Ameliorative Effect of Morinda Lucida on L‐nitro Arginine Methyl Ester (L‐name) Induced Hypertension in Male Wistar Rats

Hypertension is a chronic cardiovascular disease of extreme and important global concern. It has been established as a leading cause of death especially in humans. The aim of this study was to evaluate the possible antihypertensive effect of a common locally available plant Morinda lucidaagainst L-Nitro-Arginine-Methyl-Ester (L-NAME)-induced hypertension in male Wistar rats. Forty-eight rats were used for the experiment. They were divided into six groups labelled A-F, each containing eight animals. The animals were dosed for six weeks with group A being the control group (normotensive) given feed and water ad libitun; Group B animals were administered L-NAME only, 40 mg/kg (hypertensive); Groups C, D and E were simultaneously treated with L-NAME (40 mg/kg) and Morinda lucida extract in increasing doses of 100 mg/kg, 200 mg/kg and 400 mg/kg, respectively, while Group F were given lisinopril at 20 mg/kg for a period of 6 weeks. From the result, there was significant increase in systolic, diastolic, and mean arterial blood pressure in the hypertensive group compared to the normotensive group and hypertensive treated groups. Hypertension caused significant (p<0.05) increases in oxidative stress markers, including malondialdehyde (MDA), protein carbonyl (PC), hydrogen peroxide (H2 O2 ), while reducing the activities of superoxide dismutase (SOD), and serum nitric oxide (NO) levels. Also, serum myeloperoxidase (MPO), blood urea nitrogen and creatinine were increased with high expression of cardiac injury biomarkers such as cardiac troponin and angiotensin 2 type 1 receptor. These indicated oxidative stress, cardiac damage because of hypertension, most especially in the untreated hypertensive group. The co-treatment of hypertensive rats with Morinda lucida extract caused reduction in markers of oxidative stress and inflammation and normalized blood pressure parameters. The findings from this study suggest the possibility of using Morinda lucida extract as a novel antihypertensive agent.