- Accumulation of epigallocatechin quinone dimers during tea fermentation and formation of theasinensins
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Production and accumulation of catechin dimer quinones during tea fermentation were chemically confirmed for the first time by trapping as phenazine derivatives. Direct treatment of the fermented tea leaves with o-phenylenediamine yielded five phenazine derivatives (8-12) of o-quinones of an epigallocatechin dimer and its galloyl esters (13-16), in which two flavan units were linked at the B-rings through a C-C bond. Atrop isomerism of the biphenyl bonds was shown to be the R configuration, suggesting that the o-quinone dimers were generated by stereoselective coupling of monomeric quinones. The total concentration of the phenazine derivatives in the o-phenylenediamine-treated tea leaves was higher than that of theaflavins. In contrast, phenazine derivatives of monomeric quinones of epigallocatechin were not isolated. When the fermented tea leaves were heated, the quinone dimers were converted to theasinensins, which are constituents of black tea, suggesting that theasinensins are generated by reduction of the quinone dimers during the heating and drying steps in black tea manufacturing.
- Tanaka, Takashi,Mine, Chie,Watarumi, Sayaka,Fujioka, Toshihiro,Mihashi, Kunihide,Zhang, Ying-Jun,Kouno, Isao
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Read Online
- Structures of two new oxidation products of green tea polyphenols generated by model tea fermentation
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To clarify the oxidation mechanism of green tea catechins during tea fermentation, pure catechins were oxidized with a catechin-free homogenate of tea leaf. Oxidation of a mixture of (-)-epicatechin and (-)-epigallocatechin yielded a new metabolite, named dehydrotheaflavin, produced by the oxidation of a benzotropolone moiety of the black tea pigment theaflavin. Similar oxidation of a mixture of (-)-epicatechin and (-)-epigallocatechin 3-O-gallate afforded a new dimer of (-)-epigallocatechin 3-O-gallate, which was generated by the oxidation and cycloaddition of two pyrogallol rings. Structures were determined by spectroscopic method, and the oxidation mechanisms for the formation of the products were proposed.
- Tanaka, Takashi,Mine, Chie,Kouno, Isao
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Read Online
- Nonenzymatic Biomimetic Synthesis of Black Tea Pigment Theaflavins
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Theaflavins are reddish-orange black tea pigments with a benzotropolone chromophore, and their various biological activities have been reported. Theaflavins are produced by oxidative coupling between catechol-type and pyrogallol-type catechins via bicyclo[3.2.1]octane-type intermediates. In this study, a new method for nonenzymatic biomimetic synthesis of theaflavins was developed using the DPPH radical as an oxidizing agent.
- Matsuo, Yosuke,Oowatashi, Ryosuke,Saito, Yoshinori,Tanaka, Takashi
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supporting information
p. 2505 - 2508
(2017/10/06)
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- CATALYST FOR SYNTHESIZING THEAFLAVINS AND METHOD FOR SYNTHESIZING THEAFLAVINS
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The objective/problem addressed by the present invention is to provide a novel technique pertaining to theaflavins synthesis. The present invention pertains to: a theaflavins synthesis catalyst characterized in having a base comprising an inorganic material, and metal nanoparticles anchored to the base, said particles measuring 0.5-100 nm in diameter; and a theaflavins synthesis method in which the catalyst is used.
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Paragraph 0076; 0077; 0087; 0088
(2017/07/01)
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- Syntheses of methylated catechins and theaflavins using 2-nitrobenzenesulfonyl group to protect and deactivate phenol
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An efficient and versatile synthetic method for labile polyphenols was established using 2-nitrobenzenesulfonate (Ns) as a protecting group for phenol. This methodology provides regio-and stereoselective access to a range of methylated catechins, such as methylated epigallocatechin gallates, that are not readily available from natural sources. In addition, biomimetic synthesis of theaflavins from catechins was accomplished using Ns protection to minimize undesired side reactions of electron-rich aromatic rings during oxidation, enabling construction of the complex benzotropolone core in a single-step oxidative coupling reaction. Availability of these compounds will aid detailed structure-biological activity relationship studies of catechins.
