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 ef flux 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 ef flux mechanisms. Copyright 2003 John Wiley & Sons, Ltd.