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


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Title: Polymer-Like Polyphenols of Black Tea and Their Lipase and Amylase Inhibitory Activities
Authors: Kusano, Rie / Andou, Hisashi / Fujieda, Miho / Tanaka, Takashi / Matsuo, Yosuke / Kouno, Isao
Issue Date: 1-Mar-2008
Publisher: The Pharmaceutical Society of Japan
Citation: Chemical & Pharmaceutical Bulletin v.56(3) p.266-272, 2008
Abstract: 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.
Keywords: black tea / lipase / amylase / polyphenol / oxidation / thearubigin
URI: http://hdl.handle.net/10069/17916
ISSN: 00092363
DOI: 10.1248/cpb.56.266
Rights: (c) 2008 The Pharmaceutical Society of Japan
Type: Journal Article
Text Version: publisher
Appears in Collections:Articles in academic journal

Citable URI : http://hdl.handle.net/10069/17916

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