A Standardized Method For Dereplication Of Bioactive Fractions Of Freshwater Cyanobacteria Extracts

Dereplication is a necessary part of natural product discovery programs. With the rate of rediscovery of bioactive compounds increasing in well studied organisms, the ability to quickly identify previously described natural products has expedited the discovery of novel natural products. Standardized dereplication procedures provide an efficient path to determining the novelty of a bioactive natural product and allows for the allocation of time and materials to compounds with novel structures as opposed to rediscovering previously known compounds. Utilizing a standardized dereplication procedure, our lab has successfully dereplicated a variety of bioactive fractions from extracts of freshwater Cyanobacteria. The method uses only two separation steps to isolate active compounds from an organic extract, creating fractions and subfractions. The separations are analyzed for bioactivity and bioactive subfractions are evaluated by mass spectrometry and ¹H NMR. Here we describe examples of dereplicated compounds to introduce our standardized dereplication procedure and show the effectiveness of a mass spectrometry and 1 H based method to dereplicate bioactive fractions of freshwater Cyanobacteria and isolate novel natural products.