Hydroalcoholic extract and pure compounds from Senecio nutans Sch. Bip (Compositae) induce vasodilation in rat aorta through endothelium-dependent and independent mechanisms

Ethnopharmacological relevanceSenecio nutans Sch. Bip. (Compositae) is an endemic plant of South America, and is used in herbal medicine in Andean communities for treating acute mountain sickness. Currently, the direct effects of hydroalcoholic extract of S. nutans (HAE S. nutans) or its isolated compounds on the vascular system are not well described. The aim of this study was to determine the effects and mechanism of action of S. nutans on vascular function in healthy rats.Material and methodsSeven compounds were isolated from the HAE S. nutans, and their structures were characterized using spectroscopic techniques as 1D and 2D NMR, and mass spectrometry. Vascular reactivity experiments were carried out in rat aorta. S. nutans-dependent vasodilation and phenylephrine-dependent contraction were measured in endothelium-intact and endothelium-denuded aortic rings of male rats.ResultsSeven pure compounds were isolate from HAE S. nutans, but two pure compounds showed significant vasodilation in rat aorta: 4-hydroxy-3-(3-methyl-2-butenyl)acetophenone (compound E) and 5-acetyl-6-hydroxy-2-isopropenyl-2,3-dihydrobenzofurane (compound G). Although HAE S. nutans induced vasodilation in absence of endothelium, the vasodilation in intact aorta, via NO, was higher. HAE S. nutans reduced calcium-dependent contraction in endothelium-intact, but not in endothelium-denuded aortic rings.ConclusionHAE S. nutans and its isolated compounds caused vasodilation in rat aorta in absence of endothelium, suggesting its vasodilator properties is endothelium-dependent (NO) and or independent, and may involve a modulation of the calcium channels. This result is of clinical interest as potential therapy control of blood pressure.

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