Susceptibility of some clinical isolates of Staphylococcus aureus to fractions from the aerial parts of Leuzea carthamoides

The antimicrobial activity of the dichloromethane extract from aerial parts of Leuzea carthamoides DC. was tested in vitro against 19 Staphylococcus aureus strains (ATCC 25923, CNCTC Mau 43/60, clinical isolates). The extract was fractionated by column chromatography on silica gel into six fractions (petroleum ether, toluene, dichloromethane, ethyl acetate, methanol and water). The minimum inhibitory concentrations (MICs) of the fractions ranged from 64 to 1024 µg/mL. An ethyl acetate fraction (EA 1) with the widest range of activity inhibited all of the strains with MIC in the range 128–512 µg/mL. This fraction exhibited potent activity against strains which showed associated resistance to oxacillin, ciprofloxacin and erythromycin.