Antioxidant constituents from rhubarb: Structural requirements of stilbenes for the activity and structures of two new anthraquinone glucosides

Citation
H. Matsuda et al., Antioxidant constituents from rhubarb: Structural requirements of stilbenes for the activity and structures of two new anthraquinone glucosides, BIO MED CH, 9(1), 2001, pp. 41-50
Citations number
33
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry & Analysis
Journal title
BIOORGANIC & MEDICINAL CHEMISTRY
ISSN journal
0968-0896 → ACNP
Volume
9
Issue
1
Year of publication
2001
Pages
41 - 50
Database
ISI
SICI code
0968-0896(200101)9:1<41:ACFRSR>2.0.ZU;2-V
Abstract
The methanolic extracts from five kinds of rhubarb were found to show scave nging activity for DPPH radical and .O-2(-). Two new anthraquinone glucosid es were isolated from the rhizome of Rheum undulatum L. together with two a nthraquinone glucosides, a naphthalene glucoside, and 10 stilbenes. In the screening test for radical scavenging activity of rhubarb constituents, sti lbenes and a naphthalene glucoside showed activity, but anthraquinones and sennosides did not. In addition, most stilbenes inhibited lipid peroxidatio n of erythrocyte membrane by tert-butyl hydroperoxide. Detailed examination of the scavenging effect on various related compounds suggested the follow ing structural requirements; 1) phenolic hydroxyl groups are essential to s how the activity; 2) galloyl moiety enhances the activity; 3) glucoside moi ety reduces the activity; 4) dihydrostilbene derivatives maintain the scave nging activity for the DPPH radical, but they show weak activity for .O-2(- ) In addition, several stilbenes with both the 3-hydroxyl and 4'-methoxyl g roups inhibited xanthine oxidase. (C) 2000 Elsevier Science Ltd. All rights reserved.