures were confirmed by analysis of the MS(n) (n = 1-4) spectra and comparison of the MS/MS spectra of the product ions to the MS/MS spectra of authentic (-)-epigallocatechin-3-gallate, (-)-epicatechin-3-gallate and Theaflavin-3,3'-digallate. To our knowledge, this is the first report to confirm the presence of Theaflavin trigallate and tetragallate in black tea.
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structural identification of mouse fecal metabolites of Theaflavin 3 3 digallate using liquid chromatography tandem mass spectrometry
Journal of Chromatography A, 2011Co-Authors: Huadong Chen, Nicholas D. Gillitt, Christian Jobin, Tiffany A Parks, Xiaoxin Chen, Shengmin SangAbstract:Black tea consumption has been associated with many health benefits including the prevention of cancer and heart disease. Theaflavins are the major bioactive polyphenols present in black tea. Unfortunately, limited information is available on their biotransformation. In the present study, we investigated the metabolic fate of Theaflavin 3,3′-digallate (TFDG), one of the most abundant and bioactive Theaflavins, in mouse fecal samples using liquid chromatography/electrospray ionization tandem mass spectrometry by analyzing the MSn (n = 1–3) spectra. Four metabolites Theaflavin, Theaflavin 3-gallate, Theaflavin 3′-gallate, and gallic acid were identified as the major mouse fecal metabolites of TFDG. Glucuronidated and sulfated, instead of methylated metabolites of Theaflavin 3-gallate, Theaflavin 3′-gallate, and TFDG were detected and identified as the minor mouse fecal metabolites of TFDG. Our results indicate that TFDG can be degraded in mice. Further studies on the formation of those metabolites in TFDG-treated mice in germ-free conditions are warranted. To our knowledge, this is the first report on the biotransformation of TFDG in mice.
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ENZYMATIC SYNTHESIS OF TheaflavinS AND EPITHEAFLAVIC ACID FROM TEA CATECHINS AND THEIR ANTIOXIDANT ACTIVITY
Journal of Food Lipids, 2004Co-Authors: Jim Woo Jhoo, Shengmin Sang, Guor Jien Wei, Tung-ching Lee, Robert T. RosenAbstract:A number of in vitro and in vivo studies have demonstrated that black tea polyphenols have significant biological activities, including antioxidant, antiinflammatory and anticancer activity. The Theaflavins have received attention as one of responsible components for biological activities of black tea. However, little information is available for the biological activity of individual Theaflavins and minor components in black tea. In the present study, Theaflavins and epitheqflavic acid were synthesized from their parent flavan-3-ols catechins using an enzymatic oxidation method and employing crude polyphenol oxidase from banana fruit. The compounds were isolated using column chromatographic methods, and their structures confirmed by 1H-NMR and APCI-MS. The peroxyl radical scavenging activities of Theaflavins and epitheaflavic acids were measured using a modified ORAC method. The results indicated that Theaflavins have higher peroxyl radical scavenging activity than EGCG. The hierarchy of radical scavenging activity of Theaflavins, epitheaflavic acid and related compounds were in the order of: Theaflavin-3, 3′-digallate ∼ theflavin-3-gallate ∼ Theaflavin-3′-gallate ∼ Theaflavin > epitheaflavic acid > EGCG > purpurogallin.
Chung S Yang - One of the best experts on this subject based on the ideXlab platform.
