Dereplicating secondary metabolites from Calothrix sp., Desertifilum tharense, and Leptolyngbya sp. using metabolomics

Abstract

Cyanobacteria produce several secondary metabolites, such as toxins and other natural products with antiviral, antifungal, algaecide, antioxidant, and antitumor properties. Previous studies have shown that extracts from Brazilian cyanobacteria that did not contain known toxins displayed biological activity in the brine shrimp assay. They included extracts from strains Calothrix sp. CCIBt3320, Desertifilum tharense CCIBt3265, and Leptolyngbya sp. CCIBt3338. Discovering bioactive molecules from cultured cyanobacteria involves extraction, pre-fractionation, bioassay testing, dereplication, isolation, and structural elucidation. The dereplication process consists of identifying known molecules in natural product samples, avoiding allocating time and resources to isolate already known compounds. Metabolomics tools, such as DAFdiscovery, can help prioritize compounds for dereplication by correlating spectrometric and spectroscopic data with bioassay results. The current project aims to evaluate the cytotoxicity of extracts and fractions against cancer cells and dereplicate secondary metabolites from Brazilian cyanobacteria. Dereplication will be assisted by DAFdiscovery for spectral prioritization, as well as metabolomics tools such as GNPS molecular networking, SNAP-MS and SIRIUS. Detailed manual analysis followed by extensive database search will be performed on selected data to determine chemical novelty aiming at prioritizing compounds for future isolation and structure elucidation.