Hymenaea rubriflora Ducke stem bark extract has vasorelaxant and contractile inhibition capacity

Abstract

We investigated the vasodilatory effects of Hymenaea rubriflora Ducke stem bark extract (HR- HAc). Vascular reactivity of the aortic rings of Wistar rats was tested by in vitro cumulative doses (0.1 - 729 μg/mL). Rats (n=5) were treated with 25 (G25), 50 (G50) and 100 (G100) mg/ kg of HR-HAc or saline (control group - CG) for four weeks. An in vitro assay resulted in dose-dependent relaxation of the aortic rings with functional endothelium, which was inhibited in the presence of L-NAME. Rings of the treated animals increased acetylcholine relaxing potency at all doses, with a greater effect on G50 (pD2 = 7.8±0.1, Emax = 95.6±1.1) and a decreased contractile potency to phenylephrine in G25 (pD2 = 6.9±0.06, Emax = 61.5±6.0%) and G50 (pD2= 6.6±0.06, Emax = 71.0±8.5%) when compared to the CG in the presence and absence of endothelium (pD2= 6.4± 0.1, 6.4±0.1 and 6.9±0.1, respectively). Cumulative doses of nitroprusside resulted in increased relaxing potency in all treated groups and maintained Emax at 100%. It is concluded that HR-HAc has vasorelaxant capacity and inhibitory vascular contraction activity applied either directly to aortic rings or after treatment with in vivo supplementation, which places this extract as a potential nutraceutical or pharmacological agent for treating diseases associated with vascular dysfunction.

Keywords
Antioxidant; Aorta; Hymenaea rubriflora ducke; Nitric oxide; Vasorelaxation