EGCg quinone dimer A | 225793-49-7

• 分子结构分类: 有机化合物 - 苯丙烷和聚酮 - 黄酮类化合物
• 英文名称: EGCg quinone dimer A
• 英文别名: 1,1a(2)-[2,2a(2)-(2,3,3a,4,7,7a-Hexahydro-2,3a,7a,8-tetrahydroxy-4,9-dioxo-3,2,7-[1]buten[1]yl[4]ylidenebenzofuran-6,11-diyl)bis[(2R,3R)-3,4-dihydro-5,7-dihydroxy-2H-1-benzopyran-2,3-diyl]] bis(3,4,5-trihydroxybenzoate)；[(2R,3R)-2-[11-[(2R,3R)-5,7-dihydroxy-3-(3,4,5-trihydroxybenzoyl)oxy-3,4-dihydro-2H-chromen-2-yl]-1,6,7,9-tetrahydroxy-5,13-dioxo-8-oxatetracyclo[7.4.0.02,7.06,10]trideca-3,11-dien-3-yl]-5,7-dihydroxy-3,4-dihydro-2H-chromen-3-yl] 3,4,5-trihydroxybenzoate
• CAS: 225793-49-7
• 化学式: C₄₄H₃₄O₂₃
• 分子量: 930.74
• InChiKey: QJNSSFKWJUQTHD-OSHLZBPJSA-N

物化性质

• 密度：
  2.11±0.1 g/cm3(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  -1.2
• 重原子数：
  67
• 可旋转键数：
  8
• 环数：
  10.0
• sp3杂化的碳原子比例：
  0.27
• 拓扑面积：
  398
• 氢给体数：
  14
• 氢受体数：
  23

反应信息

• 作为反应物：
  描述：

  EGCg quinone dimer A 在 phosphate buffer 、 溶剂黄146 作用下， 以 乙醇 为溶剂， 反应 3.5h， 生成 theasinensin A
  参考文献：
  名称：

  Production of theasinensins A and D, epigallocatechin gallate dimers of black tea, by oxidation–reduction dismutation of dehydrotheasinensin A

  摘要：

  Theasinensins A and D are B,B'-linked dimers of (-)-epigallocatechin 3-O-gallate connected through R and S biphenyl bonds, respectively, and are major constituents of black tea. Enzymatic oxidation of epigallocatechin 3-O-gallate produced dehydrotheasinensin A, and the structure was shown to be equivalent to an o-quinone of theasinensin A. When the aqueous solution of dehydrotheasinensin A was heated, theasinensin D was produced along with galloyl oolongtheanin. On the other hand, dehydrotheasinensin A was converted to theasinensins A and D along with oxidation products in phosphate buffer at pH 6.8 at room temperature. The results strongly suggested that theasinensins in black tea were produced by oxidation-reduction dismutation of dehydrotheasinensin. (C) 2003 Elsevier Ltd. All rights reserved.

  DOI：

  10.1016/j.tet.2003.08.025
• 作为产物：
  描述：

  (-)-表没食子儿茶素没食子酸酯 以 水 为溶剂， 反应 1.0h， 生成 没食子酸 、 theacitrinin A 、 EGCg quinone dimer A
  参考文献：
  名称：

  (–)-表没食子儿茶素没食子酸酯的等离子体诱导氧化产物具有消化酶抑制作用

  摘要：

  (−)-表没食子儿茶素没食子酸酯 (EGCG) 是绿茶 ( Camellia sinensis ) 中的主要膳食成分，在氧化条件下相对不稳定。本研究评估了使用非热介质阻挡放电 (DBD) 等离子体来提高 EGCG 氧化产物的抗消化酶能力。将纯 EGCG 溶解在水溶液中，并用 DBD 等离子体照射 20、40 和 60 分钟。与母体 EGCG 相比，照射 60 分钟的反应物对 α-葡萄糖苷酶和 α-淀粉酶表现出改善的抑制特性。使用光谱方法对经等离子体照射 60 分钟的 EGCG 中的这些氧化产物1 – 3的化学结构进行了表征。在氧化产物中，EGCG醌二聚体A( 1 )对α-葡萄糖苷酶和α-淀粉酶表现出最有效的抑制作用，IC 50值分别为15.9±0.3和18.7±0.3μM。这些值显着高于阳性对照阿卡波糖的值。根据定量高效液相色谱分析，最活跃的化合物1在等离子体照射60分钟的反应物中含量最丰富。这些结果表明，EGCG

  DOI：

  10.3390/molecules26195799

文献信息

• Antioxidant Chemistry of Green Tea Catechins. New Oxidation Products of (−)-Epigallocatechin Gallate and (−)-Epigallocatechin from Their Reactions with Peroxyl Radicals
  作者：Susanne Valcic、Jeanne A. Burr、Barbara N. Timmermann、Daniel C. Liebler

