お茶ガラに存在する抗酸化活性について  [in Japanese] Identification and Antioxidant Activity of Several Pigments from the Residual Green Tea(Camellia sinensis) after Hot Water Extraction  [in Japanese]

Abstract

緑茶は古くより様々な薬理効果が知られ, 特に緑茶中のカテキン類の抗酸化活性の重要性が多くの研究によって示されている.これに対して著者らは, カテキン類を熱湯抽出した後の茶ガラ中に存在する抗酸化活性を分析した.茶ガラをアセトン処理し, その抽出液をリノール酸から過酸化脂質が生成される実験系に添加したところ, 強い抑制作用が観察された.そこで, アセトン抽出液をシリカゲル薄層クロマトグラフィーを用いて分析したところ, 複数の色素の存在が明らかとなり, その色調, Rf値, および分光スペクトラムの特徴によりそれらはクロロフィル類(aとb), フェオフィチン類(aとb)そしてカロチノイド類(β-カロチンとルテイン)と考えられた.そこでそれぞれの色素について過酸化脂質の生成に対する抑制効果を調べたところ, すべての色素が有意の抗酸化活性を示した.以上の結果は, 緑茶の有する抗酸化作用の観点からカテキン類を含む「飲むお茶」とともに他の多くの抗酸化物質を含む「食べるお茶」の摂取が生活習慣病を予防するのに有効である可能性が示唆された。

Antioxidant activity of green tea extract or tea-derived polyphenols has been extensively studied. However, antioxidant activity in the non-polyphenolic fraction of green tea has been poorly analyzed. In the present study, we analyzed the antioxidant activity of the non-polyphenolic fraction of the residual green tea (Camellia sinensis) after hot water extraction using the aluminum chloride method. The non-polyphenolic fraction of residual green tea caused a significant suppression against hydroperoxide generation from oxidized linoleic acid in a dose-dependent manner. When the concentrate of the non-polyphenolic fraction was applied to a silica gel TLC plate and developed, six color spots were observed, which were considered to be chlorophylls a and b, pheophytins a and b, carotenoids, such as β-carotene and lutein according to their specific colors, Rf values of silica gel TLC and spectrophotometric properties. Among these pigments, pheophytins a and b showed relatively abundant amounts, and the second major group of the pigment was chlorophylls a and b, and carotenoids such as β-carotene and lutein indicated lower concentrations. Although all these pigments exhibited significant antioxidant activities, the ranks of suppressive activity against hydroperoxide generation were chlorophyll a>lutein>pheophytin a>chlorophyll b>β-carotene>pheophytin b. These results suggest that the non-polyphenolic fraction of residual green tea has a potent suppressive activity against hydroperoxide generation from oxidized linoleic acid, which is derived from the antioxidant activities of chlorophylls a and b, pheophytins a and b, β-carotene and lutein. This finding also implys that the combined intake of polyphenols in water-soluble fraction and antioxidative pigments in the non-polyphenolic fraction of green tea will be more efficient to prevent life style-related chronic diseases.

Journal

Journal of UOEH   [List of Volumes]

Journal of UOEH 23(4), 335-344, 2001-12-01  [Table of Contents]

The UOEH Association of Health Sciences

Cited by:  3

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Codes

  • NII Article ID (NAID) :
    110001260153
  • NII NACSIS-CAT ID (NCID) :
    AN0009832X
  • Text Lang :
    JPN
  • Article Type :
    Journal Article
  • ISSN :
    0387821X
  • NDL Article ID :
    6003979
  • NDL Source Classification :
    ZS7(科学技術--医学)
  • NDL Call No. :
    Z19-1000
  • Databases :
    CJPref  NDL  NII-ELS 

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