Amphypterygium adstringens Anacardic Acid Mixture Inhibits Quorum Sensing-controlled Virulence Factors of Chromobacteriurn violaceum and Pseudomonas aeruginosa

Background and Aims. Quorum sensing (QS) is a process of bacterial cell-cell communication that controls a large number of systems affecting pathogenicity. Interrupting this communication system can provide nonvirulent pathogenic bacteria. The aim of this study was to evaluate the anti-quorum sensing (anti-QS) potential of an anacardic acids mixture isolated from Amphipterygium adstringens, a medicinal plant known as "cuachalalate", to prevent the onset of bacterial infections as an alternate to antibiotics. Methods. Initially we investigated the anti-QS activity of A. adstringens hexane extract (HE) by the inhibition of violacein production in Chromobacterium violaceum. From the active HE, an anacardic acid mixture (AAM) was obtained. The anti-quorum sensing activity of AAM was investigated by the rhamnolipid and pyocyanin production constraint as well as decrease of elastase activity, all being quorum sensing-controlled virulence factors expressed in the pathogenic bacteria Pseudomonas aeruginosa. Results. HE induced a 91.6% of inhibition of the violecin production at 55 mu g/mL concentration, whereas AAM showed 94% of inhibition at 166 mu g/mL. In both cases, inhibition of violacein production did not affect the viability of the bacterium. AAM inhibited pyocyanin (86% at 200 mu g/mL) and rhamnolipid (91% at 500 mu g/mL) production in a dose/response form and decrease the elastase (75% at 500 mu g/mL) activity in P. aeruginosa without affecting its development. Conclusions. Because an anacardic acids mixture isolated from A. adstringens demonstrated anti-QS, it could be further exploited for novel molecules to treat the emerging infections of antibiotic-resistant bacterial pathogens. (C) 2013 IMSS. Published by Elsevier Inc.