title: Isolation and structural elucidation of some procyanidins from apple by low-temperature nuclear magnetic resonance.
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 4beta-->8 or 4beta-->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-(4beta-->8)-epicatechin-(4beta-->8)-catechin (6); epicatechin-(4beta-->6)-epicatechin-(4beta-->8)-catechin (7); epicatechin-(4beta-->6)-epicatechin-(4beta-->8)-epicatechin (8); epicatechin-(4beta-->8)-epicatechin-(4beta-->6)-catechin (9); epicatechin-(4beta-->8)-epicatechin-(4beta-->6)-epicatechin (10); and epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-epicatechin (11)]. Compounds 6-11 were detected for the first time as apple constituents.
authors.affiliation: Fundamental Research Laboratory, Asahi Breweries, Ltd., 1-21 Midori 1-chome, Moriya, Ibaraki 302-0106, Japan. toshihiko.shoji@asahibeer.co.jp
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Shoji
authors.forename: Motoh
authors.initials: M
authors.lastname: Mutsuga
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Nakamura
authors.forename: Tomomasa
authors.initials: T
authors.lastname: Kanda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akiyama
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Goda
mesh_terms: D044946:Biflavonoids; D002392:Catechin / Q000737:chemistry* / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D005638:Fruit / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D027845:Malus / Q000737:chemistry*; D044945:Proanthocyanidins; D021241:Spectrometry, Mass, Electrospray Ionization; D013696:Temperature
chemical_list: D044946:Biflavonoids; D044945:Proanthocyanidins; C479579:procyanidin B1; C479580:procyanidin B2; C017674:procyanidin; D002392:Catechin