Dereplication of Macrocyclic Trichothecenes from Extracts of Filamentous Fungi through UV and NMR Profiles

Macrocyclic trichothecenes, which have potent cytotoxicity, have been isolated from many different fungal species. These compounds were evaluated clinically by the U.S. National Cancer Institute in the 1970's and 1980's. However, they have yet to be advanced into viable drugs due to severe side effects. Our team is investigating a diverse library of filamentous fungi for new anticancer leads. To avoid re-isolating macrocyclic trichothecenes via bioactivity-directed fractionation studies, a protocol for their facile dereplication was developed. The method uses readily available photodiode array detectors to identify one of two types of characteristic UV spectra for these compounds. Also, diagnostic signals can be observed in the (1)H-NMR spectra, particularly for the epoxide and conjugated diene moieties, even at the level of a crude extract. Using these techniques in a complementary fashion, macrocyclic trichothecenes can be dereplicated rapidly.