Hypertension is a chronic medical condition. Because of its high incidence and morbidity, various classes of drugs and regimens have been proposed for the control of hypertension including medicinal plant extracts. Sarcocephalus pobeguinii is used by gabonese traditional healers to treat high blood pressure. We here by investigated the phytochemical constituents and preventive effects of the aqueous extract of S.pobeguiniiagainst N-nitro-L-Arginine Methyl Ester (L-NAME) ?induced hypertension in Wistar rats. Materials and Methods: T he plant extract was screened for the presence of various secondary metabolites by classic colorimetric methods. In preventive treatment, six groups of 5 rats each orally received: distilled water (10 mL/kg/day), L-NAME (50 mg/kg/day), L-NAME and extract (200 or 400 mg/kg/day), L-NAME and Esidrix (20 mg/kg/day), L-NAME and Furorese (40 mg/kg/day) during 4 weeks. At the end of the experimental period, blood pressure and heart rate were measured using the direct cannulation method. The effects of the plant extract were assayed using colorimetric methods. Results: The phytochemical screening showed the presence of alkaloids, cardiac glycosides, and compounds phenolic. The plant extract at 200 and 400 mg/kg/day significantly prevented (13.65%) the increase in arterial blood pressure. Administration of the plant extract led to the prevention of lipid profile increase in serum in L-NAME-induced hypertensive rats. S. pobeguinii extract (400 mg/kg) also significantly prevented the increase in ASAT (29.44%) and ALAT (12.98%). The extract ameliorates tissues biomarkers of oxidative stress. Conclusion: These results demonstrate that the extract of S. pobeguinii can prevent L-NAME-induced hypertension and oxidative stress in rats.