ABSTRACT
The phytochemical study of Calea uniflora led to the isolation of nine phenolic compounds identified as noreugenin (1), ethyl caffeate (2), a mixture of butein (3) + orobol (4), α-hydroxy-butein (5), caffeic acid (6), butein 4'-O-glucopyranosyl (7), quercetin 3-O-glucopyranosyl (8) and 3,5-di-O-caffeoylquinic acid (9). The chemical identity of the isolates was established on the basis of NMR and physical data. The chemical shifts of 5 and 7 have been reassigned and all the isolates were tested against Leishmania amazonensis and Trypanosoma cruzi amastigotes. None of the metabolites showed promising leishmanicidal activity. However, 2 and the mixture of 3 and 4 demonstrated interesting trypanocidal effect with IC50 values of 18.27 and 26.53 µM, respectively. Besides, these compounds did not present cytotoxic effect towards THP-1 cells, and compound 2 was 3.5-fold more selective than the mixture of 3+4.
Subject(s)
Antiparasitic Agents/pharmacology , Asteraceae/chemistry , Phenols/pharmacology , Trypanocidal Agents/pharmacology , Animals , Humans , Leishmania mexicana/drug effects , Magnetic Resonance Spectroscopy , Plant Leaves/chemistry , Trypanosoma cruzi/drug effectsABSTRACT
Calea pinnatifida (R. Br.) Less., Asteraceae, is popularly known as “quebra-tudo”, “cipó-cruz” or “aruca”. This species is used in the folk medicine for the treatment of stomach pain, giardiasis and amoebiasis. The aim of this study was to isolate and identify chromenes from leaves of C. pinnatifida and evaluate their leishmanicidal activity. A fraction from leaves of C. pinnatifida was analyzed for their chemical constituents, resulting in the isolation and characterization of four known chromenes: 6-acetyl-7-hydroxy-2,2-dimethylchromene (1), 6-acetyl-7-methoxy-2,2-dimethylchromene (2), 6-(1-hydroxyethyl)-7-methoxy-2,2-dimethylchromene (3) and 6-(1-ethoxyethyl)-7-methoxy-2,2-dimethylchromene (4). Structure identification of isolated compounds involved analysis of spectral data of 1D and 2D-NMR. The isolated compounds are here reported for the first time in C. pinnatifida, and the chromenes 1 and 3 show a moderate leishmanicidal activity.