Structure and Activity of Ikarugamycin Derivatives Isolated from the Extracts of Actinomyctes Bacteria Cultures

As part of our continues study on marine derived organisms and bacteria we studied the extracts of marine Actinomyctes. Four natural products, presenting cytotoxic properties, were isolated from extracts of the Streptomyces sp. MCCB267 cultures. The cells were freeze-dried, extracted with ethyl acetate and separated by different chromatographic methods, including Sephadex LH-20 and HPLC chromatography. The anticancer activity of the extracts were screened during the purification process against the NCI - H460 Lung cancer Cell line using Sulforhodamine B (SRB) assay. The structure of the isolated compounds was determined by analysis of the 1D and 2D NMR spectra, high-resolution mass spectroscopy, UV spectra, IR spectra and optic rotation (α_D). Ikarugamycin and 28-N-methyl ikarugamycin were isolated from samples DMS-21, DMA-37-WD and DMA-37-D. 30-oxo-28-N-methyl ikarugamycin and clifednamide A were isolated from sample DMS-21. The structure elucidation and biological activity of the compounds will be presented.