Isolation and identification of biologically active natural products from marine ascidians

Marine ascidians are known to be a valuable source of structurally diverse secondary metabolites and many of these have exhibited potent biological activites. As part of our ongoing search for anticancer natural products, prefractionated extracts from a large collection of tropical plants, marine invertebrates, and microbial isolates were tested in a variety of molecularly-targeted high-throughput screening assays to evaluate their biological activity. Extracts from a number of different colonial ascidians (Ascidiacea) showed activity in the screens and were subjected to bioassay-guided fractionation and detailed chemical characterization. Structures of the resulting active compounds were determined by spectroscopic analysis and the interpretation of 1D and 2D NMR, and mass spectrometry data. The structural elucidation and biological characterization of a variety of marine ascidian metabolites will be described.