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.