Unlocking Biological Activity and Metabolomics Insights: Primary Screening of Cyanobacterial Biomass from a Tropical Reservoir

Cyanobacterial harmful algal blooms (CyanoHABs) can pose risks to ecosystems and human health worldwide due to their capacity to produce natural toxins. Nevertheless, the potential danger associated with numerous metabolites produced by cyanobacteria remains undisclosed. Only select classes of cyanopeptides have been extensively studied to yield substantial evidence regarding their toxicity, resulting in their inclusion in risk management and water quality regulations. Information about exposure concentrations, co-occurrence, and toxic impacts of several cyanopeptides remains largely unexplored. This research utilized LC-MS-based metabolomics to ascertain the chemical profile of environmental cyanobacterial biomass collected from a eutrophic reservoir in Brazil. Using NP Analyst and Data Fusion-based Discovery (DAFdiscovery) platforms, we examined the correlation between the various cyanopeptides identified in the cyanobacterial crude extract, fractions, and the acute toxicity of these samples against the Artemia. salina microcrustacean. Four classes of cyanopeptides were revealed through metabolomics: microcystins, microginins, aeruginosins, and cyanopeptolins. The bioinformatics tools showed high bioactivity correlation scores for compounds of the cyanopeptolin class, in some cases even higher than those attributed to microcystins. These results emphasize the pressing need for a comprehensive evaluation of the (eco)toxicological risks associated with different cyanopeptides, considering their potential for exposure. This work also demonstrates the feasibility of conducting risk assessments using a more efficient approach involving LC-MS/MS-based metabolomics and chemometric techniques that require less time and reagents.