Reversal of Hypertension and Amelioration of Oxidative Stress by Persea americana and Allium sativum in Experimentally-Induced Hypertensive Wistar Rats

Aim: This study evaluated the antihypertensive and antioxidant effects of hexane, ethyl acetate and methanol extracts of Persea americana and Allium sativum in experimentally-induced hypertensive Wistar rats. Study Design: Experimental Research.  Place and Duration of Study: Department of Veterinary Pharmacology and Toxicology, University of Ibadan (Animal House), between May 2019 and December 2019. Methodology: The experiment was carried out in 85 rats randomly divided into 17 groups. Group 1 were normotensive rats while hypertension was induced in groups 2-16 by unilateral nephrectomy and inclusion of NaCl (1%) in drinking water. Group 17 had abdominal incision without nephrectomy (sham). Treatment groups were administered P. americana or A. sativum extracts at 20 mg/kg or 50 mg/kg dose and standard antihypertensives; lisinopril or hydrochlorothiazide. Results: Results of the experiment showed treatment of hypertensive rats with 50 mg/kg of A. sativum hexane and P. americana methanol extract caused the most significant decrease in blood pressure compared to normotensive rats. Various extracts of these two plants elevated antioxidants levels (GPx, GST, GSH and SOD) in the brain, heart, kidney and liver significantly while H2O2 and MDA were significantly decreased compared to untreated hypertensive rats. NO, an important neurotransmitter for normal endothelial function was also restored in the extract-treated rat, as a deficiency contributes greatly to the development of hypertension. Conclusion: The study concluded that P. americana and A. sativum do not only lower blood pressure. The plants also inhibited generation of free radicals by enhancing the antioxidant system and mopped up generated free radicals demonstrated by decline in H2O2 and MDA levels. These plants have been shown in this study to contain potential drug candidates which can be proposed for treatment of hypertension.