Anti-Hypertensive Effects of Anthocyanins from Hibiscus sabdarifa Calyx on the Renin-Angiotensin-Aldoslestrone System in Wistar Rats

Abstract

Hibiscus sabdariffa (HS) has gained attention as an anti-hypertensive agent. In the present study, we hypothesized that anthocyanins from HS may attenuate salt-induced hypertension in rats by suppressing the components of renin-angiotensin-aldoslestrone system (RAAS). Hypertension was induced in the rats by adding 8% NaCl in their diet for six weeks. Wistar rats (n=5 each) were randomly divided into seven groups. Group 1 was the normentensive control group and was fed with normal rat chew and water ad libitum; groups 2 and 3 served as hypertensive control (negative untreated and positive treated with captopril 30mg/kg respectively); groups 4, 5, and 6 served as treatment groups and were administered with graded doses of anthocyanins( 50, 100, 200mg/kg respectively) while group 7 received both 100mg anthocyanins and 30mg captopril per day for 4 weeks. Using HPLC, anthocyanins were isolated from HS calyx following standard protocol. Anthocyanins significantly (p<0.05) reduced blood pressure and heart rate in hypertensive rats in a dose dependent manner. The blood pressure reduction by anthocyanins was associated with a reduction in serum ACE and plasma aldosterone in the hypertensive rats. The effects of anthocyanins on blood pressure and on biomarkers of RAAS were similar to those of captopril, a reference anti-hypertensive drug. The results suggest that anthocyanins exerts a significant (p<0.05) anti-hypertensive potency on rats, probably mediated by the reduction in components of the RAAS. Keywords: hypertension, anthocyanins, renin, aldosterone, rats

Resveratrol and beyond: The Effect of Natural Polyphenols on the Cardiovascular System: A Narrative Review

“…As shown by Xu et al, intracranial infusion of anthocyanin extract decreased the sympathetic nervous system activity and reduced blood pressure in salt-induced hypertensive rats [329]. Furthermore, anthocyanins administered at 50, 100, or 200 mg/kg decreased systolic and diastolic blood pressure as well as heart rate in hypertensive rats in a dose-dependent manner, at least in part through RAAS inhibition [330].…”

Effects of Anthocyanins on Components of Metabolic Syndrome—A Review

“…Xu et al [ 179 ] showed that chronic infusion of anthocyanins into the paraventricular nucleus of rats with salt-induced hypertension reduced BP and peripheral sympathetic nerve activity. Anthocyanins from Hibiscus sabdariffa reduced salt-induced hypertension in rats by inhibiting components of the renin–angiotensin–aldosterone system [ 178 ]. Yamane et al [ 165 ] reported that supplementing a standard diet with 10% freeze-dried chokeberries reduced BP in spontaneously hypertensive rats.…”

Phytochemical Composition and Inhibitory Activities of Hibiscus sabdariffa and Cucumis sativus Infusions Against Angiotensin-Converting Enzyme

“…Previous studies reported that these phytochemical compounds showed inhibitory activities against ACE and could lower blood pressure. 7,27,[41][42][43][44] 33,45 The complexes caused the enzyme to lose its affinity to bind with the substrate, resulting in no conversion of angiotensin-I to angiotensin-II. 2 In addition, phenolic acids and anthocyanins in H. sabdariffa have a vasorelaxant effect, which helps lower blood pressure.…”