Prospecção anti-incrustante de extratos orgânicos de Laurencia dendroidea J. AGARDH 1852 (Rhodophyta, Rhodomelaceae)

Abstract

Laurencia dendroidea corresponds to one of the red macroalgae species found along the Brazilian coast, widely studied due to its production of bioactive secondary metabolites (SM). The most investigated SM include sesquiterpenes, identified and characterized in several studies for their role as chemical mediators in biological interactions between species. These SM have shown antifouling activity against a wide range of organisms, although the underlying mechanisms are not fully understood. Notwithstanding biofouling process occurs naturally in marine environments, it represents inconvenience and economic damages when associated with submerged artificial structures, and its control through chemical products can lead to water contamination and harmful effects on non-target organisms. In this study, the antifouling activity of organic extracts, at natural concentration, of the red macroalgae L. dendroidea, collected from five locations along the southeastern Brazilian coast, were evaluated, namely: Armação dos Búzios (AZED) – RJ, Angra dos Reis (BISC) – RJ, Serra (MANG) – ES, Arraial do Cabo (FORN) – RJ and Paraty (VERM) – RJ. Two controls were used: a positive one, with copper sulfate (CuSO 4 ), and a negative one, with dichloromethane only (DCM). The antifouling activity was evaluated using the mussel Perna perna as model organism for ecological interaction between species. The results showed that all L. dendroidea extracts exhibited significant antifouling activity compared to the negative control. However, the extracts corresponding to AZED, BISC and VERM showed significant difference when compared to the CuSO 4 . There was no significant difference between the organic extracts in terms of antifouling activity, when compared to each other, nonetheless, the samples with the most promising prospect in inhibiting the biofouling process corresponded to the AZED and BISC extracts, which showed 0% of byssus threads attachment by the mussels. Among these, the BISC L. dendroidea extract was more promising, as it has showed higher antifouling potential and less toxicity to mussels, causing mortality in 27% of the exposed individuals. Although no significant difference was detected among the tested extracts regarding the macroalgae collection sites, the results suggest L. dendroidea as a promising source of antifouling SM with practical applications in the fouling prevention in submerged artificial structures.