title: Preparation and characterisation of peanut seed skin polyphenols.
abstract: Using α-amylase inhibition as a separation guide, polyphenolic compounds from peanut seed skin were prepared. During preparation, specific α-amylase inhibitory activities were increased about 4-fold. High-resolution MALDI-TOF mass spectra showed that the structure of this sample was a series of polyflavan-3-ols, up to 15-mer, composed of catechin/epicatechin units together with several afzelechin/epiafzelechin units and gallocatechin/epigallocatechin units. The observed precious mass values suggest that the polymers consist of both interflavanoid C-C linkages (A-type) and interflavanoid ether linkages (B-type). Oral administration of the polyphenol fraction to rats fed corn starch significantly suppressed an increase in blood glucose levels in a dose dependent manner. Administration of the polyphenol fraction to rats fed maltose or sucrose delayed the increase in blood glucose levels. These results suggest peanut seed skin contains polyphenols with strong α-amylase inhibitory activity, which retard absorption of carbohydrates and mainly function through inhibition of α-amylase.
authors.affiliation: Bioscience, Integrated Center for Sciences, Ehime University, Shitsukawa, Toon, Ehime, Japan. Electronic address: tsujita@m.ehime-u.ac.jp.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tsujita
authors.affiliation: Ehime Institute of Industrial Technology, 2-5-48 Higashimura-minami, Imabari, Ehime, Japan.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Shintani
authors.affiliation: Research Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sato
mesh_terms: D000818:Animals; D010367:Arachis / Q000737:chemistry*; D008297:Male; D010936:Plant Extracts / Q000737:chemistry; D059808:Polyphenols / Q000737:chemistry*; D051381:Rats; D012639:Seeds / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D059808:Polyphenols
keywords: Amylase inhibitor; Oral carbohydrate tolerance test; Peanut seed skin; Polyphenol