Abstract

In Central Africa, stem bark from Guibourtia tessmannii is used in traditional pharmacopeia for the treatment of hypertension. The aim of this study was to scientifically verify the traditional use in the treatment of metabolic pathologies such as arterial hypertension and evaluated its pharmacological potential. Phytochemical tests were evaluated by standard method of laboratory. Antioxidant activities were determined by DPPH and FRAP scavenging methods and hypotensive activity was achieved by the invasive method. The results showed that the aqueous stem bark extract caused a hypotensive effect. Pretreatment on normotensive rats with atropine had provoked a significant hypotensive effect (p <0.05), suggesting that muscarinic receptors are involved in the hypotensive effect of the extract. Applying adrenaline or epinephrine did not abolish the hypotension caused by the extract, suggesting that α1 and β1 receptors are involved in the hypotensive induction. Furthermore, phytochemical analyses indicated that G. tessmannii stem barks exhibit high levels of polyphenols, high antioxidant activity index (AAI=1.53), and high chelating activity (3.65 ± 0.021 mmol EAA/g of extract).  Thus, the results suggest that G. tessmannii might be considered a natural resource for the formulation of treatments against hypertension and as an antioxidant.

Key words: Guibourtia tessmannii, plant extract, normotensive rat, hypertension, antioxidant, polyphenols.