Antihypertensive and antidiabetic activities of Erythrina senegalensis DC (Fabaceae) stem bark aqueous extract on diabetic hypertensive rats

Abstract

Ethnopharmacological relevance: Erythrina senegalensis is traditionally used in Cameroon for its relaxing and hypoglycemic properties in the treatment of cardiovascular diseases and diabetes.

Aim of the study: High blood pressure and diabetes mellitus are frequently linked. These pathologies represent major risk factors for cardiovascular and renal diseases. The present study was designed to evaluate the antidiabetic and antihypertensive activity of the stem bark of Erythrina senegalensis aqueous extract in male hypertensive diabetic rats (HDR).

Materials and methods: Hypertension and diabetes were induced by oral administration of sucrose (15%) and ethanol (40°) at doses of 1.5 g/kg and 5 g/kg respectively for 30 days, followed by an intravenous injection of streptozotocin (STZ; 40 mg/kg). A control group of 5 rats received distilled water (10 mL/kg) followed by intravenous injection of 0.9% NaCl (1 mL/100 g). HDR were divided into 4 groups of 5 rats each according to their blood glucose level and continued to receive ethanol in association with: distilled water (10 mL/kg); group I, metformin (200 mg/kg)+nifedipine (10 mg/kg); group II, plant extract (100 and 200 mg/kg) group IV and V, respectively for 28 days. At the end of the treatment, hemodynamic parameters were recorded by the direct method. Animals were sacrificed; blood and organs (aorta, heart, liver, and kidneys) were collected for biochemical and histological analysis. Phytochemistry and HPLC-DAD-HRESI-MS were used to determine the major compounds of the extract.

Results: The administration of sucrose, alcohol, and STZ resulted in a significant increase in blood glucose, hemodynamic parameters, and body weight loss. A significant decrease in pancreatic islets size, nitrite, GSH, SOD and catalase activity was observed in HDR. There was also a significant increase in serum triglycerides, total cholesterol, creatinine, bilirubin, and transaminases activity in HDR. The aqueous extract of E. senegalensis, as well as the metformin + nifedipine combination, significantly improved all these parameters. HPLC coupled to both diode array and mass spectrometry detectors revealed the presence of 15 compounds and 11 of them were identified.

Conclusion: These results suggest that the aqueous extract of E. senegalensis possess antihypertensive, hypoglycemic, hypolipidemic, cardiomodulator and antioxidant properties involved in the improvement of the metabolic disorders found in HDR. This may be due at least in part to the presence of Erysenegalensein (D, O, N, E), Warangalone, senegalensin and 6,8-diprenylgenistein identified in the extract.

Keywords: Antioxidant; Diabetes; Erythrina senegalensis; Hypertension; Rat.