Cardiovascular effects of Urtica dioica L. (Urticaceae) roots extracts: in vitro and in vivo pharmacological studies

J Ethnopharmacol. 2002 Jun;81(1):105-9. doi: 10.1016/s0378-8741(02)00055-7.


Urtica dioica (Urticaceae) is a plant principally used in the traditional medicine of oriental Marocco as antihypertensive remedy (J. Ethnopharmacol., 58 (1997), 45). The aim of this work was to evaluate a possible direct cardiovascular action of the plant and to investigate its mechanism of action. In aortic preparations with intact and functional endothelial layer, pre-contracted with KCl 20 mM or norepinephrine 3 microM, the crude aqueous and methanolic extracts of the plant roots, as well as purified fractions elicited a vasodilator action. Nevertheless, the vasodilator activity was not present in aortic rings without endothelial layer. In aortic rings with intact endothelial layer, the vasorelaxing effect was abolished by L-NAME, a NO-biosynthesis inhibitor, and ODQ, a guanylate cyclase inhibitor. Furthermore, potassium channel blockers (TEA, 4-aminopyridine, quinine, but not glybenclamide) antagonized the vasodilator action of the purified fraction F1W of U. dioica. The same fraction produced a marked decrease of inotropic activity, in spontaneously beating atria of guinea-pig, and a marked, but transient, hypotensive activity on the blood pressure of anaesthetized rats. It is concluded that U. dioica can produce hypotensive responses, through a vasorelaxing effect mediated by the release of endothelial nitric oxide and the opening of potassium channels, and through a negative inotropic action.

MeSH terms

  • Animals
  • Aorta / drug effects
  • Aorta / physiology
  • Blood Pressure / drug effects
  • Cardiovascular Agents / chemistry
  • Cardiovascular Agents / isolation & purification
  • Cardiovascular Agents / pharmacology*
  • Cardiovascular System / drug effects*
  • Dose-Response Relationship, Drug
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / physiology
  • Guinea Pigs
  • Logistic Models
  • Male
  • Plant Extracts / pharmacology*
  • Plant Roots / chemistry*
  • Rats
  • Rats, Wistar
  • Urtica dioica / chemistry*
  • Vasodilation / drug effects


  • Cardiovascular Agents
  • Plant Extracts