Marine natural product antifoulants: Status and potential

This overview attempts to bring together a widely scattered and disparate literature on marine natural product antifoulants. In particular, studies that have focused on the screening of secondary metabolites are reviewed in the context of the development of new antifouling coatings. Despite considerable progress towards characterising compounds that inhibit settlement of micro‐ and/or macrofouling, evidence for an ecological role for these compounds is poor. Even if broad spectrum antifoulants of sufficient promise are discovered, major hurdles must be overcome before they can be commercially exploited. Not least are the need to procure sufficient material and the cost of registration. Given these constraints and the relatively small size of the marine coatings market, industrial investment in product research and development appears low. Notwithstanding these problems, some marine organisms are able to maintain a surface that is essentially free of epibionts. Fundamental research on natural antifouling mechanisms is now required. The information gained, in addition to ascertaining the relative importance of physical versus chemical defences to marine organisms, would provide a conceptual framework for the development of novel, and ideally nontoxic, coatings.