In vivo Antioxidant and Vasodilating Activities of Gmelina arborea (Verberaceae) Leaves Hexane Extract

Abstract

The present study investigated the effects of Gmelina arborea hexane leaves extract on markers of oxidative stress and its vasorelaxant effects on isolated rat aorta, in order to postulate the possible mechanisms involved in the antihypertensive properties of the plant. To evaluate the antioxidant effects of the extract, rats were randomly divided into four groups of five rats each. With the exception to the group receiving Tween (2.5%), the other groups were treated either with NaCl (900mg/kg/day) alone, NaCl (900mg/kg/day) combined with vitamin C (5mg/kg/day) or Gmelina arborea extract (150mg/kg/day). At the end of eight weeks of treatment, animals were sacrificed and some organs as well as blood samples were collected for biochemical analysis. The in vitro vasodilating effects of the extract (0.5-1.5mg/ml) were evaluated using intact and denuded rat thoracic aortic rings or aorta pre-incubated in L-NAME (2µM), indomethacin (2µM) or glibenclamide (2µM) and contracted with phenylephrine (1µM). The in vivo effects of G. arborea hexane extract prevented both left ventricular and vascular hypertrophy, it also modulated lipid metabolism. Moreover, the extract prevented lipid peroxidation, increased superoxide dismutase and catalase activity as well as NO level. On isolated rat aortic rings, the extract induced concentration-dependent vasorelaxant effects. Extract-induced vasodilation was reduced by mechanical denudation of the endothelium as well as pre-treatment with L-NAME, indomethacin or glibenclamide. These results indicate that Gmelina arborea hexane extract possesses bioactive compounds with antioxidant and vasorelaxant properties.

Review of Natural Resources With Vasodilation: Traditional Medicinal Plants, Natural Products, and Their Mechanism and Clinical Efficacy

“…The extract of Globularia alypum (GA) also relieved diastolic PHE (2–4 ng mL −1 )-induced mesenteric artery contractions in rats, which was inhibited by endothelial removal or atropine, but not indomethacin (10 μM) or L-NAME (100 μM) ( Chokri et al, 2012 ). The extract of Gmelina arborea hexane leaves (GAE) produced vasodilatory effects in PHE (1 μM)-induced contractions which was reduced by L-NAME (2 μM), indomethacin (2 μM) and glibenclamide (2 μM) ( Wansi et al, 2012 ).…”

Effects of Gmelina arborea, Roxb (Verbenaceae) aqueous extract on arterial pressure of Wistar rats

“…Indeed, in vitro study on rat aortic rings showed a vasorelaxation effect of G. arborea, which is, in part, NO dependent (Wansi et al, 2012). G. arborea extract could thus act by reversing the inhibiting effect of L-NAME on NO synthase.…”

“…arborea extract induced a significant reduction of blood pressure when administrated to rats following 7 days treatment with L-NAME or during the 7 last days of a 14-days treatment with L-NAME. In a previous study investigating the effect of aqueous extract of G. arborea on a salt-induced hypertension in rat, single dose intravenous administration of the extract induced a dose dependent but transient decrease of rat blood pressure (Wansi et al, 2009). As the measurement of blood pressure 24 h after the last administration of L-NAME, the study data showed that repeated oral administration of G. arborea leaves extract could induce not only a transient, but also a sustained decrease of blood pressure.…”

“…One of those plants frequently used in folk medicine is Gmelina arborea. Except a previous work showing a transient reduction of rat blood pressure induced by an intravenous administration of G. arborea leaves extract (Wansi et al, 2009), no study on the effectiveness of this plant in the treatment of hypertension in human or in an animal model has been performed. The present work was therefore undertaken to study the effects of G. arborea leaves extracton blood pressure in hypertensive rats.…”

Effet de l’extrait méthanolique du fruit de Gmelina arborea sur les caractères du sperme, la morphométrie testiculaire et l’histopathologie chez le lapin exposé au cadmium

“…Gmelina arborea (White teak) is one of such plants and belongs to the Verbinaceae family. It has been screened and reported to possess derived compounds that have beneficial effect on immunity, fertility, antioxidant defence, increased metabolic activity, detoxifying and cleansing properties (Wansi et al, 2012). Therefore, investigations into the pharmacological validation of this less explored plant will go a long way in handling physiological and reproductive defects in animals arising from Cd toxicity through ingestion or inhalation.…”