title: First Report ofEurycoma longifoliaJack Root Extract Causing Relaxation of Aortic Rings in Rats.
abstract: AlthoughEurycoma longifoliahas been studied for erectile function, the blood pressure- (BP-) lowering effect has yet to be verified. Hence, this study aims at investigating the BP-lowering properties of the plant with a view to develop an antihypertensive agent that could also preserve erectile function. Ethanolic root extract was partitioned by hexane, dichloromethane (DCM), ethyl acetate, butanol, and water. The DCM fraction, found to be potent in relaxing phenylephrine- (PE-) precontracted rat aortic rings, was further purified by column chromatography. Subfraction DCM-II, being the most active in relaxing aortae, was studied for effects on the renin-angiotensin and kallikrein-kinin systems in aortic rings. The effect of DCM-II on angiotensin-converting enzyme (ACE) activity was also evaluatedin vitro. Results showed that DCM-II reduced (p< 0.05) the contractions evoked by angiotensin I and angiotensin II (Ang II). In PE-precontracted rings treated with DCM-II, the Ang II-induced contraction was attenuated (p< 0.05) while bradykinin- (BK-) induced relaxation enhanced (p< 0.001).In vitro, DCM-II inhibited (p< 0.001) the activity of ACE. These data demonstrate that the vasodilatory effect of DCM-II appears to be mediatedviainhibition of Ang II type 1 receptor and ACE as well as enhancement of Ang II type 2 receptor activation and BK activity.
authors: Department of Physiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors: Bae Huey
authors: 0000-0003-1223-0746
authors: BH
authors: Tee
authors: Department of Physiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors: See Ziau
authors: 0000-0001-6138-1271
authors: SZ
authors: Hoe
authors: Department of Physiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors: Swee Hung
authors: 0000-0003-4700-1572
authors: SH
authors: Cheah
authors: Department of Physiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors: Sau Kuen
authors: 0000-0002-1880-7289
authors: SK
authors: Lam
mesh_terms: D000803:Angiotensin I / Q000378:metabolism; D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001011:Aorta / Q000187:drug effects* / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D001920:Bradykinin / Q000378:metabolism; D035701:Eurycoma / Q000737:chemistry*; D016234:Kallikrein-Kinin System / Q000187:drug effects; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012084:Renin-Angiotensin System / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D000959:Antihypertensive Agents; D010936:Plant Extracts; D014665:Vasodilator Agents; D000804:Angiotensin II; D000803:Angiotensin I; D001920:Bradykinin