title: Cardiovascular and diuretic activity of kaurene derivatives of Xylopia aethiopica and Alepidea amatymbica.
abstract: The extractives, crude and pure, of Alepidea amatymbica (AA) and Xylopia aethiopica (XA) were subjected to bioassay-directed phytochemical examination for potential cardiovascular and diuretic activity. All extractives and derivatives (XA/O, AA/1, xylopic acid, AA/3, AA/4, AA/5, AA/6, XA/1, XA/2, XA/3) displayed low toxicity, with LC(50) 0.5-5.0 ng/ml. For the first time, diterpene kaurenoids were reported to have significant systemic hypotensive and coronary vasodilatory effect accompanied with bradycardia. These effects were attributed to calcium antagonistic mechanism. The diuretic and natriuretic effects found were similar to the effects of chlorothiazide, suggesting inhibition of Na+ and K+ reabsorption in the early portion of the distal tubule. Further experiments are needed to elaborate the exact mechanisms of the hypotensive and diuretic effects of diterpene kaurenoids.
authors.affiliation: Department of Human Physiology, University of Durban-Westville, Private Bag X54001, Durban, South Africa. somova@pixie.udw.ac.za
authors.forename: L I
authors.initials: LI
authors.lastname: Somova
authors.forename: F O
authors.initials: FO
authors.lastname: Shode
authors.forename: K
authors.initials: K
authors.lastname: Moodley
authors.forename: Y
authors.initials: Y
authors.lastname: Govender
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology / Q000633:toxicity*; D001156:Artemia; D003326:Coronary Circulation / Q000187:drug effects; D004224:Diterpenes / Q000494:pharmacology / Q000633:toxicity*; D045786:Diterpenes, Kaurane; D004231:Diuresis / Q000187:drug effects*; D004232:Diuretics / Q000494:pharmacology / Q000633:toxicity*; D006439:Hemodynamics / Q000187:drug effects; D007928:Lethal Dose 50; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D013329:Structure-Activity Relationship; D014664:Vasodilation / Q000187:drug effects
chemical_list: D000959:Antihypertensive Agents; D004224:Diterpenes; D045786:Diterpenes, Kaurane; D004232:Diuretics; D010936:Plant Extracts; C002627:kaurene