  DOI：10.1021/tx000080k

  日期：2000.9.1

  antioxidant reactions in EGCG and EGC is the trihydroxyphenyl B-ring, regardless of the presence of a 3-galloyl moiety. A stoichiometric factor n of 4.16 +/- 0.51 was measured for EGCG, whereas factors of 2.20 +/- 0.26 was found for EGC and 2.33 +/- 0.18 measured for methyl gallate. These values represent the net peroxyl radical trapping per catechin molecule by several competing reactions. EGCG and

  绿茶儿茶素（-）-表没食子儿茶素没食子酸酯（EGCG）和（-）-表没食子儿茶素（EGC）与偶氮引发剂2,2'-偶氮二（2，4-二甲基戊腈）（AMVN）热分解为过氧自由基反应生产几种氧化产物。这些产品的结构阐明可以为抗氧化剂反应的特定机理提供见解。我们分离并鉴定了先前未报告的EGCG反应产物和EGC的三种反应产物。在EGCG产物中，B环被转化为开环的不饱和二羧酸部分。EGC产物包括七元B环酸酐和对称的EGC二聚体，它们都是先前描述的EGCG氧化产物的类似物。EGC的第三个产物是不对称的二聚体。在所有确定的产品中，变化仅发生在EGCG或EGC的B环上。这证实了我们先前的观察结果，无论是否存在3- galloyl部分，EGCG和EGC中抗氧化剂反应的主要部位是三羟基苯基B环。EGCG的化学计量系数n为4.16 +/- 0.51，EGC的化学计量系数n为2.20 +/- 0.26，没食子酸甲酯的化学计量系数n为2
• Structures of two new oxidation products of green tea polyphenols generated by model tea fermentation
  作者：Takashi Tanaka、Chie Mine、Isao Kouno

  DOI：10.1016/s0040-4020(02)01061-x

  日期：2002.10

  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

  为了阐明绿茶儿茶素在茶发酵过程中的氧化机理，纯净的儿茶素被无叶茶素的匀浆茶叶氧化。（-）-表儿茶素和（-）-表没食子儿茶素混合物的氧化产生了一种新的代谢产物，称为脱氢茶黄素，它是由红茶色素茶黄素的苯并二氢马酚酮部分氧化而成的。（-）-表儿茶素和（-）-表没食子儿素3- O-没食子酸酯的混合物的类似氧化产生了新的（-）-表没食子儿茶素3- O-没食子酸酯的二聚体，其是通过两个邻苯三酚环的氧化和环加成产生的。 。通过分光光度法确定结构，并提出了形成产物的氧化机理。
• Production and degradation mechanism of theacitrin C, a black tea pigment derived from epigallocatechin-3-O-gallate via a bicyclo[3.2.1]octane-type intermediate
  作者：Yosuke Matsuo、Yan Li、Sayaka Watarumi、Takashi Tanaka、Isao Kouno

  DOI：10.1016/j.tet.2011.01.058

  日期：2011.3

  Black tea is rich in polyphenols and has been shown to have various health benefits: however, its components have not yet been clarified in detail. Enzymatic oxidation of epigallocatechin-3-O-gallate, the most abundant polyphenol in tea, is thought to contribute significantly to the production of black tea polyphenols. We identified theacitrin C, an unstable black tea pigment, as an enzymatic oxidation product of epigallocatechin-3-O-gallate. Degradation of theacitrin C afforded theacitrinin A and 2,3,5,7-tetrahydroxychroman-3-O-gallate. Furthermore, theacitrinin B, which was isolated from black tea, is deduced to be a degradation product of theacitrin A, the desgalloyl analogue of theacitrin C. The structures of theacitrinins A and B were elucidated based on spectroscopic data. This is the first time that a degradation product of theacitrin has been isolated from black tea. We also examined the influence of esterification of the epigallocatechin C-3 hydroxyl group on the decomposition of bicyclo[3.2.1]octane-type intermediates. (C) 2011 Elsevier Ltd. All rights reserved.
• A Novel Black Tea Pigment and Two New Oxidation Products of Epigallocatechin-3-<i>O</i>-gallate
  作者：Takashi Tanaka、Yosuke Matsuo、Isao Kouno

  DOI：10.1021/jf0512656

  日期：2005.9.1

  During tea fermentation, oxidation-reduction dismutation of a number of quinone metabolites of tea catechins yields numerous minor products, which make it difficult to separate and purify black tea polyphenols. In this study, epigallocatechin-3-O-gallate was enzymatically oxidized and then the unstable quinone metabolites in the oxidation mixture were hydrogenated with 2-mercaptoethanol to reduce production of inseparable minor dismutation products. As a result, three new oxidation products including a new black tea pigment were isolated, and their structures were determined based on chemical and spectroscopic data. Dehydrotheasinensin AQ is a new reddish-orange pigment with a 1,2-diketone structure, and its presence in commercial black tea was confirmed. In addition, a new quinone dimer with a complex caged structure and a trimer of epigallocatechin-3-O-gallate were also isolated and their production mechanisms are proposed. The presence of this trimer suggested participation of galloyl quinones in production of minor polyphenols in black tea.