28543-07-9Relevant articles and documents
Specificity of tyrosinase-catalyzed synthesis of theaflavins
Narai-Kanayama, Asako,Kawashima, Aya,Uchida, Yuuka,Kawamura, Miho,Nakayama, Tsutomu
, p. S452 - S458 (2016)
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.
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
Takemoto, Masumi,Takemoto, Hiroaki,Sakurada, Asuka
, p. 5038 - 5040 (2014)
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.
Benzotropolone derivatives and modulation of inflammatory response
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Page/Page column 9, (2008/06/13)
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.
Enzymatic synthesis of tea theaflavin derivatives and their anti-inflammatory and cytotoxic activities
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
, p. 459 - 467 (2007/10/03)
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.