Prospecção de microalgas brasileiras: caracterização bioquímica, metabólitos especializados e bioatividade

Abstract

Microalgae, form a heterogeneous and polyphyletic group of photosynthetic microorganisms. Their primary and secondary metabolites have brought attention to this group as a source of natural products of commercial interest. Many metabolites are unique to microalgae. This chemical diversity offered by microalgae is a niche of opportunity for searching promising molecules, especially when several biological activities, such as antibacterial and anticancer action, have already been described and the group has been barely explored. Thus, this research sought to characterize the composition of primary and secondary metabolites of four microalgae, Ankistrodesmus arcuatus, Radiococcus sp, Sorastrum bengalicum and Chlorolobion braunii. A. arcuatus was noteworthy to produce lipids, which represent 39.59 % ± 5.72 % of its dry weight. The species C. braunii was noted in relation of proteins amount per culture volume, 0.00193 mg/mL. While S. bengalicum and Radiococcus sp had the highest percentage of carbohydrates, 2,3 ± 0,5 and 2,0 ± 1,0 µg/mL, respectively. The latter also had the highest content of total carotenoids. Regarding the analysis of secondary metabolite production, metabolomic analyses of algal extracts obtained in different growth phases were performed using mass spectrometry, employing UPLC-HRMS/MS. The species A. arcuatus showed the highest number of distinct metabolites in the exponential growth phase. The species S. bengalicum showed the greatest distinction of metabolites between exponential and stationary phases of growth. And the species C. braunii showed the greatest similarity. Our data suggest that the growth phase, among the compared growth phases, influences both the number and features themselves present in each species, representing a relevant factor in the discovery of novel molecules. Antimicrobial activity-guided dereplication identified potential features that may be compounds of interest, and with further technical analysis, they may lead to the identification of potentially novel chemical formulas.