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Theaflavin 3 3 digallate induces epidermal growth factor receptor downregulation
Molecular Carcinogenesis, 2006Co-Authors: Hideya Mizuno, Chung S Yang, Yong Yeon Cho, Feng Zhu, Ann M Bode, Zigang DongAbstract:Black tea is one of the most popular beverages worldwide and especially in Western nations. Theaflavins, a mixture of Theaflavin (TF-1), Theaflavin-3-gallate (TF-2a), Theaflavin-3'-gallate (TF-2b), and Theaflavin-3,3'-digallate (TF-3) are the major components of black tea. Among these black tea components, Theaflavin is generally considered to be the more effective component for the inhibition of carcinogenesis. Recently, TF-3 has been shown to have an antiproliferative effect on tumor cells, but the mechanism is not clear. In this study, we showed that TF-3-induced internalization and downregulation of the epidermal growth factor receptor (EGFR). These results suggested that TF-3 induces EGFR endocytosis and degradation. We further showed that TF-3 stimulated EGFR ubiquitination and tyrosine kinase activation. Interestingly, TF-3-induced EGFR downregulation is inhibited by the proteasome inhibitor, MG132, but not by the EGFR-specific receptor tyrosine kinase inhibitor, AG1478. Furthermore, pretreatment with TF-3 inhibited EGF-induced EGFR autophosphorylation, ERKs phosphorylation and AP-1 activation in JB6 Cl41 cells. In addition, TF-3 inhibited EGF-induced anchorage-independent cell transformation. Overall, our results indicate that TF-3 might exert chemopreventive effects through the downregulation of the EGFR.
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delivery of tea polyphenols to the oral cavity by green tea leaves and black tea extract
Cancer Epidemiology Biomarkers & Prevention, 2004Co-Authors: Joshua D Lambert, Pius Maliakal, Saileta Prabhu, Xiaofeng Meng, Chitang Ho, Hong Lu, Chung S YangAbstract:Catechins and Theaflavins, polyphenolic compounds derived from tea ( Camellia sinensis , fam. Theaceae), have been reported to have a wide range of biological activities including prevention of tooth decay and oral cancer. The present study was undertaken to determine the usefulness of green tea leaves and black tea extract for the delivery of catechins and Theaflavins to the oral cavity. After holding either green tea leaves (2 g) or brewed black tea (2 g of black tea leaves in 100 ml) in the mouth for 2–5 min and thoroughly rinsing the mouth, high concentrations of catechins ( C max = 131.0–2.2 μm) and Theaflavins ( C max = 1.8–0.6 μm) were observed in saliva in the 1st hour. Whereas there was significant interindividual variation in the peak levels of catechins and Theaflavins, the overall kinetic profile was similar, with t 1/2 = 25–44 min and 49–76 min for catechins and Theaflavins, respectively (average coefficient of variation in t 1/2 was 23.4%). In addition to the parent catechin and Theaflavin peaks, five unidentified peaks were also observed in saliva after black tea treatment. Hydrolysis of Theaflavin gallates, apparently by salivary esterases, was observed in vitro and in vivo . These results indicate that tea leaves can be used as a convenient, slow-release source of catechins and Theaflavins and provide information for the possible use of tea in the prevention of oral cancer and dental caries.
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theadibenzotropolone a a new type pigment from enzymatic oxidation of epicatechin and epigallocatechin gallate and characterized from black tea using lc ms ms
Tetrahedron Letters, 2002Co-Authors: Shengmin Sang, Chung S Yang, Xiaofeng Meng, Robert T. Rosen, Shiying Tian, Ruth E Stark, Chitang HoAbstract:Abstract Theaflavins and thearubigins are major pigments of black tea. In the course of studies on the oxidation mechanism of tea polyphenols, a new type of tea pigment, theadibenzotropolone A, together with Theaflavin 3-gallate were formed by the reaction of (−)-epicatechin (EC) and (−)-epigallocatechin gallate (EGCG) with horseradish peroxidase in the presence of H 2 O 2 . The structure of theadibenzotropolone A was elucidated on the basis of MS and 2D NMR spectroscopic analyses. The observation that galloyl ester groups of Theaflavins can be oxidized to form dibenzotropolone skeletons strongly implied that this type of oxidation as an important pathway to extend the molecular size of thearubigins. The existence of this compound in black tea was characterized by LC/ESI-MS/MS. Theadibenzotropolone A is the first Theaflavin type trimer of catechins in black tea.
