Two New Cassane-Type Diterpenes from Calliandra californica with Antituberculosis and Cytotoxic Activities
2006; Thieme Medical Publishers (Germany); Volume: 72; Issue: 8 Linguagem: Inglês
10.1055/s-2006-931587
ISSN1439-0221
AutoresRosalba Encarnación-Dimayuga, Jorge Agúndez-Espinoza, Abraham García, Guillermo Delgado, Gloria María Molina-Salinas, Salvador Said‐Fernández,
Tópico(s)Bioactive natural compounds
ResumoFrom the root of Calliandra californica two new cassane-type diterpenes were isolated and characterized, escobarine A (1) and B (2), which showed promising activities against two Mycobacterium tuberculosis strains. The microplate alamar blue assay was used to determine the minimum inhibitory concentrations (MIC) of 1 and 2 against M. tuberculosis H37Rv and the resistant CIBIN/UMF15 : 099 strains. The MIC of 1 against the resistant M. tuberculosis strain showed a value 8 times lower than that of rifampin. The structures of the bioactive constituents were established by extensive NMR data analyses (including 1D and 2D NMR). The relative configuration of 2 was confirmed by X-ray analysis and the absolute configurations of 1 and 2 were determined by the circular dichroism method. Additionally, 1 and 2 displayed remarkable cytotoxic activity when evaluated against five human tumor cell lines.
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