A pair of novel bisindole alkaloid enantiomers from marine fungus Fusarium sp. XBB-9

A preliminary research on the marine fungus Fusarium sp. XBB-9 resulted in a pair of novel bisindole alkaloid enantiomers, (+)- and (–)-fusaspoid A (1a/1b) and 12 diverse compounds. One strain many compound (OSMAC) method was used to enhance as many biosynthetic pathways as possible. The structures of the compounds were elucidated by spectroscopic analysis, and the absolute configuration of 1a was determined by X-ray single-crystal diffraction analysis. Compounds 1a and 1b were tested for cytotoxic activity against HCT-15, RKO cell lines, but were inactive. Compounds 1a and 1b were the first example of bisindole alkaloids isolated from fungus Fusarium sp. XBB-9.