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effects of purified green and black tea polyphenols on cyclooxygenase and lipoxygenase dependent metabolism of arachidonic acid in human colon mucosa and colon tumor tissues
Biochemical Pharmacology, 2001Co-Authors: Jungil Hong, Theresa J Smith, David A. August, Chitang Ho, Chung S YangAbstract:Abstract The effects of green and black tea polyphenols on cyclooxygenase (COX)- and lipoxygenase (LOX)-dependent arachidonic acid metabolism in normal human colon mucosa and colon cancers were investigated. At a concentration of 30 μg/mL, (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), and (-)-epicatechin-3-gallate (ECG) from green tea and Theaflavins from black tea inhibited LOX-dependent activity by 30–75%. The formation of 5-, 12-, and 15-LOX metabolites was inhibited to a similar extent. Tea polyphenols also inhibited COX-dependent arachidonic acid metabolism in microsomes from normal colon mucosa, with ECG showing the strongest inhibition. The formation of thromboxane (TBX) and 12-hydroxyheptadecatrienoic acid (HHT) was decreased to a greater extent than other metabolites. The inhibitory effects of tea polyphenols on COX activity, however, were less pronounced in tumor microsomes than in normal colon mucosal microsomes. Theaflavins strongly inhibited the formation of TBX and HHT, but increased the production of prostaglandin E 2 (PGE 2 ) in tumor microsomes. The enhancing effect of Theaflavins on PGE 2 production was related to the COX-2 level in the microsomes. Although Theaflavin inhibited ovine COX-2, its activity in the formation of PGE 2 was stimulated by Theaflavin when ovine COX-2 was mixed with microsomes, suggesting that Theaflavin affects the interaction of COX-2 with other microsomal factors (e.g. PGE synthase). The present results indicate that tea polyphenols can affect arachidonic acid metabolism in human colon mucosa and colon tumors, and this action may alter the risk for colon cancer in humans.
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inhibition of activator protein 1 activity and cell growth by purified green tea and black tea polyphenols in h ras transformed cells structure activity relationship and mechanisms involved
Cancer Research, 1999Co-Authors: Jee Y Chung, Zigang Dong, Xiaofeng Meng, Chuanshu Huang, Chung S YangAbstract:ras gene mutation, which perpetually turns on the growth signal transduction pathway, occurs frequently in many cancer types. The mouse epidermal JB6 cell line has been transfected with a mutant H-ras gene to mimic carcinogenesis in vitro. These transformed cells (30.7b Ras 12) are able to grow in soft agar, exhibiting anchorage independence and high endogenous activator protein 1 (AP-1) activity, which can be detected by a stable AP-1 luciferase reporter. The present study investigated the ability of different pure green and black tea polyphenols to inhibit this ras signaling pathway. The major green tea polyphenols (catechins), (−)-epigallocatechin-3-gallate (EGCG), (−)-epigallocatechin, (−)-epicatechin-3-gallate, (−)-epicatechin, and their epimers, and black tea polyphenols, Theaflavin, Theaflavin-3-gallate, Theaflavin-3′-gallate, and Theaflavin-3,3′-digallate (TFdiG), were compared with respect to their ability to inhibit the growth of 30.7b Ras 12 cells and AP-1 activity. All of the tea polyphenols except (−)-epicatechin showed strong inhibition of cell growth and AP-1 activity. Among the catechins, both the galloyl structure on the B ring and the gallate moiety contributed to the growth inhibition and AP-1 activity; the galloyl structure appeared to have a stronger effect on the inhibitory action than the gallate moiety. The epimers of the catechins showed similar inhibitory effects on AP-1 activity. The addition of catalase to the incubation of the cells with EGCG or TFdiG did not prevent the inhibitory effect on AP-1 activity, suggesting that H2O2 does not play a significant role in the inhibition by tea polyphenols. Both EGCG and TFdiG inhibited the phosphorylation of p44/42 (extracellular signal-regulated kinase 1 and 2) and c-jun without affecting the levels of phosphorylated-c-jun-NH2-terminal kinase. TFdiG inhibited the phosphorylation of p38, but EGCG did not. EGCG lowered the level of c-jun, whereas TFdiG decreased the level of fra-1. These results suggest that tea polyphenols inhibited AP-1 activity and the mitogen-activated protein kinase pathway, which contributed to the growth inhibition; however, different mechanisms may be involved in the inhibition by catechins and Theaflavins.
