Caffeic acid derivatives and further compounds from Espeletia barclayana Cuatrec. (Asteraceae, Espeletiinae)

This work describes the isolation of seven (1-7) secondary metabolites from Espeletia barclayana (Asteraceae, Espeletiinae) and their identification by spectroscopic (NMR) and spectrometric (MS) techniques. Ten (8-17) additional compounds were identified based on their retention times, high-resolution mass spectrometry data, and comparison with reference substances or data from literature. The systematic significance of some of the identified substances - the sesquiterpene lactone longipilin acetate, four caffeoylquinic acids and two tri-caffeoylaltraric acids - is discussed with the aim of providing insights into the complex relationships among Espeletiinae taxa and its closest relatives. Five of the isolated metabolites {[}5-O-(E)-caffeoylquinic acid (1), 1,3-di-O-(E)-caffeoylquinic acid (2), 1,5-di-O-(E)-caffeoylquinic acid (3), 3,4-di-O-(E)-caffeoylquinic acid (4) and 3-O-methylquercetin 7-O-beta-glucopyranoside (7)] constitute new reports for the genus Espeletia and for the subtribe Espeletiinae. Chemical data suggest that Espeletiinae might have a closer relationship with Smtlllanthus than with Ichthyothere, i.e., the two genera suggested to be the sister groups of Espeletiinae based on molecular markers. (C) 2017 Elsevier Ltd. All rights reserved. (AU)