Antibacterial activity of bark of Alnus pendula against methicillin-resistant Staphylococcus aureus.

BACKGROUND AND OBJECTIVES Methicillin-resistant Staphylococcus aureus (MRSA) infections are a rapidly growing health problem around the globe. Recently, there has been considerable interest in the use of plant materials as an alternative method to control pathogenic microorganisms. In this study we evaluated the antibacterial activity of bark of Alnus pendula against MRSA. MATERIALS AND METHODS The MIC determination was done using the microdilution broth method and bacterial growth was determined by measuring optical density using spectrophotometer. RESULTS Alnus pendula bark EtOH extract and fractions (F-1, -2, -3 and -4) were investigated against MRSA. The most active fractions (F-3 and F-4) led to the isolation of oregonin (ORE) and hirsutanone (HIR). These compounds were active against MRSA strains with minimum inhibitory concentrations (MICs) ranging from 31.25 to 250 microg/ml MIC and 2 MIC of HIR completely inhibited the growth of MRSA. CONCLUSIONS The bark EtOH extract of Alnus Pendula has potent antibacterial activity against MRSA.