Research Article Endothelium-Dependent Effects of Echinodorus grandiflorus (Cham. & Schltdl.) Micheli Mediated by M3-Muscarinic and B2-Bradykininergic Receptors on Peripheral Vascular Resistance and Its Modulatory Effects on K+ Channels in Mesenteric Vascular Beds Enaile Salviano de Carvalho, 1 Cleide Adriane Signor Tirloni, 1 Rhanany Alan Calloi Palozi, 1 Maysa Isernhagen Schaedler, 1 Lucas Pires Guarnier, 1 Aniely Oliveira Silva, 1 Jonas da Silva Mota, 2 Claudia Andréa Lima Cardoso, 2 Márcio Eduardo de Barros, 1 and Arquimedes Gasparotto Junior 1 1 Faculdade de Ciˆ encias da Sa´ ude, Universidade Federal da Grande Dourados, Dourados, MS, Brazil 2 Centro de Estudos em Recursos Naturais, Universidade Estadual de Mato Grosso do Sul, Dourados, MS, Brazil Correspondence should be addressed to Arquimedes Gasparotto Junior; arquimedesgasparotto@gmail.com Received 28 August 2018; Accepted 19 December 2018; Published 2 January 2019 Academic Editor: Danilo Ranieri Copyright © 2019 Enaile Salviano de Carvalho et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Tis work provides the frst demonstration that ethanolic extract (EEEG) obtained from Echinodorus grandiforus leaves (EEEG) and its butanolic fraction (ButFr) has important vasodilatory efects on isolated mesenteric vascular beds (MVBs). First, the EEEG was obtained and a liquid-liquid fractionation was performed. EEEG and its resulting fractions were analyzed by high-performance liquid chromatography. Ten, the vasodilatory efects of EEEG and their respective fractions were evaluated. Finally, the molecular mechanisms involved in the vasodilator responses of the EEEG and ButFr were also investigated. EEEG vasodilator response was estimated at ∼11 and 18 mm Hg at doses of 0.1 and 0.3 mg, respectively. Moreover, it was found that ButFr was able to induce an expressive dose-dependent vasodilator response in MVBs. Te PP reduction values for doses of 0.1 and 0.3 mg were ∼10 and 28 mm Hg, respectively. Endothelium removal or inhibition of nitric oxide and prostaglandin synthase (by L-NAME plus indomethacin) inhibited the vasodilatory efects induced by ButFr or EEEG. Te peak efect of ButFr and EEEG doses (0.1 and 0.3 mg) was decreased by ∼100% (p < 0.001). Te association of atropine plus HOE-140 fully inhibited EEEG and ButFr-induced vasodilation (p < 0.001). Moreover, perfusion with nutritive solution containing 40 mM KCl or previous treatment with tetraethylammonium completely blocked vasodilation induced by ButFr (p < 0.001). Tis study showed that EEEG and its ButFr have important vasodilatory efects by endothelial M3-muscarinic and B2-bradykininergic receptors inducing nitric oxide and prostacyclin release followed by K+ channels activation in the vascular smooth muscle. 1. Introduction In recent years, Echinodorus grandiforus (Cham. & Schltdl.) Micheli (Alismataceae) has gained prominence in Brazil. Te infusion of its leaves has been used an antihypertensive and diuretic agent by diferent native populations in South Amer- ica for many years. In fact, due to its extensive ethnobotanical use in Brazil [1, 2], the genus Echinodorus was included as a hypolipidemic and diuretic agent according to the herbal form of Brazilian Pharmacopoeia [3, 4]. Several preclinical pharmacological studies have pre- sented E. grandiforus as a promising species for the treatment of cardiovascular diseases. Available data have shown that dif- ferent preparations obtained from the species could present diuretic [5, 6], antiedematous [7], antihypertensive [6–8], and vasodilatory efects [9]. Hindawi Evidence-Based Complementary and Alternative Medicine Volume 2019, Article ID 4109810, 11 pages https://doi.org/10.1155/2019/4109810