O10 Beneficial effect of Phyllanthus amarus (Euphorbiaceae) on DOCA-salt-induced left ventricle cardiac hypertrophy and endothelial dysfunction in rats

Introduction Phyllanthus amarus is used in African traditional medicine to treat cardiovascular disorders such as hypertension. This study has evaluated the effect of an aqueous extract of Phyllanthus amarus (AEPA) on blood pressure, cardiac and endothelial function in the deoxycorticosterone acetate and high salt diet (DOCA-salt)-induced hypertensive rats. Methods Male Wistar rats were assigned into five groups including control, AEPA (100 mg/kg), DOCA-salt (50 mg/kg), and DOCA-salt + AEPA(100 or 300 mg/kg). Systolic blood pressure (SBP) was determined by tail-cuff plethysmography, left ventricle cardiac structure and function by echocardiography, vascular reactivity of main mesenteric artery rings using organ chambers, the vascular level of oxidative stress using dihydroethidine staining, and the level of proteins by immunofluorescence methods. Results After 5 weeks, the AEPA treatments (100 or 300 mg/kg/day) significantly lowered SBP in DOCA-salt hypertensive rats by about 24 and 21 mmHg, respectively. Echocardiography indicated that AEPA affected slightly cardiac function and reduced significantly the increased posterior and septum diastolic wall thickness and the left ventricle mass in hypertensive rats. AEPA improved the DOCA-salt-induced endothelial dysfunction, and the blunted nitric oxide- and endothelium-dependent hyperpolarization-mediated relaxations in mesenteric artery rings. AEPA treatments reduced the level of vascular oxidative stress and the expression level of target proteins (eNOS, COX-2, p22 phox ) in DOCA-salt rats. Conclusion The Phyllanthus amarus aqueous extract induced an antihypertensive effect associated with an improved cardiac structure and endothelial dysfunction in DOCA-salt hypertensive rats. Such a beneficial effect might involve the normalization of the level of vascular oxidative stress.