39. Flavonoids from Pterocaulon alopecuroides with antibacterial activity.

ALARC¨®N, S.R., CARRIZO FLORES, R., OCAMPOS, S., LUCATTI, A., FLORES GALLEGUILLO, L., TONN, C., SOSA, V.E.

PLANTA MEDICA

Georg Thieme Verlag KG

Lugar: Stuggart New York; Año: 2008 vol. 74 p. 1463 - 1467

0032-0943

Three flavonoids, (2R,3R)-5,4¡ä-dihydroxy-3¡ä-Omethyl-7-(¦Ã,¦Ã-dimethylallyloxy)dihydroflavonol 1, (2R,3R)-5,7,4¡ä-trihydroxy-3¡ä-O-methyl-6-(¦Á,¦Á-dimethylallyl) dihydroflavonol 2, and (2R,3R)-5,7,4¡ä-trihydroxy-6-(¦Á,¦Á-dimethylallyl)dihydroflavonol 3, together with three known flavonoids (4¨C6), were isolated from the aerial parts of Pterocaulon alopecuroides. The structures of the compounds were determined by mass and by 1 D and 2 D NMR spectroscopy. Screening of the antibacterial activity of all six compounds was conducted by a disc diffusion test against Bacillus cereus, Bacillus subtilis, Salmonella typhimurium and Proteus mirabilis. The minimum inhibitory concentration (MIC) of the active compounds (2, 3, 4, 6) was determined by a microdilution assay. These compounds were active only against both Gram (+) bacteria with MIC values ¡Ü 200 ¦Ìg/mL.R,3R)-5,4¡ä-dihydroxy-3¡ä-Omethyl-7-(¦Ã,¦Ã-dimethylallyloxy)dihydroflavonol 1, (2R,3R)-5,7,4¡ä-trihydroxy-3¡ä-O-methyl-6-(¦Á,¦Á-dimethylallyl) dihydroflavonol 2, and (2R,3R)-5,7,4¡ä-trihydroxy-6-(¦Á,¦Á-dimethylallyl)dihydroflavonol 3, together with three known flavonoids (4¨C6), were isolated from the aerial parts of Pterocaulon alopecuroides. The structures of the compounds were determined by mass and by 1 D and 2 D NMR spectroscopy. Screening of the antibacterial activity of all six compounds was conducted by a disc diffusion test against Bacillus cereus, Bacillus subtilis, Salmonella typhimurium and Proteus mirabilis. The minimum inhibitory concentration (MIC) of the active compounds (2, 3, 4, 6) was determined by a microdilution assay. These compounds were active only against both Gram (+) bacteria with MIC values ¡Ü 200 ¦Ìg/mL.