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Nowadays, biofouling is responsible for enormous economic losses in the maritime sector, and its treatment with conventional antifouling paints is causing significant problems to the environment. Biomimetism and green chemistry approaches are very promising research strategies for the discovery of new antifouling compounds. This study focused on the red alga Sphaerococcus coronopifolius, which is known as a producer of bioactive secondary metabolites. Fifteen compounds, including bromosphaerol (1), were tested against key marine biofoulers (five marine bacteria and three microalgae) and two enzymes associated with the adhesion process in macroalgae and invertebrates. Each metabolite presented antifouling activity against at least one organism/enzyme. This investigation also revealed that two compounds, sphaerococcinol A (4) and 14R-hydroxy-13,14-dihydro-sphaerococcinol A (5), were the most potent compounds without toxicity towards oyster larvae used as non-target organisms. These compounds are of high potential as they are active towards key biofoulers and could be produced by a cultivable alga, a fact that is important from the green chemistry point of view.

WOS:000516538500002; 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 mu g ml(-1) 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.