Antioxidant phenolic constituents in roots of Rheum officinale and Rubia cordifolia: Structure-radical scavenginq activity relationships

TY - JOUR

T1 - Antioxidant phenolic constituents in roots of Rheum officinale and Rubia cordifolia

T2 - Structure-radical scavenginq activity relationships

AU - Cai, Yizhong

AU - Sun, Mei

AU - Xing, Jie

AU - Corke, Harold

PY - 2004/12/29

Y1 - 2004/12/29

N2 - The phenolic constituents in the roots of Rheum officinale and Rubia cordifolia were identified with the aid of high-performance liquid chromatography and liquid chromatography-mass spectrometry and by comparison with authentic standards. A total of 17 hydroxyanthraquinones, gallic acid, and tannins were separated, and 14 of them were identified, being the main phenolic constituents present. Their antioxidant activity (Trolox equivalent antioxidant capacity) was evaluated using the improved 2,2-azino-bis(3-ethylbenzothiazoline- 6-sulfonic acid)diammonium salt method. Hydroxyanthraquinones were the predominant antioxidant phenolic constituents in the roots of R. cordifolia, and tannins and gallic acid were the predominant antioxidant phenolic constituents in the roots of R. officinale. The structure-radical scavenging activity relationships of the tested hydroxyanthraquinones were systematically demonstrated as follows: Hydroxy groups on one benzene ring of the anthraquinone structure were essential for hydroxyanthraquinones to show activity, the ortho-dihydroxy structure in the hydroxyanthraquinone molecules could greatly enhance their radical scavenging effect, and glycosylation of the hydroxyanthraquinones reduced activity.

AB - The phenolic constituents in the roots of Rheum officinale and Rubia cordifolia were identified with the aid of high-performance liquid chromatography and liquid chromatography-mass spectrometry and by comparison with authentic standards. A total of 17 hydroxyanthraquinones, gallic acid, and tannins were separated, and 14 of them were identified, being the main phenolic constituents present. Their antioxidant activity (Trolox equivalent antioxidant capacity) was evaluated using the improved 2,2-azino-bis(3-ethylbenzothiazoline- 6-sulfonic acid)diammonium salt method. Hydroxyanthraquinones were the predominant antioxidant phenolic constituents in the roots of R. cordifolia, and tannins and gallic acid were the predominant antioxidant phenolic constituents in the roots of R. officinale. The structure-radical scavenging activity relationships of the tested hydroxyanthraquinones were systematically demonstrated as follows: Hydroxy groups on one benzene ring of the anthraquinone structure were essential for hydroxyanthraquinones to show activity, the ortho-dihydroxy structure in the hydroxyanthraquinone molecules could greatly enhance their radical scavenging effect, and glycosylation of the hydroxyanthraquinones reduced activity.

KW - Anthraquinones

KW - Antioxidant activity

KW - Hydroxyanthraquinones

KW - Phenolic constituents

KW - Radical scavenging activity

KW - Rheum officinale

KW - Rubia cordifolia

KW - Structure-activity relationships

UR - http://www.scopus.com/inward/record.url?scp=11144241260&partnerID=8YFLogxK

U2 - 10.1021/jf0489116

DO - 10.1021/jf0489116

M3 - 文章

C2 - 15612771

AN - SCOPUS:11144241260

VL - 52

SP - 7884

EP - 7890

JO - Journal of Agricultural and Food Chemistry

JF - Journal of Agricultural and Food Chemistry

SN - 0021-8561

IS - 26

ER -