Antihypertensive, vasorelaxant and inotropic effects of an ethanolic extract of the roots of Saururus chinensis.
OBJECTIVE
The present study was performed to evaluate the cardiovascular effects of ethanolic extract of the roots of Saururus chinensis (EERSC) in rats.


METHODS
The effects of EERSC on the vascular responses of isolated rat aorta, the cardiac functions in isolated rat heart, and the antihypertensive effects in spontaneously hypertensive rats (SHRs) were evaluated.


RESULTS
In isolated rat aortic preparations, EERSC exhibited a potent vasorelaxant effect with EC(50) value of 9.1 microg/ml. This relaxation was significantly inhibited by denudation of endothelial layer or by pretreatment with N(G)-nitro-l-arginine methyl ester. In addition, the raising extracellular K(+) (45 mM), or pretreatment with tetraethylammonium (10 mM) significantly inhibited EERSC-induced vasorelaxation in endothelium-denuded aortic rings. In isolated rat hearts, EERSC significantly reduced cardiac functions such as left ventricle pressure and heart rate. In an antihypertensive study with SHRs, long-term oral administrations of EERSC decreased blood pressure of SHRs (approximately 20 mmHg).


CONCLUSIONS
These results suggest that chronic treatment with EERSC exerts an antihypertensive effect in SHRs, and its direct vasorelaxant properties and negative inotropic actions may contribute to reduce the elevated blood pressure.
Ryu
Shi Yong
SY
Drug Discovery Division, Korea Research Institute of Chemical Technology, 100 Jangdong, Yuseong, Daejeon 305-343, Republic of Korea.
Oh
Kwang-Seok
KS
Kim
Young Sup
YS
Lee
Byung Ho
BH
D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D051381:Rats; D011918:Rats, Inbred SHR; D017207:Rats, Sprague-Dawley; D032134:Saururaceae / Q000737:chemistry*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology
D000959:Antihypertensive Agents; D002316:Cardiotonic Agents; D010936:Plant Extracts; D014665:Vasodilator Agents