Antimicrobial evaluation of selected naturally occurring oxyprenylated secondary metabolites

<p>This study tested the antimicrobial activity of eight selected naturally occurring oxyprenylated secondary metabolites against <i>Staphylococcus aureus</i> ATCC 29213, <i>S. epidermidis</i> ATCC 35984, <i>Escherichia coli</i> ATCC 8739, <i>Pseudomonas aeruginosa</i> ATCC 9027 and <i>Candida albicans</i> ATCC 10231. Results showed a moderate antimicrobial activity. The most active compounds were 3-(4-geranyloxyphenyl)-1-ethanol (<b>4</b>) and 3-(4-isopentenyloxyphenyl)-1-propanol (<b>5</b>) that were tested on mature and in-formation biofilms of all micro-organisms, moreover the cytotoxic activity was evaluated. Except for <i>S. epidermidis</i>, both compounds reduced significantly (<i>p</i> < 0.05) the microbial biofilm formation at 1/2 MIC and 1/4 MIC, in particular, compounds <b>4</b> and <b>5</b> at each concentration, inhibited <i>E. coli</i> biofilm formation to a greater extent, the biofilm formation was never more than 44% in respect to the control, moreover both compounds showed a low cytotoxic effect. Oxyprenylated derivatives may be of great interest for the development of novel antimicrobial therapeutic strategies and the synthesis of semi-synthetic analogues with anti-biofilm efficacy.</p>