Isolation and Structural Elucidation of Some Procyanidins from Apple by Low-Temperature Nuclear Magnetic Resonance

Toshihiko Shoji,*† Motoh Mutsuga,§ Takatoshi Nakamura,§ Tomomasa Kanda,† Hiroshi Akiyama,§ and Yukihiro Goda§
Fundamental Research Laboratory, Asahi Breweries, Ltd., 1-21 Midori 1-chome, Moriya, Ibaraki 302-0106, Japan, and Division of Foods, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
J. Agric. Food Chem., 2003, 51 (13), pp 3806–3813
DOI: 10.1021/jf0300184
Publication Date (Web): May 24, 2003
Copyright © 2003 American Chemical Society
*

 Author to whom correspondence should be addressed (fax +81-297-46 1506; e-mail toshihiko.shoji@asahibeer.co.jp).

,
†

 Asahi Breweries, Ltd.

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§

 National Institute of Health Sciences.

Abstract

Procyanidin fractions from apple were separated according to the degree of polymerization using normal phase chromatography. Evaluation of physiological functionalities of procyanidins requires individual structural determination. However, it is difficult to elucidate the structure of procyanidins, in particular those with (+)-epicatechin (1) or (−)-catechin (2) units, and determine whether the interflavanoid bonds are 4β→8 or 4β→6 without cleavage and acetylation. Structural determination used LC-MS and low-temperature NMR. Nine procyanidins were separated by preparative HPLC consisting of three well-known procyanidins [procyanidin B1 (3), procyanidin B2 (4), and procyanidin C1 (5)] and six new procyanidins [epicatechin-(4β→8)-epicatechin-(4β→8)-catechin (6); epicatechin-(4β→6)-epicatechin-(4β→8)-catechin (7); epicatechin-(4β→6)-epicatechin-(4β→8)-epicatechin (8); epicatechin-(4β→8)-epicatechin-(4β→6)-catechin (9); epicatechin-(4β→8)-epicatechin-(4β→6)-epicatechin (10); and epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin (11)]. Compounds 6−11 were detected for the first time as apple constituents.

Keywords: NMR; apple; procyanidins; tetramer; trimer

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History

  • Published In Issue June 18, 2003
  • Received for review January 9, 2003. Revised manuscript received March 26, 2003. Accepted March 28, 2003. Part of this work was financially supported by a grant from the Human Science, Japan.

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