title: Flavonoids from Pterocaulon alopecuroides with antibacterial activity.
abstract: Three flavonoids, (2 R,3 R)-5,4'-dihydroxy-3'- O-methyl-7-(gamma,gamma-dimethylallyloxy)dihydroflavonol 1, (2 R,3 R)-5,7,4'-trihydroxy-3'- O-methyl-6-(alpha,alpha-dimethylallyl)dihydroflavonol 2, and (2 R,3 R)-5,7,4'-trihydroxy-6-(alpha,alpha-dimethylallyl)dihydroflavonol 3, together with three known flavonoids ( 4 - 6), 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 < or = 200 microg/mL.
authors.affiliation: Facultad de Ciencias Naturales, Universidad Nacional de Salta (UNSa), Salta, Argentina. ralarcon@unsa.edu.ar
authors.forename: Rosana
authors.initials: R
authors.lastname: Alarcón
authors.forename: Roberto Carrizo
authors.initials: RC
authors.lastname: Flores
authors.forename: Soledad
authors.initials: S
authors.lastname: Ocampos
authors.forename: Alejandro
authors.initials: A
authors.lastname: Lucatti
authors.forename: Laura Flores
authors.initials: LF
authors.lastname: Galleguillo
authors.forename: Carlos
authors.initials: C
authors.lastname: Tonn
authors.forename: Virginia
authors.initials: V
authors.lastname: Sosa
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D019659:Asteraceae / Q000737:chemistry*; D001419:Bacteria / Q000187:drug effects*; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D019906:Nuclear Magnetic Resonance, Biomolecular
chemical_list: D000900:Anti-Bacterial Agents; D005419:Flavonoids