title: High molecular weight persimmon (Diospyros kaki L.) proanthocyanidin: a highly galloylated, A-linked tannin with an unusual flavonol terminal unit, myricetin.
abstract: MALDI-TOF MS suggested that the high molecular weight proanthocyanidin (condensed tannin) from persimmon (Diospyros kaki L.) pulp comprised a heteropolyflavanol series with flavan-3-O-galloylated extenders, flavan-3-ol and flavonol terminal units, and A-type interflavan linkages. Thiolysis-HPLC-ESI-MS with DAD, electrochemical, and ESI-MS detection confirmed a previously unreported terminal unit, the flavonol myricetin, in addition to the typical flavan-3-ols catechin and epigallocatechin gallate. The extender units were epicatechin, epigallocatechin, (epi)gallocatechin-3-O-gallate, and (epi)catechin-3-O-gallate. The crude tannin had a high prodelphinidin content (65%) and a high degree of 3-O-galloylation (72%). The material was fractionated on Toyopearl TSK-HW-50-F to yield fractions distinguished by degree of polymerization (DP). Thiolysis suggested that the persimmon tannin was composed of polymers ranging from 7 to 20 kDa (DP 19-47), but sizes estimated by GPC were 50-70% smaller. The crude material was chemically degraded with acid to yield products that were amenable to NMR and ESI-MS analysis, which were used to establish for the first time that persimmon tannin has a mixture of B-type and A-type linkages.
authors: College of Food Science and Technology, Huazhong Agricultural University, Wuhan, China 430070. lichmyl@mail.hzau.edu.cn
authors: Chunmei
authors: C
authors: Li
authors: Rachael
authors: R
authors: Leverence
authors: John D
authors: JD
authors: Trombley
authors: Shufen
authors: S
authors: Xu
authors: Jie
authors: J
authors: Yang
authors: Yan
authors: Y
authors: Tian
authors: Jess D
authors: JD
authors: Reed
authors: Ann E
authors: AE
authors: Hagerman
mesh_terms: D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D029788:Diospyros / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D044948:Flavonols / Q000737:chemistry*; D008970:Molecular Weight; D044945:Proanthocyanidins / Q000737:chemistry / Q000494:pharmacology*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013634:Tannins / Q000737:chemistry*
chemical_list: D005419:Flavonoids; D044948:Flavonols; D044945:Proanthocyanidins; D013634:Tannins; C013221:proanthocyanidin; C040015:myricetin