Huadong Chen - One of the best experts on this subject based on the ideXlab platform.
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The Microbiota Is Essential for the Generation of Black Tea Theaflavins-Derived Metabolites
2016Co-Authors: Huadong Chen, Javier Rivera Guzman, Nicholas D. Gillitt, Salam A. Ibrahim, Saeed Hayek, Shengmin SangAbstract:Background: Theaflavins including Theaflavin (TF), Theaflavin-3-gallate (TF3G), Theaflavin-39-gallate (TF39G), and Theaflavin-3,39-digallate (TFDG), are the most important bioactive polyphenols in black tea. Because of their poor systemic bioavailability, it is still unclear how these compounds can exert their biological functions. The objective of this study is to identify the microbial metabolites of Theaflavins in mice and in humans. Methods and Findings: In the present study, we gavaged specific pathogen free (SPF) mice and germ free (GF) mice with 200 mg/kg TFDG and identified TF, TF3G, TF39G, and gallic acid as the major fecal metabolites of TFDG in SPF mice. These metabolites were absent in TFDG- gavaged GF mice. The microbial bioconversion of TFDG, TF3G, and TF39G was also investigated in vitro using fecal slurries collected from three healthy human subjects. Our results indicate that TFDG is metabolized to TF, TF3G, TF39G, gallic acid, and pyrogallol by human microbiota. Moreover, both TF3G and TF39G are metabolized to TF, gallic acid, and pyrogallol by human microbiota. Importantly, we observed interindividual differences on the metabolism rate of gallic acid to pyrogallol among the three human subjects. In addition, we demonstrated that Lactobacillus plantarum 299v and Bacillus subtilis have the capacity to metabolize TFDG. Conclusions: The microbiota is important for the metabolism of Theaflavins in both mice and humans. The in vivo functiona
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The microbiota is essential for the generation of black tea Theaflavins-derived metabolites.
PloS one, 2012Co-Authors: Huadong Chen, Saeed A. Hayek, Javier Rivera Guzman, Nicholas D. Gillitt, Salam A. Ibrahim, Christian Jobin, Shengmin SangAbstract:Background Theaflavins including Theaflavin (TF), Theaflavin-3-gallate (TF3G), Theaflavin-3′-gallate (TF3′G), and Theaflavin-3,3′-digallate (TFDG), are the most important bioactive polyphenols in black tea. Because of their poor systemic bioavailability, it is still unclear how these compounds can exert their biological functions. The objective of this study is to identify the microbial metabolites of Theaflavins in mice and in humans.
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structural identification of Theaflavin trigallate and tetragallate from black tea using liquid chromatography electrospray ionization tandem mass spectrometry
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Huadong Chen, Kelly L Shurlknight, Tinchung Leung, Shengmin SangAbstract:Black tea contains two major pigments, Theaflavins and thearubigins. These polyphenols have been associated with certain health benefits including prevention of heart disease and cancer. Elucidating and characterizing the structural aspects of thearubigins, the most abundant pigment in black tea, has been a challenge for many years. Therefore further studies of black tea polyphenols must be conducted in effort to solve this thearubigin dispute. In the present study, black tea extract was found to possess Theaflavin trigallate and tetragallate by means of liquid chromatography/electrospray ionization mass spectrometry. These structures were confirmed by analysis of the MS(n) (n = 1-4) spectra and comparison of the MS/MS spectra of the product ions to the MS/MS spectra of authentic (-)-epigallocatechin-3-gallate, (-)-epicatechin-3-gallate and Theaflavin-3,3'-digallate. To our knowledge, this is the first report to confirm the presence of Theaflavin trigallate and tetragallate in black tea.
