title: Two new cassane-type diterpenes from Calliandra californica with antituberculosis and cytotoxic activities.
abstract: From 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.
authors.affiliation: Departamento de Agronomía, Universidad Autónoma de Baja California Sur, La Paz, México. rosalba@uabcs.mx
authors.forename: Rosalba
authors.initials: R
authors.lastname: Encarnación-Dimayuga
authors.forename: Jorge
authors.initials: J
authors.lastname: Agúndez-Espinoza
authors.forename: Abraham
authors.initials: A
authors.lastname: García
authors.forename: Guillermo
authors.initials: G
authors.lastname: Delgado
authors.forename: Gloria María
authors.initials: GM
authors.lastname: Molina-Salinas
authors.forename: Salvador
authors.initials: S
authors.lastname: Said-Fernández
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D000995:Antitubercular Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D045744:Cell Line, Tumor / Q000187:drug effects; D004224:Diterpenes / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D007887:Fabaceae; D006801:Humans; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D018517:Plant Roots
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D000995:Antitubercular Agents; D004224:Diterpenes; D010936:Plant Extracts