Polyphenols from peanut skins and their free radical-scavenging effects.
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).
Lou
Hongxiang
H
School of Pharmaceutical Sciences, Shandong University, Jinan 250012, PR China. louhongxiang@sdu.edu.cn
Yuan
Huiqing
H
Ma
Bin
B
Ren
Dongmei
D
Ji
Mei
M
Oka
Syuichi
S
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
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