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structural identification of mouse fecal metabolites of Theaflavin 3 3 digallate using liquid chromatography tandem mass spectrometry
Journal of Chromatography A, 2011Co-Authors: Huadong Chen, Nicholas D. Gillitt, Christian Jobin, Tiffany A Parks, Xiaoxin Chen, Shengmin SangAbstract:Black tea consumption has been associated with many health benefits including the prevention of cancer and heart disease. Theaflavins are the major bioactive polyphenols present in black tea. Unfortunately, limited information is available on their biotransformation. In the present study, we investigated the metabolic fate of Theaflavin 3,3′-digallate (TFDG), one of the most abundant and bioactive Theaflavins, in mouse fecal samples using liquid chromatography/electrospray ionization tandem mass spectrometry by analyzing the MSn (n = 1–3) spectra. Four metabolites Theaflavin, Theaflavin 3-gallate, Theaflavin 3′-gallate, and gallic acid were identified as the major mouse fecal metabolites of TFDG. Glucuronidated and sulfated, instead of methylated metabolites of Theaflavin 3-gallate, Theaflavin 3′-gallate, and TFDG were detected and identified as the minor mouse fecal metabolites of TFDG. Our results indicate that TFDG can be degraded in mice. Further studies on the formation of those metabolites in TFDG-treated mice in germ-free conditions are warranted. To our knowledge, this is the first report on the biotransformation of TFDG in mice.
Jenkun Lin - One of the best experts on this subject based on the ideXlab platform.
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inhibition of 12 o tetradecanoylphorbol 13 acetate induced inflammatory skin edema and ornithine decarboxylase activity by Theaflavin 3 3 digallate in mouse
Nutrition and Cancer, 2002Co-Authors: Yu Chih Liang, De Cheng Tsai, Shoeiyn Linshiau, Chieh Fu Chen, Jenkun LinAbstract:Among black tea polyphenols, Theaflavins were generally considered to be the most effective in cancer chemoprevention. In this study, we examined the inhibitory effects of black tea polyphenols, including Theaflavin (TF-1), a mixture (TF-2) of Theaflavin-3-gallate and Theaflavin-3′-gallate, Theaflavin-3,3′-digallate (TF-3), and the green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema and ornithine decarboxylase (ODC) activity. Topical application of these polyphenols onto the mouse resulted in inhibition of TPA-induced ear edema and skin epidermal ODC activity. The inhibitory order was as follows: TF-3 > TF-2 ≃ EGCG > TF-1. Western and Northern blots indicated that TF-3 significantly reduced the protein and mRNA levels of ODC in TPA-treated mouse skin and NIH 3T3 cells, whereas EGCG showed less activity. EGCG and TF-3 were able to inhibit the ODC enzyme activity in vitro. Furthermore, TF-3 also significantly reduced the basal promoter activ...
