Avaliação da diversidade química e do potencial biotecnológico de algas calcárias geniculadas

Abstract

The geniculate calcareous algae (Corallinales, Rhodophyta) produce secondary metabolites from several chemical classes, such as fatty acids, sterols, tannins, flavonoids, alkaloids, saponins, hydrocarbons, and carotenoids. They are responsible for a variety of bioactivity such as antioxidant, antifungal, antibacterial, anticancer, biostimulant, anti-inflammatory, and antifouling. The Chapter 1 investigated the intra/interspecific chemical diversity and antifouling potential of crude extracts of four species of geniculate calcareous algae (Arthrocardia flabellata, Cheilosporum sagittatum, Amphiroa beauvoisii, Jania crassa) against five strains of marine fouling bacteria and the mussel Perna perna. The results revealed inter/intraspecific chemical variability among samples of geniculate calcareous algae collected in nearby areas and under similar oceanographic conditions. All extracts were active against marine bacteria, with C. sagittatum - CsSI and A. beauvoisii - AbSCC extracts being the most promising. In addition to the mussel P. perna, the extract of C. sagittatum (CsSI) was the most active, with a 100% inhibition of bissos. In Chapter 2, crude extracts and fractions of the aforementioned species were tested for antimycobacterial (hypervirulent strain Mtb M299 and Mtb laboratory H37Rv), anti-inflammatory (TNF-α and NO), and cytotoxicity. The extracts of A. flabellata (MIC 50 de 4.6 ± 1.3 μg/mL) e J. crassa collected in Prainha (MIC 50 12.6 ± 1.4 μg/mL) were the most active in terms of antimycobacterial activity. In terms of TNF- and NO inhibitory capacity, the most active extracts were A. beauvoisii collected on the coast of Saco do Cherne (IC 50 25.2 ± 1.5) and C. sagittatum (IC 50 6.7 ± 1.3 μg/mL). Except for C. sagittatum, none of the extrats exhibited toxic effects. When all activities were considered, the fractions FJC1, FJC2, and FJC3 of J. crassa collected in Prainha, as well as the fractions FAF2, FAF3, and FAF4 of A. flabellata, were the most active. The most purified fraction (F29-40), obtained by countercurrent chromatography and containing palmitic acid as the most abundant substance, was also tested against the selected models and demonstrated inhibitory activity against both mycobacteria strains as well as NO and TNF-inhibitory capacity. Fatty acids, fatty acid esters, hydrocarbons, fatty alcohol, sterol, and benzenoid were among the chemical classes discovered in the extracts and fractions examined. The results obtained for extracts and fractions of the species J.crassa, A. beauvoisii, C. sagittatum, and A. flabellata collected in Arraial do Cabo are unprecedented in terms of chemical composition, intra-interspecific chemical variability, and activity against the tested models, providing more information about the chemical substances produced by this group of macroalgae and demonstrating their biotechnological potential, which may be the subject of future studies in the search for new bioactive substances.