Effects of aqueous extract of Hibiscus sabdariffa on the renin-angiotensin-aldosterone system of Nigerians with mild to moderate essential hypertension: A comparative study with lisinopril

Indian J Pharmacol. 2015 Sep-Oct;47(5):540-5. doi: 10.4103/0253-7613.165194.


Objectives: The present study investigated the effects of aqueous extract of Hibiscus sabdariffa (HS) on the three basic components of renin-angiotensin-aldosterone system: Plasma renin, serum angiotensin-converting enzyme (ACE), and plasma aldosterone (PA) in mild to moderate essential hypertensive Nigerians and compared with that of lisinopril, an ACE inhibitor.

Materials and methods: A double-blind controlled randomized clinical study was used. Seventy-eight newly diagnosed but untreated mild to moderate hypertensive subjects attending Medical Outpatients Clinic of Enugu State University Teaching Hospital, Enugu were recruited for the study. Those in Group A received placebo (150 mg/kg/day), Group B were given lisinopril (10 mg once daily) while those in Group C received aqueous extract of HS (150 mg/kg/day). After 4 weeks of treatment, the levels of plasma renin, serum ACE, and PA were determined.

Results: HS and lisinopril significantly (P < 0.001) reduced PA compared to placebo by 32.06% and 30.01%, respectively. Their effects on serum ACE and plasma renin activity (PRA) were not significant compared to placebo; they reduced ACE by 6.63% and 5.67% but increased plasma PRA by 2.77% and 5.36%, respectively.

Conclusion: HS reduced serum ACE and PA in mild to moderate hypertensive Nigerians with equal efficacy as lisinopril. These actions are possibly due to the presence of anthocyanins in the extract.

Keywords: Aldosterone and essential hypertension; Hibiscus sabdariffa; angiotensin-converting enzyme; lisinopril; renin.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Aldosterone / blood
  • Angiotensin-Converting Enzyme Inhibitors / pharmacology
  • Angiotensin-Converting Enzyme Inhibitors / therapeutic use
  • Antihypertensive Agents / pharmacology
  • Antihypertensive Agents / therapeutic use*
  • Double-Blind Method
  • Essential Hypertension
  • Hibiscus / chemistry*
  • Humans
  • Hypertension / drug therapy*
  • Hypertension / physiopathology
  • Lisinopril / pharmacology
  • Lisinopril / therapeutic use
  • Middle Aged
  • Nigeria
  • Peptidyl-Dipeptidase A / blood
  • Plant Extracts / pharmacology
  • Plant Extracts / therapeutic use*
  • Renin / blood
  • Renin-Angiotensin System / drug effects


  • Angiotensin-Converting Enzyme Inhibitors
  • Antihypertensive Agents
  • Plant Extracts
  • Aldosterone
  • Lisinopril
  • Peptidyl-Dipeptidase A
  • Renin