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

Heliotropium taltalenseis 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 ofH. taltalense(83% +/- 9%, 100 mu g/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 ofH. taltalense, these pure compounds are, to some extent, responsible for the vascular relaxation.