title: 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.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Physiology, College of Medicine, University of Nigeria, Enugu Campus, Enugu, Enugu State, Nigeria.
authors.forename: Daniel Chukwu
authors.initials: DC
authors.lastname: Nwachukwu
authors.affiliation: Department of Medicine, Enugu State University of Science and Technology, Enugu, Enugu State, Nigeria.
authors.forename: Eddy Ikemefuna
authors.initials: EI
authors.lastname: Aneke
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, University of Benin, Benin City, Edo State, Nigeria.
authors.forename: Leonard Fidelis
authors.initials: LF
authors.lastname: Obika
authors.affiliation: Department of Ophthalmology, University of Nigeria Teaching Hospital, Enugu, Enugu State, Nigeria.
authors.forename: Nkiru Zuada
authors.initials: NZ
authors.lastname: Nwachukwu
mesh_terms: D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000097:blood; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000494:pharmacology / Q000627:therapeutic use*; D004311:Double-Blind Method; D000075222:Essential Hypertension; D031584:Hibiscus / Q000737:chemistry*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D017706:Lisinopril / Q000494:pharmacology / Q000627:therapeutic use; D008875:Middle Aged; D009549:Nigeria; D007703:Peptidyl-Dipeptidase A / Q000097:blood; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System / Q000187:drug effects
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D010936:Plant Extracts; D000450:Aldosterone; D017706:Lisinopril; D007703:Peptidyl-Dipeptidase A; D012083:Renin
keywords: Aldosterone and essential hypertension; Hibiscus sabdariffa; angiotensin-converting enzyme; lisinopril; renin