Anti-methicillin resistant Staphylococcus aureus (MRSA) compounds isolated from Laurus nobilis

We found that an extract from Laurus nobilis L. (Lauraceae) leaves showed antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). We purified two flavonoids as the effective compounds and identified them as kaempferol 3-O-alpha-L-(2'',4''-di-E-p-coumaroyl)-rhamnoside (C2) and kaempferol 3-O-alpha-L-(2''-Z-p-coumaroyl-4''-E-p-coumaroyl)-rhamnoside (C3). Both compounds showed strong antibacterial activity not only against MRSA but also against vancomycin-resistant enterococci (VRE). There was low or no antibacterial activity of C2 and C3 for Streptococcus pneumoniae, Pseudomonas aeruginosa and Serratia marcescens.