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Vasorelaxant effect of stilbenes from rhizome extract of rhubarb ( Rheum undulatum ) on the contractility of rat aorta
Author(s) -
Yoo Mi Young,
Oh KwangSeok,
Lee Jung Won,
Seo Ho Won,
Yon Gyu Hwan,
Kwon Dae Young,
Kim Young Sup,
Ryu Shi Yong,
Lee Byung Ho
Publication year - 2007
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.2042
Subject(s) - piceatannol , phenylephrine , rhizome , chemistry , pharmacology , nitric oxide , resveratrol , traditional medicine , pharmacognosy , medicine , biological activity , biochemistry , in vitro , organic chemistry , blood pressure
The vascular relaxant effect of the rhizome extract of Rheum undulatum was evaluated with isolated rat thoracic aorta preparations. The methanol extract of the rhizome induced a concentration‐dependent relaxation of aortic preparations precontracted with 0.3 µ m phenylephrine (EC 50 value: 5.8 µg/mL). The activity‐guided fractionation of the extract led to the isolation of seven hydroxystilbene components as active principles, i.e. piceatannol, resveratrol, desoxyrhapontigenin, rhapontigenin, piceid, rhaponticin and ε ‐viniferin. Of these, piceatannol, a tetrahydroxystilbene, exhibited the most potent vascular relaxant effect in rat aortic preparations (EC 50 value 2.4 µ m ). The vasorelaxant effect of piceatannol on endothelium‐intact aorta rings was diminished completely by the removal of functional endothelium or by pretreatment of the aortic tissues with N G ‐nitro‐ l ‐arginine methyl ester. These results suggest that piceatannol may be the major mediator responsible for the vasorelaxing properties of the rhizome extract of Rheum undulatum and the vasorelaxant effects of the piceatannol may be mediated via endothelium‐dependent nitric oxide signaling pathway. Copyright © 2006 John Wiley & Sons, Ltd.