From Broad-Spectrum Biocides to Quorum Sensing Disruptors and Mussel Repellents: Antifouling Profile of Alkyl Triphenylphosphonium Salts

30 páginas, 13 figuras, 4 tablas.-- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited‘Onium’ compounds, including ammonium and phosphonium salts, have been employed as antiseptics and disinfectants. These cationic biocides have been incorporated into multiple materials, principally to avoid bacterial attachment. In this work, we selected 20 alkyl-triphenylphosphonium salts, differing mainly in the length and functionalization of their alkyl chains, in fulfilment of two main objectives: 1) to provide a comprehensive evaluation of the antifouling profile of these molecules with relevant marine fouling organisms; and 2) to shed new light on their potential applications, beyond their classic use as broad-spectrum biocides. In this regard, we demonstrate for the first time that these compounds are also able to act as non-toxic quorum sensing disruptors in two different bacterial models (Chromobacterium violaceum and Vibrio harveyi) as well as repellents in the mussel Mytilus galloprovincialis. In addition, their inhibitory activity on a fouling-relevant enzymatic model (tyrosinase) is characterized. An analysis of the structure-activity relationships of these compounds for antifouling purposes is provided, which may result useful in the design of targeted antifouling solutions with these molecules. Altogether, the findings reported herein provide a different perspective on the biological activities of phosphonium compounds that is particularly focused on, but, as the reader will realize, is not limited to their use as antifouling agentsThis study was supported by the Spanish Ministry of Economy and Competitiveness (http:// www.mineco.gob.es/), SAF2011-28883-C03-01 (JJF), CTQ2011-28417-C02-01/BQU (VSM), AGL2010- 16464 (JMFB), MAT2013-40852-R (FL); Spanish Ministry of Education, Culture and Sport (http://www. mecd.gob.es/portada-mecd/), CEI 10/00018 (MN)Peer reviewe