Anti-biofilm activity against Staphylococcus aureus MRSA and MSSA of neolignans and extract of Piper regnellii

Many infections worldwide are associated with bacterial biofilms. The effects of isolated neolignans (conocarpan and eupomathenoid-5) and the dichloromethane extract of Piper regnellii (Miq.) C. DC., Piperaceae, were tested against isolates of methicillin-resistant Staphylococcus aureus and methicillin-sensitive S. aureus biofilms and S. aureus planktonic cells. The dichloromethane extract presented better results than isolated neolignans against all of the biofilms tested, with a minimum inhibitory concentration <400 μg/ml for preformed biofilms and minimal biofilm inhibitory concentration of 15.6 μg/ml for biofilm formation. The minimum inhibitory concentration to planktonic cells was <12.5 μg/ml. These results indicate a good effect of the dichloromethane extract against methicillin-resistant S. aureus and methicillin-sensitive S. aureus biofilms and efficient prophylaxis.