The Sponge-Associated Fungus Eurotium chevalieri MUT 2316 and its Bioactive Molecules: Potential Applications in the Field of Antifouling.

The need for new environmentally friendly antifouling and the observation that many marine organisms have developed strategies to keep their surface free of epibionts has stimulated the search for marine natural compounds with antifouling activities. Sponges and in particular fungi associated with them represent one of the most appropriate sources of defence molecules and could represent a promising biomass for the supply of new antifouling compounds. The objective of this work was therefore to evaluate the antifouling potency of 7 compounds isolated from the sponge derived fungus Eurotium chevalieri MUT 2316. The assessment of their activity targeted the inhibition of the adhesion and/or growth of selected marine bacteria (5) and microalgae (5), as well as the inhibition of the mussel's byssus thread formation (tyrosinase activity). The 7 compounds showed bioactivity, with various levels of selectivity for species. Cyclo-L-Trp-L-Ala was the most promising active compound, and led to the inhibition, at very low concentrations (0.001 μg ml in 61.5% of cases), of adhesion and growth of all the microalgae, of selected bacteria, and towards the inhibition of tyrosinase. Promising results were also obtained for echinulin, neoechinulin A, dihydroauroglaucin and flavoglaucin, respectively, leading to inhibition of adhesion and/or growth of 9, 7, 8 and 8 microfouling species at various concentrations.