Trichophycin A, a Cytotoxic Linear Polyketide Isolated from a Trichodesmium thiebautii Bloom

Matthew Bertin, University of Rhode Island
Paul G. Wahome
Paul V. Zimba
Haiyin He
Peter D.R. Moeller

Abstract

In an effort to isolate and characterize bioactive secondary metabolites from Trichodesmium thiebautii blooms, collected cyanobacteria biomass was subjected to bioassay-guided extraction and fractionation using the human colon cancer cell line HCT-116, resulting in the isolation and subsequent structure characterization of a linear polyketide trichophycin A (1). The planar structure of 1 was completed using 1D and 2D NMR spectroscopy and high-resolution electrospray ionization mass spectrometry (HRESIMS). Trichophycin A was moderately toxic against the murine neuroblastoma cell line Neuro-2A (EC₅₀: 6.5 μM) and HCT-116 cells (EC₅₀: 11.7 μM). Trichophycin A was significantly more cytotoxic than the previously isolated polyketides trichotoxin A and trichotoxin B. These cytotoxicity observations suggest that toxicity may be related to the polyol character of these polyketide compounds.