- Asakawa, Tomohiro,Kawabe, Yusuke,Yoshida, Atsushi,Aihara, Yoshiyuki,Manabe, Tamiko,Hirose, Yoshitsugu,Sakurada, Asuka,Inai, Makoto,Hamashima, Yoshitaka,Furuta, Takumi,Wakimoto, Toshiyuki,Kan, Toshiyuki
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p. 299 - 312
(2016/05/09)
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- Specificity of tyrosinase-catalyzed synthesis of theaflavins
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This study kinetically characterized the mechanism of the enzymatic synthesis of theaflavins (TFs) from catechins by mushroom tyrosinase (EC 1.14.18.1). In reactions containing one of four catechins, (-)-epicatechin (EC), (-)-epigallocatechin (EGC), and their galloylated forms (ECg and EGCg), they were oxidized by tyrosinase with apparent KM values of 3.78, 5.55, 0.80, and 3.05 mM, respectively, and with different consumption rates, of which EC was more than four times higher than those of the others. In reactions with binary combinations of catechins with tyrosinase, the synthesis of TF1 from EC and EGC occurred most efficiently, while the yields of mono- and di-galloylated TFs, TF2A, TF2B, and TF3, were low. Time-dependent changes in concentrations of the reactants suggested that the enzymatic oxidation of catechins and the subsequent non-enzymatic coupling redox reaction between the quinone derived from EC or ECg and the intact pyrogallol-type catechin (EGC or EGCg) proceeded concurrently. The latter reaction induced the rapid decrease of EGC and EGCg and it was remarkable for EGCg. So the efficiency of condensation of a pair of quinones from catechol- and pyrogallol-type catechins is restricted, critically influencing the yield of TFs. Using green tea extracts as mixtures of the four substrate catechins, tyrosinase produced TF1 most abundantly. Furthermore, a remarkable enhancement of production of TF2A and TF2B as well as TF1 was observed, when the initial concentration of EGCg was low. These results suggest that the catechin composition has an impact on yields of TFs.
- Narai-Kanayama, Asako,Kawashima, Aya,Uchida, Yuuka,Kawamura, Miho,Nakayama, Tsutomu
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p. S452 - S458
(2018/04/05)
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- Oxidation mechanism of black tea pigment theaflavin by peroxidase
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A large number of black tea polyphenols remain uncharacterized because of the complexity of catechin oxidation reactions that occur during tea fermentation. In the course of our studies on black tea polyphenols, we examined the enzymatic degradation of theaflavins, which are black tea pigments having a benzotropolone chromophore. Oxidation of theaflavin with peroxidase afforded a new product named theacoumarin A together with known pigment theanaphthoquinone. The structure of the new compound was determined by spectroscopic examination and a production mechanism via theanaphthoquinone is proposed.
- Kusano, Rie,Matsuo, Yosuke,Saito, Yoshinori,Tanaka, Takashi
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p. 5099 - 5102
(2015/08/06)
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- Synthesis of theaflavins with Camellia sinensis cell culture and inhibition of increase in blood sugar values in high-fat diet mice subjected to sucrose or glucose loading
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Theaflavin and its galloyl esters are major polyphenolic pigments of black tea. We compared the efficiency of a variety of oxidizing enzyme systems to synthesize theaflavin and its galloyl esters. Camellia sinensis cell culture efficiently synthesized theaflavin from epicatechin and epigallocatechin with 70% yield and 100% conversion in 4 min. In an administration experiment performed in mice, theaflavin inhibited the increase blood glucose levels in mice that were fed a high-fat diet and subjected to glucose or sucrose loading in mice.
- Takemoto, Masumi,Takemoto, Hiroaki,Sakurada, Asuka
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p. 5038 - 5040
(2015/02/02)
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- Synthesis of Theaflavins via Biomimetic Oxidative Coupling Reactions
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Biomimetic synthesis of theaflavins from catechins was accomplished by using 2-nitrobenzenesulfonyl (Ns) as a protecting group for phenols to minimize undesired side reactions of the electron-rich aromatic rings. This enabled the construction of the complex benzotropolone core in a single-step oxidative coupling reaction. Georg Thieme Verlag Stuttgart · New York.
- Kawabe, Yusuke,Aihara, Yoshiyuki,Hirose, Yoshitsugu,Sakurada, Asuka,Yoshida, Atsushi,Inai, Makoto,Asakawa, Tomohiro,Hamashima, Yoshitaka,Kan, Toshiyuki
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supporting information
p. 479 - 482
(2013/04/10)
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- Reaction of the black tea pigment theaflavin during enzymatic oxidation of tea catechins
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Degradation of the black tea pigment theaflavin was examined in detail. Enzymatic oxidation of a mixture of epigallocatechin and epicatechin initially produced theaflavin, while prolonged reaction decreased the product. Addition of ethanol to the reaction mixture at the point when theaflavin began to decrease afforded four new products, together with theanaphthoquinone, a known oxidation product of theaflavin. The structures of the new products were determined by spectroscopic methods. One of the products was an ethanol adduct of a theanaphthoquinone precursor, and this reacted with theaflavin to give two further products. A product generated by coupling of theaflavin with epicatechin quinone was also obtained. The structures of the products indicate that oxidation and coupling with quinones are key reactions in the degradation of theaflavins. The degradation of theaflavin probably contributes to production of thearubigins.
