title: Polyphenols from peanut skins and their free radical-scavenging effects.
abstract: Separation of the water-soluble fraction of peanut skins led to the isolation of five proanthocyanidins. Based on the spectroscopic investigation and partial acid catalyzed degradation, their structures were determined to be epicatechin-(2beta-->O -->7, 4beta -->6)-[epicatechin-(4beta-->8)]-catechin (1), epicatechin-(2beta-->O -->7, 4beta-->8) epicatechin-(4beta-->8)-catechin-(4alpha-->8)-epicatechin (2), and procyanidins B2 (3), B3 (4) and B4 (5). The absolute configuration of the new compounds was determined from their circular dichroism curves and the (1)H NMR spectra of analysis of flavan-3-ols formed by thiolytic degradation of 1 and 2 in the presence of a chiral dirhodium complex (dirhodium tetra-(R)-(trifluoromethyl) phenyl acetate).
authors.affiliation: School of Pharmaceutical Sciences, Shandong University, Jinan 250012, PR China. louhongxiang@sdu.edu.cn
authors.forename: Hongxiang
authors.initials: H
authors.lastname: Lou
authors.forename: Huiqing
authors.initials: H
authors.lastname: Yuan
authors.forename: Bin
authors.initials: B
authors.lastname: Ma
authors.forename: Dongmei
authors.initials: D
authors.lastname: Ren
authors.forename: Mei
authors.initials: M
authors.lastname: Ji
authors.forename: Syuichi
authors.initials: S
authors.lastname: Oka
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D010367:Arachis / Q000737:chemistry*; D044946:Biflavonoids / Q000737:chemistry; D002392:Catechin / Q000737:chemistry; D002942:Circular Dichroism; D005419:Flavonoids / Q000032:analysis / Q000302:isolation & purification*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D010636:Phenols / Q000302:isolation & purification*; D059808:Polyphenols; D044945:Proanthocyanidins / Q000737:chemistry / Q000302:isolation & purification; D012238:Rhodium / Q000737:chemistry; D013439:Sulfhydryl Reagents / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D044946:Biflavonoids; D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D059808:Polyphenols; D044945:Proanthocyanidins; D013439:Sulfhydryl Reagents; C404987:flavan-3-ol; C017674:procyanidin; D002392:Catechin; D012238:Rhodium