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suppression of extracellular signals and cell proliferation by the black tea polyphenol Theaflavin 3 3 digallate
Carcinogenesis, 1999Co-Authors: Yu Chih Liang, Shoeiyn Linshiau, Yen Chou Chen, Yuli Lin, Jenkun LinAbstract:Previous studies in our laboratory have shown that the major green tea polyphenol, (-)-epigallocatechin-3-gallate (EGCG), suppressed autophosphorylation of epidermal growth factor (EGF) receptor induced by EGF in human A431 epidermoid carcinoma cells. In this study, we examined the inhibitory effects of black tea polyphenols, including Theaflavin (TF-1), a mixture (TF-2) of Theaflavin-3-gallate (TF-2a) and Theaflavin-3'-gallate (TF-2b), Theaflavin-3,3'-digallate (TF-3) and the thearubigin fraction on the autophosphorylation of the EGF and PDGF receptors in A431 cells and mouse NIH3T3 fibroblast cells, respectively. First, we examined the effects of these polyphenols on the proliferation of A431 and NIH3T3 cells. Both EGCG and TF-3 strongly inhibited the proliferation of A431 and NIH3T3 cells more than the other Theaflavins did. In cultured cells with pre-treatment of tea polyphenol, TF-3 was stronger than EGCG on the reduction of EGF receptor and PDGF receptor autophosphorylation induced by EGF and PDGF, respectively. Other Theaflavins slightly reduced the autophosphorylation of the EGF and PDGF receptors; furthermore, TF-3 could reduce autophosphorylation of the EGF receptor (or PDGF receptor) even with co-treatment with EGF (or PDGF) and TF-3, but EGCG was inactive under these conditions. In addition, TF-3 was stronger than EGCG in blocking EGF binding to its receptor. These results suggest that not only the green tea polyphenol, EGCG, but also the black tea polyphenol, TF-3, have an antiproliferative activity on tumor cells, and the molecular mechanisms of antiproliferation may block the growth factor binding to its receptor and thus suppress mitogenic signal transduction.
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Theaflavin 3 3 digallate from black tea blocks the nitric oxide synthase by down regulating the activation of nf κb in macrophages
European Journal of Pharmacology, 1999Co-Authors: Yuli Lin, Shoeiyn Linshiau, Shuhuei Tsai, Jenkun LinAbstract:Abstract Nitric oxide (NO) plays an important role in inflammation and also in multiple stages of carcinogenesis. We investigated the effects of various tea polyphenols, including Theaflavin, a mixture of Theaflavin-3-gallate and Theaflavin-3′-gallate, Theaflavin-3,3′-digallate, thearubigin, and (−)-epigallocatechin-3-gallate on the induction of NO synthase in lipopolysaccharide-activated murine macrophages, RAW 264.7 cells. Theaflavin-3,3′-digallate was found to be stronger than (−)-epigallocatechin-3-gallate in inhibiting NO generation and inducible NO synthase protein in activated macrophages, while Theaflavin, a mixture of Theaflavin-3-gallate and Theaflavin-3′-gallate and thearubigin were less effective. Inhibition of NO production was observed when cells were cotreated with Theaflavin-3,3′-digallate and lipopolysaccharide. Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses demonstrated that significantly reduced 130-kDa protein and mRNA levels of inducible NO synthase were expressed in lipopolysacchride-activated macrophages with Theaflavin-3,3′-digallate, compared to those without Theaflavin-3,3′-digallate. Electrophoretic mobility shift assay (EMSA) indicated that Theaflavin-3,3′-digallate blocked the activation of nuclear factor κB (NF-κB), a transcription factor necessary for inducible NO synthase induction. Theaflavin-3,3′-digallate also blocked phosphorylation of IκB from cytosolic fraction and reduced lipopolysacchride-induced nuclear accumulation of transcription factor NF-κB p65 and p50 subunits. These results suggest that Theaflavin-3,3′-digallate decreases the protein levels of inducible NO synthase by reducing the expression of inducible NO synthase mRNA, and the reduction could be via preventing the activation of NF-κB, thereby inhibiting the induction of inducible NO synthase transcription. It was also demonstrated that the gallic acid moiety of Theaflavin-3,3′-digallate is essential for their potent anti-inflammation activity.
Chitang Ho - One of the best experts on this subject based on the ideXlab platform.
