Activity of Zanthoxylum clava-herculis extracts against multi-drug resistant methicillin-resistant Staphylococcus aureus (mdr-MRSA)

In a continuing search for compounds with antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA) possessing multidrug efflux systems, we have demonstrated activity associated with extracts from Southern prickly ash bark, Zanthoxylum clava-herculis. Bioassay-guided isolation of an alkaloid extract led to the characterization of the benzo[c]phenanthridine alkaloid chelerythrine as the major active principle. This compound exhibited potent activity against strains of MRSA, which were highly resistant to clinically useful antibiotics via multidrug efflux mechanisms.