Chemistry 

The crude microbial extracts are initially purified on reverse phase C18 resin, Supelco Diaion HP20 resin or normal phase silica gel column chromatography and then further purified on reverse phase high performance liquid chromatography (HPLC) to obtain pure compounds. The gross structures of the natural products are determined from mass spectrometry, one- and two-dimensional nuclear magnetic spectroscopy (NMR), UV/Vis and IR infrared spectroscopy. The absolute stereochemistries of compounds are obtained by chemical derivation methods (Mosher or Marfey) and/or by X-ray analysis where appropriate.

     Silica gel column                     Reverse phase HPLC