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inhibitory effects of black tea Theaflavin derivatives on 12 o tetradecanoylphorbol 13 acetate induced inflammation and arachidonic acid metabolism in mouse ears
Molecular Nutrition & Food Research, 2006Co-Authors: Moutuan Huang, Divya Ramji, Chih Yu Lo, Geetha Ghai, Slavik Dushenkov, Chitang HoAbstract:Tea has been shown to possess several health beneficial properties primarily due to its polyphenolic content. The major polyphenolic compounds in black tea leaves are Theaflavins (TFs) formed by oxi- dative coupling of catechins in tea leaves during its processing. In this paper, we report the characte- rization of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear inflammatory model and the inhibitory effects of major black tea TFs derivatives on this inflammation. In addition, the effect on inflammatory biomarkers, such as proinflammatory cytokines and arachidonic acid metabolites, are reported as well. A single topical application of TPA to ears of CD-1 mice induced a time- and dose-dependent increase in edema as well as formation of proinflammatory cytokine proteins inter- leukin-1b (IL-1b) and interleukin-6 (IL-6) in mouse ears. A single topical application of equimolar of black tea constituents (TF, Theaflavin-3-gallate, Theaflavin-39-gallate, and Theaflavin-3,39-digallate) strongly inhibited TPA-induced edema of mouse ears. Application of TFs mixture to mouse ears 20 min prior to each TPA application once a day for 4 days inhibited TPA-induced persistent inflam- mation, as well as TPA-induced increase in IL-1b and IL-6 protein levels. TFs also inhibited arachi- donic acid (AA) metabolism via both cyclooxygenase (COX) and lipoxygenase pathways. This obser- vation was substantiated by decreased amounts of AA metabolites prostaglandin E2 (PGE2) and leuko- triene B4 (LTB4) levels. Combined application of TF and sulindac, a nonsteroidal anti-inflammatory drug resulted a significant synergetic anti-inflammatory effect. Oral administration of TFs or the hot water extract of black tea leaves also significantly inhibited TPA-induced edema in mouse ears. In conclusion, proinflammatory cytokines, IL-1b and IL-6, as well as the intermediated metabolites of AA, PGE2, and LTB4 are good biomarkers for inflammation. Black tea constituents, TF and its deriv- atives, had strongly anti-inflammatory activity in vivo which may be due to their ability to inhibit AA metabolism via lipoxygenase and COX pathways.
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phenolic compounds in foods and natural health products
Phenolic compounds in foods and natural health products., 2005Co-Authors: Fereidoon Shahidi, Chitang HoAbstract:Phenolic and polyphenolic compounds in foods and natural nutraceutical products represent the most widely distributed plant secondary metabolites exerting their beneficial effects as free radical scavengers and chelators of pro-oxidant metals and thus preventing low-density lipoprotein oxidation and DNA strand scission or enhancing immune function. Phenolic compounds have been shown to control certain types of cancer, cardiovascular disease and the process of ageing. This book reports the chemistry and analysis of phenolic compounds in various foods such as wheat bans, canola hulls, blueberry leaf, sesame, edible oil seeds and honeybush tea. Extensive coverage was given to green and black tea. The chemistry of the production of black tea Theaflavins, the action mechanisms of Theaflavins on anti-tumor effects, the anti-inflammatory activity of Theaflavin, the bioavailability and biotransformation of tea polyphenols, and a practical example on the use of tea catechin as food antioxidant and antibacterial were presented. Anticancer effects of other polyphenols from apple, cranberry and spices are also discussed.
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delivery of tea polyphenols to the oral cavity by green tea leaves and black tea extract
Cancer Epidemiology Biomarkers & Prevention, 2004Co-Authors: Joshua D Lambert, Pius Maliakal, Saileta Prabhu, Xiaofeng Meng, Chitang Ho, Hong Lu, Chung S YangAbstract:Catechins and Theaflavins, polyphenolic compounds derived from tea ( Camellia sinensis , fam. Theaceae), have been reported to have a wide range of biological activities including prevention of tooth decay and oral cancer. The present study was undertaken to determine the usefulness of green tea leaves and black tea extract for the delivery of catechins and Theaflavins to the oral cavity. After holding either green tea leaves (2 g) or brewed black tea (2 g of black tea leaves in 100 ml) in the mouth for 2–5 min and thoroughly rinsing the mouth, high concentrations of catechins ( C max = 131.0–2.2 μm) and Theaflavins ( C max = 1.8–0.6 μm) were observed in saliva in the 1st hour. Whereas there was significant interindividual variation in the peak levels of catechins and Theaflavins, the overall kinetic profile was similar, with t 1/2 = 25–44 min and 49–76 min for catechins and Theaflavins, respectively (average coefficient of variation in t 1/2 was 23.4%). In addition to the parent catechin and Theaflavin peaks, five unidentified peaks were also observed in saliva after black tea treatment. Hydrolysis of Theaflavin gallates, apparently by salivary esterases, was observed in vitro and in vivo . These results indicate that tea leaves can be used as a convenient, slow-release source of catechins and Theaflavins and provide information for the possible use of tea in the prevention of oral cancer and dental caries.
