Vascular mechanisms underlying the hypotensive effect of Rumex acetosa

Pharm Biol. 2018 Dec;56(1):225-234. doi: 10.1080/13880209.2018.1446031.


Context: Rumex acetosa L. (Polygonaceae) is well known in traditional medicine for its therapeutic efficacy as an antihypertensive.

Objective: The study investigates antihypertensive potential of crude methanol extract (Ra.Cr) and fractions of Rumex acetosa in normotensive and hypertensive rat models and probes the underlying vascular mechanisms.

Materials and methods: Ra.Cr and its fractions were tested in vivo on normotensive and hypertensive Sprague-Dawley rats under anaesthesia for blood pressure lowering effect. In vitro experiments on rat and Oryctolagus cuniculus rabbit aortae were employed to probe the underlying vasorelaxant mechanism.

Results: In normotensive rats under anaesthesia, Ra.Cr caused fall in MAP (40 mmHg) at 50 mg/kg with % fall of 27.88 ± 4.55. Among the fractions tested, aqueous fraction was more potent at the dose of 50 mg/kg with % fall of 45.63 ± 2.84. In hypertensive rats under similar conditions, extract and fractions showed antihypertensive effect at same doses while aqueous fraction being more potent, exhibited 68.53 ± 4.45% fall in MAP (70 mmHg). In isolated rat aortic rings precontracted with phenylephrine (PE), Ra.Cr and fractions induced endothelium-dependent vasorelaxation, which was partially blocked in presence of l-NAME, indomethacin and atropine. In isolated rabbit aortic rings pre-contracted with PE and K+-(80 mM), Ra.Cr induced vasorelaxation and shifted Ca2+ concentration-response curves to the right and suppressed PE peak formation, similar to verapamil, in Ca2+-free medium.

Discussion and conclusions: The data indicate that l-NAME and atropine-sensitive endothelial-derived NO and COX enzyme inhibitors and Ca2+ entry blocking-mediated vasodilator effect of the extract explain its antihypertensive potential.

Keywords: Calcium channel blocker; NO-mediated vasorelaxant; antihypertensive.

MeSH terms

  • Animals
  • Antihypertensive Agents / isolation & purification
  • Antihypertensive Agents / pharmacology*
  • Aorta, Thoracic / drug effects*
  • Aorta, Thoracic / metabolism
  • Blood Pressure / drug effects*
  • Calcium Channels / drug effects
  • Calcium Channels / metabolism
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Hypertension / drug therapy*
  • Hypertension / metabolism
  • Hypertension / physiopathology
  • Male
  • Methanol / chemistry
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase / metabolism
  • Phytotherapy
  • Plant Extracts / isolation & purification
  • Plant Extracts / pharmacology*
  • Plant Leaves
  • Plants, Medicinal
  • Prostaglandin-Endoperoxide Synthases / metabolism
  • Rabbits
  • Rats, Sprague-Dawley
  • Rumex* / chemistry
  • Solvents / chemistry
  • Vasodilation / drug effects*
  • Vasodilator Agents / isolation & purification
  • Vasodilator Agents / pharmacology*


  • Antihypertensive Agents
  • Calcium Channels
  • Plant Extracts
  • Solvents
  • Vasodilator Agents
  • Nitric Oxide
  • Nitric Oxide Synthase
  • Prostaglandin-Endoperoxide Synthases
  • Methanol

Grants and funding

This study was supported by funds made available by the Higher Education Commission (HEC) of Pakistan vide Grant No. [20-1554/R&D/10]