RESUMO
Three tropane alkaloids, 1-3, were isolated from Erythroxylum caatingae, i.e., 6ß-benzoyloxy-3α-[(4-hydroxy-3,5-dimethoxybenzoyl)oxy]tropane (1), a new tropane alkaloid, along with the known alkaloids 3α,6ß-dibenzoyloxytropane (2) and 6ß-benzoyloxy-3α-[(3,4,5-trimethoxybenzoyl)oxy]tropane (catuabine B; 3). Their structures were determined by 2D- ((1) H and (13) C) NMR. By LC/ESI-MS/MS analysis of the fractions of alkaloids 1-3, it was possible to detect five more alkaloids, 4-8, two of these, 4 and 8, possibly being new natural products. X-Ray crystallography of the chloride derivate of 1, i.e., 6ß-benzoyloxy-3α-(4-hydroxy-3,5-dimethoxybenzoyloxy)tropane hydrochloride (1a) confirmed the structure of 1. Cytotoxicity was tested against the cell lines HEp-2, NCI-H292, and KB for the MeOH extract and alkaloid 3, and antitumor activity was tested against Sarcoma 180 only for the MeOH extract.
Assuntos
Antineoplásicos Fitogênicos/química , Erythroxylaceae/química , Tropanos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/toxicidade , Linhagem Celular Tumoral , Cristalografia por Raios X , Humanos , Espectroscopia de Ressonância Magnética , Conformação Molecular , Caules de Planta/química , Tropanos/isolamento & purificação , Tropanos/toxicidadeRESUMO
Erythroxylum, the most representative genus of the Erythroxylaceae family, presents tropane alkaloids as main constituents. This class of compounds greatly contributes to the chemotaxonomic characterization of plants of this genus, and it has important medical uses and shows toxic effects. This review describes 186 tropane alkaloids in the 35 species of Erythroxylum distributed worldwide. In addition, a compilation of their (13)C-NMR spectral data is presented.