Ethyl Acetate Fraction from Leandra dasytricha (A. Gray) Cong. Leaves Promotes Vasodilatation and Reduces Blood Pressure in Normotensive and Hypertensive Rats.

Rita De Cassia Vilhena Da Silva,Arquimedes Gasparotto Junior,Denise Brentan Silva,Priscila De Souza,Valdir Cechinel-Filho,Vanessa Samudio Santos Zanuncio,Eleine Renata Bidinha,Luísa Nathália Bolda Mariano,Camila Leandra Bueno De Almeida

doi:10.1155/2021/7203934

Abstract

Leandra dasytricha (A. Gray) Cong. is widely distributed in the south of Brazil and is commonly used for cardiovascular and kidney ailments. For this study, we used male Wistar normotensive rats (NTRs) and spontaneously hypertensive rats (SHRs) to verify the effects of the ethyl acetate fraction (EAF) obtained from L. dasytricha leaves on isolated aorta relaxation and in the arterial blood pressure. The EAF was analyzed by LC-DAD-MS, and several components were annotated, including hydrolysable tannins, triterpenes, and O- and C-glycosylated dihydrochalcones, such as the most intense ion peak relative to C-hexosyl phloretin (nothofagin; compound number 13). The EAF caused a concentration and endothelium-dependent relaxation of the aorta in both NTRs and SHRs. This effect was abolished in the endothelium-denuded aorta. L-NAME, a nonselective nitric oxide synthase inhibitor, and ODQ, a soluble guanylate cyclase inhibitor, entirely blocked the EAF-induced relaxation. The presence of a muscarinic receptor antagonist or a cyclooxygenase inhibitor did not alter the EAF's effectiveness in relaxing the aorta. The preincubation with tetraethylammonium, a Ca2+-activated K+ channel blocker, and with 4-aminopyridine, a voltage-dependent K+ channel blocker, significantly interfered with the EAF's relaxation. However, the incubation with glibenclamide, an ATP-sensitive K+ channel blocker, and barium chloride, an inward-rectifier K+ channel blocker, did not interfere with the EAF-induced relaxation. The EAF treatment also caused a dose-dependent decrease in the mean arterial pressure, systolic arterial pressure, and diastolic arterial pressure of both NTRs and SHRs, without significantly interfering with heart rate values. In conclusion, this study demonstrated the EAF-induced vasorelaxant and hypotensive actions, primarily dependent on the endothelium function and mainly with the participation of the nitric oxide and Ca2+-activated and voltage-dependent K+ channels.

Highlights

According to data from the American Heart Association (AHA), heart diseases are the leading causes of death globally
Chemical Analyses by LC-DAD-MS. e ethyl acetate fraction (EAF) was analyzed by LC-DAD-MS, and twenty-one compounds were annotated (Table 1 and Figure 1). e compounds were annotated based on their spectral data (MS, MS/MS, and UV) compared with data reported in the literature, and standards were used to confirm some compounds when possible
E analyses by LC-DAD-MS from EAF revealed several compounds that had not been reported previously in L. dasytricha; we here expanded the chemical knowledge of this medicinal species

Summary

Introduction

According to data from the American Heart Association (AHA), heart diseases are the leading causes of death globally. Ere are several classes of antihypertensive drugs; the failure to effectively control blood pressure can occur for several reasons, including suboptimal treatment and disease progression, with nonadherence to the treatment being responsible for 50 to 80% of unsatisfactory pressure reduction [4,5,6]. For these reasons, cardiovascular disease risks remain increased in hypertensive patients. Nothofagin induced endothelium-dependent vasodilation in renal arteries [13]

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Conclusion