- Li, Yan,Shibahara, Akane,Matsuo, Yosuke,Tanaka, Takashi,Kouno, Isao
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experimental part
p. 33 - 39
(2010/04/06)
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- Benzotropolone derivatives and modulation of inflammatory response
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The present invention provides novel benzotropolone derivatives represented by the general formula: 1 including neotheaflavate B and EGCGCa. The benzotropolone derivatives of the present invention are effective antioxidant and anti-inflammatory agents. The present invention also provides novel method of synthesizing benzotropolone compounds in high yields and method of treating inflammatory conditions using benzotropolone containing compounds.
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Page/Page column 9
(2008/06/13)
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- Stability of black tea polyphenol, theaflavin, and identification of theanaphthoquinone as its major radical reaction product
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In the current study, we have focused on isolation and detection of major radical oxidation products from theaflavin in order to better understand antioxidation mechanisms of this compound. Theanaphthoquinone was identified as a major oxidation product of theaflavin from two different oxidant model systems: DPPH and peroxidase/hydrogen peroxide. This result indicated that the benzotropolone moiety in theaflavin may play an important role in its antioxidant properties. The stability of theaflavin was studied in varying pH solutions: simulated gastric juice and buffer solutions of pH 5.5, pH 7.4, and pH 8.5. The results indicated that theaflavin is unstable in alkaline conditions, while it was stable in acidic conditions. Theanaphthoquinone was identified as an autoxidation product of theaflavin during its stability study in alkaline conditions.
- Jhoo, Jin-Woo,Lo, Chih-Yu,Li, Shiming,Sang, Shengmin,Ang, Catharina Y. W.,Heinze, Thomas M.,Ho, Chi-Tang
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p. 6146 - 6150
(2007/10/03)
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- Enzymatic synthesis of tea theaflavin derivatives and their anti-inflammatory and cytotoxic activities
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Derivatives based on a benzotropolone skeleton (9-26) have been prepared by the enzymatic coupling (horseradish peroxidase/H2O2) of selected pairs of compounds (1-8), one with a vic-trihydroxyphenyl moiety, and the other with an ortho-dihydroxyphenyl structure. Some of these compounds have been found to inhibit TPA-induced mice ear edema, nitric oxide (NO) synthesis, and arachidonic acid release by LPS-stimulated RAW 264.7 cells. Their cytotoxic activites against KYSE 150 and 510 human esophageal squamous cell carcinoma and HT 29 human colon cancer cells were also evaluated.
- Sang, Shengmin,Lambert, Joshua D.,Tian, Shiying,Hong, Jungil,Hou, Zhe,Ryu, Jae-He,Stark, Ruth E.,Rosen, Robert T.,Huang, Mou-Tuan,Yang, Chung S.,Ho, Chi-Tang
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p. 459 - 467
(2007/10/03)
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- Synthesis of theaflavin from epicatechin and epigallocatechin by plant homogenates and role of epicatechin quinone in the synthesis and degradation of theaflavin
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Oxidation products of (-)-epicatechin and (-)-epigallocatechin by treatment with homogenates of 62 plants belonging to 49 families were compared. Forty-six plants were capable of synthesizing theaflavin, a black tea pigment, regardless of whether they contained catechins. Loquat, Japanese pear, and blueberry had activities higher than that of fresh tea leaves after 5 h of treatment; furthermore, these plants oxidized theaflavin to theanaphthoquinone. An additional new metabolite, dehydrotheasinensin, was generated on treatment with fresh tea leaves, eggplant, and unripened Japanese orange. Evidence for the oxidation of epigallocatechin and theaflavin by electron transfer to epicatechin quinone was demonstrated in a time course study using bananas and trapping the quinone intermediates as glutathione conjugates.
- Tanaka, Takashi,Mine, Chie,Inoue, Kyoko,Matsuda, Miyuki,Kouno, Isao
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p. 2142 - 2148
(2007/10/03)
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- Theanaphthoquinone, a novel pigment oxidatively derived from theaflavin during tea-fermentation
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Treatment of a mixture of epicatechin and epigallocatechin with extracts of fresh tea leaf or banana fruit generated a new pigment named theanaphthoquinone, which has a 1,2-naphthoquinone moiety oxidatively derived from the benzotropolone unit of theaflavin.
- Tanaka, Takashi,Betsumiya, Yayoi,Mine, Chie,Kouno, Isao
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p. 1365 - 1366
(2007/10/03)
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