Polymer-Like Polyphenols of Black Tea and Their Lipase and Amylase Inhibitory Activities

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Lipase and amylase inhibitory activities of black tea were examined. After solvent partitioning of a black tea extract with the ethyl acetate and n-butanol, the two soluble fractions showed comparable inhibitory activities. Activity in the ethyl acetate fraction was mainly attributable to polyphenols with low-molecular weights, such as theaflavin gallates. On the other hand, the active substance in the n-butanol layer was ascertained to be a polymer-like substance. 1H- and 13C-NMR spectra showed signals arising from the flavan A-ring and galloyl groups, although signals due to flavan B-rings were not detected, suggesting that the polymer-like substances were generated by oxidative condensation of flavan B-rings, a result which was previously deduced from our results of in vitro catechin oxidation experiments. Enzymatic oxidation of epicatechin 3-O-gallate produced a similar polymer-like substance and suggested that condensation between a B-ring and galloyl groups was involved in the polymerization reaction.

Lipase and amylase inhibitory activities of black tea were examined. After solvent partitioning of a black tea extract with the ethyl acetate and <i>n</i>-butanol, the two soluble fractions showed comparable inhibitory activities. Activity in the ethyl acetate fraction was mainly attributable to polyphenols with low-molecular weights, such as theaflavin gallates. On the other hand, the active substance in the <i>n</i>-butanol layer was ascertained to be a polymer-like substance. <sup>1</sup>H- and <sup>13</sup>C-NMR spectra showed signals arising from the flavan A-ring and galloyl groups, although signals due to flavan B-rings were not detected, suggesting that the polymer-like substances were generated by oxidative condensation of flavan B-rings, a result which was previously deduced from our results of <i>in vitro</i> catechin oxidation experiments. Enzymatic oxidation of epicatechin 3-<i>O</i>-gallate produced a similar polymer-like substance and suggested that condensation between a B-ring and galloyl groups was involved in the polymerization reaction.

収録刊行物

  • Chemical & pharmaceutical bulletin

    Chemical & pharmaceutical bulletin 56(3), 266-272, 2008-03-01

    公益社団法人日本薬学会

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各種コード

  • NII論文ID(NAID)
    110006622627
  • NII書誌ID(NCID)
    AA00602100
  • 本文言語コード
    ENG
  • 資料種別
    ART
  • ISSN
    00092363
  • NDL 記事登録ID
    9394378
  • NDL 雑誌分類
    ZS51(科学技術--薬学) // ZP1(科学技術--化学・化学工業)
  • NDL 請求記号
    Z53-D167
  • データ提供元
    CJP書誌  CJP引用  NDL  NII-ELS  IR  J-STAGE 
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