title: Flavonoids from Praxelis clematidea R.M. King and Robinson modulate bacterial drug resistance.
abstract: Chemical studies of Praxelis clematidea R.M. King & Robinson resulted in the isolation of six flavones: Apigenine, genkwanine, 7,4'-dimethylapigenin, trimethylapigenin, cirsimaritin and tetramethylscutellarein, which were tested for their toxicity against Staphylococcus aureus SA-1199B, a strain possessing the NorA efflux pump. Efflux pumps are integral proteins of the bacterial membrane and are recognized as one of the main causes of bacterial drug resistance, since they expel antibiotics from the cell. The inhibition of this transporter is one form of modulating bacterial resistance to antimicrobial drugs. The flavones tested did not show any significant antibacterial activity against the Staphylococcus aureus strain used, but were able to modulate bacterial drug resistance. This property might be related to the degree of lipophilicity of the flavones conferred by the methoxyl groups, since 4',5,6,7 tetramethoxyflavone the most methoxylated compound, reduced the minimal inhibitory concentration of the drug 16-fold.
authors.affiliation: Laboratory of Pharmaceutical Technology, Federal University of Paraíba, João Pessoa, PB 58051, Brazil. gabriela.lam@gmail.com
authors.forename: Gabriela Lemos de Azevedo
authors.initials: GL
authors.lastname: Maia
authors.forename: Vivyanne dos Santos
authors.initials: Vdos S
authors.lastname: Falcão-Silva
authors.forename: Pedro Gregório Vieira
authors.initials: PG
authors.lastname: Aquino
authors.forename: João Xavier
authors.initials: JX
authors.lastname: de Araújo-Júnior
authors.forename: Josean Fechine
authors.initials: JF
authors.lastname: Tavares
authors.forename: Marcelo Sobral
authors.initials: MS
authors.lastname: da Silva
authors.forename: Luis Cezar
authors.initials: LC
authors.lastname: Rodrigues
authors.forename: José Pinto
authors.initials: JP
authors.lastname: de Siqueira-Júnior
authors.forename: José Maria
authors.initials: JM
authors.lastname: Barbosa-Filho
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D019659:Asteraceae / Q000737:chemistry*; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D005419:Flavonoids