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The leaves of Pluchea symphytfolia (Miller) Gilis (Asteraceae) are used by the Mixe indians (Oaxaca, Mexico) against stomach-ache, diarrhea, intestinal parasites, and externally against infections of the ear (1). Only sesquiterpenes derived from cuauthemone and thiopheneacetylenes have been isolated from this species (2). Guided by a gelatine precipitation assay, the new 1,3,4,5-tetracaffeoylquinic acid (1) and compound 2 were isolated from the EtOAc layer of an aqueous acetone extract of the air-dried aerial parts in yields of 0.3% and 0.1%, respectively. Their separation was achieved by CC on Sephadex LH-20 and on MCI-CHP 20 HP gel. The structures of 1 and 2 were established by 1H-NMR and 13C-NMR spectroscopy, including 2Dhomo and 2D-hetero NMR techniques, mass spectrometry, and by chemical degradation.

Structural identification of flavonoid aglycones with unsubstituted B rings is rather difficult using the classical techniques, especially with respect to chemotaxonomic studies when only minute amounts of substances are available. In the present work, the thin layer chromatography and high performance liquid chromatography behaviour of these substances has been evaluated, and correlations between structural features, Rf values and elution order (tR) have been established. In addition, their ultraviolet spectra in methanol have proved useful to ascertain substitution patterns and location of free hydroxyls. Additional Information can be obtained by analysis of the permethylated derivatives obtained by methylation of the naturally occurring compounds.