Antioxidant properties of prunes (Prunus domestica L.) and their constituents.
Prunes contain large amounts of phenolics and show high antioxidant activity. The aim of this study is to clarify the contents of caffeoylquinic acid (CQA) isomers, and to estimate the contribution of these isomers to the antioxidant activity of prunes. Furthermore, structural elucidation and evaluation of antioxidant activity of prune components were also performed. CQA isomers in prunes were quantified by HPLC analysis, and it has become apparent that prunes contain relatively high amount of 4-O-caffeoylquinic acid. The contribution of CQA isomers to the antioxidant activity of prunes was revealed to be 28.4% on the basis of oxygen radical absorbance capacity (ORAC); hence, it was indicated that residual ORAC is dependent on unknown antioxidant components. Total 28 compounds were isolated and their structures were elucidated by NMR and MS analyses. Four abscisic acid related compounds, a chromanon, and a bipyrrole were novel. Each CQA isomer in prunes showed high antioxidant activities when measured by the oil stability index (OSI) method, O2- scavenging activity, and ORAC. Other isolated compounds such as hydroxycinnamic acids, benzoic acids, coumarins, lignans, and flavonoid showed high ORAC values. Furthermore, a novel chromanon indicated a remarkable synergistic effect on ORAC of CQA isomers.
Kayano
Shin-ichi
S
Research and Development Institute, MIKI Corporation, 12-4, Naruohama 3, Nishinomiya 663-8142, Japan.
Kikuzaki
Hiroe
H
Yamada
Naoko Fukutsuka
NF
Aoki
Asuka
A
Kasamatsu
Kumi
K
Yamasaki
Yuka
Y
Ikami
Takao
T
Suzuki
Tomoo
T
Mitani
Takahiko
T
Nakatani
Nobuji
N
D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D005511:Food Handling; D005609:Free Radicals; D007536:Isomerism; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification; D027861:Prunus / Q000737:chemistry*; D011801:Quinic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D013329:Structure-Activity Relationship
D000975:Antioxidants; D005609:Free Radicals; D010636:Phenols; C472707:caffeoylquinic acid; D011801:Quinic Acid