Chemical Fingerprinting, Isolation and Characterization of Polyphenol Compounds from Heliotropium taltalense (Phil.) I.M. Johnst and Its Endothelium-Dependent Vascular Relaxation Effect in Rat Aorta.

Ruth E Barrientos,Alejandra Bravo,Adrián Paredes,Javier Palacios,Mario J Simirgiotis,Fredi Cifuentes,Jorge Bórquez

doi:10.3390/molecules25143105

Ruth E Barrientos, Alejandra Bravo + Show 5 more

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https://doi.org/10.3390/molecules25143105

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Abstract

Heliotropium taltalense is an endemic species of the northern coast of Chile and is used as folk medicine. The polyphenolic composition of the methanolic and aqueous extract of the endemic Chilean species was investigated using Ultrahigh-Performance Liquid Chromatography, Heated Electrospray Ionization and Mass Spectrometry (UHPLC-Orbitrap-HESI-MS). Fifty-three compounds were detected, mainly derivatives of benzoic acid, flavonoids, and some phenolic acids. Furthermore, five major compounds were isolated by column chromatography from the extract, including four flavonoids and one geranyl benzoic acid derivative, which showed vascular relaxation and were in part responsible for the activity of the extracts. Since aqueous extract of H. taltalense (83% ± 9%, 100 μg/mL) produced vascular relaxation through an endothelium-dependent mechanism in rat aorta, and the compounds rhamnocitrin (89% ± 7%; 10−4 M) and sakuranetin (80% ± 6%; 10−4 M) also caused vascular relaxation similar to the extracts of H. taltalense, these pure compounds are, to some extent, responsible for the vascular relaxation.

Highlights

The endemic species Heliotropium taltalense (Phil.) I.M
To assess vascular relaxation of chemical substances, the rat aorta should first be pre-contracted with available agonists (e.g., KCl or phenylephrine), and the vascular contractile response must reach a plateau before adding the vascular relaxation substances [14]
Dietary flavones protect against cardiovascular disease [19], besides, rat aortas from flavonoid-treated animals showed good endothelium-dependent relaxations to acetylcholine, to a similar extent as those pretreated with the angiotensin-converting enzyme inhibitor, captopril [20]

Summary

Introduction

The endemic species Heliotropium taltalense (Phil.) I.M. Johnst. (Heliotropiaceae) called Monte negro in Chile has been used since pre-Hispanic times as an anti-inflammatory and to treat bone bruises [1]. The endemic species Heliotropium taltalense (Phil.) I.M. Johnst. (Heliotropiaceae) called Monte negro in Chile has been used since pre-Hispanic times as an anti-inflammatory and to treat bone bruises [1]. H. taltalense is a species with white and yellow flowers (Figure 1), which grows in the Chilean coastal area of Paposo valley at an altitude of 0–500 m above the sea level. Prevalence rates of hypertension are on the rise in developing countries [2]. Several vascular pathologies find their cause on inflammatory and Molecules 2020, 25, 3105; doi:10.3390/molecules25143105 www.mdpi.com/journal/molecules besides, rat aortas from flavonoid-treated animals showed good endothelium-dependent relaxations to acetylcholine, to a similar extent as those pretreated with the angiotensin-converting enzyme inhibitor, captopril [20]

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