RESUMEN
Assay-guided fractionation of an antitubercular extract obtained from Lessonia nigrescens yielded the phytosterol saringosterol as its active component. No appreciable toxicity against Vero cells was observed for this compound. Saringosterol was also synthesized by oxidation of fucosterol. The MIC values for antitubercular activity of saringosterol and its 24S and 24R epimers were determined as 0.25, 1, and 0.125 microg/mL.
Asunto(s)
Antituberculosos/aislamiento & purificación , Mycobacterium tuberculosis/efectos de los fármacos , Phaeophyceae/química , Estigmasterol/análogos & derivados , Estigmasterol/aislamiento & purificación , Animales , Antituberculosos/síntesis química , Antituberculosos/química , Antituberculosos/farmacología , Células Cultivadas/efectos de los fármacos , Chile , Chlorocebus aethiops , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Relación Dosis-Respuesta a Droga , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Oxidación-Reducción , Estereoisomerismo , Estigmasterol/síntesis química , Estigmasterol/química , Estigmasterol/farmacología , Células Vero/efectos de los fármacosRESUMEN
Xanthorrizol (1) and 4-(1',5'-dimethylhex-4'-enyl)-2-methylphenol (2) were identified as the principal antimicrobial components of a CH(2)Cl(2)-MeOH (1:1) extract derived from Iostephane heterophylla. Compound 2 is a new natural product, but has been synthesized. Both compounds exhibited low level activity (MICs of 16-32 microg/mL) against methicillin-resistant staphylococci and vancomycin-resistant enterococci. They were either inactive or poorly active against Gram-negative bacteria and yeast. Mechanistic studies performed in Escherichia coli imp suggested nonspecific inhibition of DNA, RNA, and protein synthesis by both of these compounds. Compound 1 was tested in an in vivo model; it did not provide protection to mice infected with Staphylococcus aureus.
Asunto(s)
Antiinfecciosos/aislamiento & purificación , Antifúngicos/aislamiento & purificación , Asteraceae/química , Fenoles/aislamiento & purificación , Plantas Medicinales/química , Animales , Antibacterianos , Antiinfecciosos/química , Antiinfecciosos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Candida albicans/efectos de los fármacos , ADN/biosíntesis , ADN/efectos de los fármacos , Modelos Animales de Enfermedad , Farmacorresistencia Microbiana , Enterococcus faecium/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Femenino , Espectroscopía de Resonancia Magnética , México , Ratones , Ratones Endogámicos , Pruebas de Sensibilidad Microbiana , Fenoles/química , Fenoles/farmacología , Raíces de Plantas/química , Biosíntesis de Proteínas , Proteínas/efectos de los fármacos , ARN/biosíntesis , ARN/efectos de los fármacos , Espectrofotometría Ultravioleta , Staphylococcus aureus/efectos de los fármacos , Vancomicina/farmacologíaRESUMEN
Propolis from central Chile was investigated for its plant origin by microscopical analysis of pollen grains and leaf fragments found in the sample. The pollen grains that appear with significant higher frequency in the sample corresponded to four native and two introduced species, whereas leaf fragments corresponded to four native species. Seventeen phenolic compounds that belong to the phenylpropane, benzaldehyde, dihydrobenzofuran, or benzopyran classes, were isolated from an organic extract that was found to have a moderate growth inhibitory activity against Mycobacterium avium, M. tuberculosis, and two strains of Staphylococcus aureus. The components responsible for activity were determined.