Anti-hypertensive effects of Callisia fragrans extract on Reno-vascular hypertensive rats

ABSTRACT Objectives This study aims to investigate the anti-hypertensive effects of aqueous extract of Callisia fragrans and their underlying mechanism using a two-kidney one-clip (2K1C) model of reno-vascular hypertension in rats. Methods The reno-vascular hypertensive rats were treated with C. fragrans leaf extract (100 and 500 mg/kg; p.o.) and a reference drug, captopril (20 mg/kg; p.o.), for 4 weeks. The blood pressure and heart rate were recorded using a tail-cuff. The heart weight, left ventricular wall thickness, and serum creatinine and urea levels were measured. A spectrophotometric assay was used to analyze the angiotensin-converting enzyme (ACE) inhibition activity of the extract and the reference drug. The total volume and the concentration of sodium, potassium, and chloride in urine samples were evaluated. Results C. fragrans extract significantly reduced both systolic and diastolic blood pressures in the reno-vascular hypertensive rats. No significant difference in the heart rate was observed between each animal group. C. fragrans extract reduced the 2K1C-induced increase in the heart and body weight ratio and the left ventricular wall thickness. Moreover, the extract also attenuated the increase in serum urea induced by the 2K1C treatment. C. fragrans extract inhibited ACE activity in vitro with an IC50 of 20.97 ± 3.94 µg/ml. The urine output and urinary electrolyte excretion significantly increased in C. fragrans extract-treated rats. Conclusions These findings demonstrated that C. fragrans extract can mitigate hypertension and alleviate ventricular hypertrophy and renal dysfunction in reno-vascular hypertensive rats, at least in part via ACE activity inhibition and diuretic property.