J Ethnopharmacol. 2003 Jun; 86(2-3): 181-5.

Chronic administration of aqueous extract of Hibiscus sabdariffa attenuates hypertension and reverses cardiac hypertrophy in 2K-1C hypertensive rats.

Odigie IP, Ettarh RR, Adigun SA.

Department of Physiology, College of Medicine of the University of Lagos, PMB 12003, Nigeria. ipodigie@yahoo.com

The effect of aqueous extract of petals of Hibiscus sabdariffa (HS) on the established stages of 2-Kidney, 1-Clip renovascular hypertension was investigated in Sprague-Dawley rats. Renovascular hypertension was induced by subjecting the animals to left renal artery clamping using a 0.2mm silver clip under ether anesthesia. Sham-operated (Sh-Op) rats served as controls.Six weeks after renal artery clamping, one group of hypertensive rats (blood pressure (BP) >140 mmHg) received HS (250 mg/kg/day) in drinking water (2K-1C+HS). The second group (2K-1C) and the sham-operated (Sh-Op) controls, received drinking water. BP was monitored weekly using rat-tail plethysmography.After 8 weeks, 2K-1C+HS had a reduction in systolic BP (139.6+/-1.6 mmHg) compared to 2K-1C (174+/-2.4 mmHg, n=5; P<0.001). No significant difference was found in BP of 2K-1C+HS and Sh-Op (139.6+/-1.6 mmHg versus 132+/-3.4 mmHg). A reduction in heart rate in 2K-1C+HS was observed (388+/-3.7 bpm versus 444+/-6.8 bpm in 2K-1C and 416+/-9.3 in Sh-Op, n=5; P<0.001). The hearts of 2K-1C were heavier than those of 2K-1C+HS (0.74+/-0.03 g versus 0.66+/-0.03 g, n=5; P<0.05). Cardiac weight of 2K-1C+HS was comparable to those of Sh-Op (0.57+/-0.04 g). Serum creatinine and plasma electrolytes were not different from controls.This study suggests that HS exhibits antihypertensive and cardioprotective effects in vivo and supports the public belief that HS may be a useful antihypertensive agent.