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theadibenzotropolone a a new type pigment from enzymatic oxidation of epicatechin and epigallocatechin gallate and characterized from black tea using lc ms ms
Tetrahedron Letters, 2002Co-Authors: Shengmin Sang, Chung S Yang, Xiaofeng Meng, Robert T. Rosen, Shiying Tian, Ruth E Stark, Chitang HoAbstract:Abstract Theaflavins and thearubigins are major pigments of black tea. In the course of studies on the oxidation mechanism of tea polyphenols, a new type of tea pigment, theadibenzotropolone A, together with Theaflavin 3-gallate were formed by the reaction of (−)-epicatechin (EC) and (−)-epigallocatechin gallate (EGCG) with horseradish peroxidase in the presence of H 2 O 2 . The structure of theadibenzotropolone A was elucidated on the basis of MS and 2D NMR spectroscopic analyses. The observation that galloyl ester groups of Theaflavins can be oxidized to form dibenzotropolone skeletons strongly implied that this type of oxidation as an important pathway to extend the molecular size of thearubigins. The existence of this compound in black tea was characterized by LC/ESI-MS/MS. Theadibenzotropolone A is the first Theaflavin type trimer of catechins in black tea.
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effects of purified green and black tea polyphenols on cyclooxygenase and lipoxygenase dependent metabolism of arachidonic acid in human colon mucosa and colon tumor tissues
Biochemical Pharmacology, 2001Co-Authors: Jungil Hong, Theresa J Smith, David A. August, Chitang Ho, Chung S YangAbstract:Abstract The effects of green and black tea polyphenols on cyclooxygenase (COX)- and lipoxygenase (LOX)-dependent arachidonic acid metabolism in normal human colon mucosa and colon cancers were investigated. At a concentration of 30 μg/mL, (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), and (-)-epicatechin-3-gallate (ECG) from green tea and Theaflavins from black tea inhibited LOX-dependent activity by 30–75%. The formation of 5-, 12-, and 15-LOX metabolites was inhibited to a similar extent. Tea polyphenols also inhibited COX-dependent arachidonic acid metabolism in microsomes from normal colon mucosa, with ECG showing the strongest inhibition. The formation of thromboxane (TBX) and 12-hydroxyheptadecatrienoic acid (HHT) was decreased to a greater extent than other metabolites. The inhibitory effects of tea polyphenols on COX activity, however, were less pronounced in tumor microsomes than in normal colon mucosal microsomes. Theaflavins strongly inhibited the formation of TBX and HHT, but increased the production of prostaglandin E 2 (PGE 2 ) in tumor microsomes. The enhancing effect of Theaflavins on PGE 2 production was related to the COX-2 level in the microsomes. Although Theaflavin inhibited ovine COX-2, its activity in the formation of PGE 2 was stimulated by Theaflavin when ovine COX-2 was mixed with microsomes, suggesting that Theaflavin affects the interaction of COX-2 with other microsomal factors (e.g. PGE synthase). The present results indicate that tea polyphenols can affect arachidonic acid metabolism in human colon mucosa and colon tumors, and this action may alter the risk for colon cancer in humans.
