Five new epothilone metabolites from Sorangium cellulosum strain So0157-2

With the aim of identifying more novel natural epothilone derivatives produced by the epothilones A and B producing strain Sorangium cellulosum strain So0157-2, a large-scale fermentation (5000 1) of the strain was carried out. As a result, five new epothilone variants (1-5) were isolated from the fermentation broth. Their structures were established as 3-alpha-D-arabinofuranosides of epothilones A (1), B (2), D (3), C-9 (4) and 8-demethyl epothilone A (5) by extensive NMR analysis and chemical methods. Bioassay results showed that compounds 1 and 2 had a weaker cytotoxic activity than did epothilone B. The Journal of Antibiotics (2009) 62, 483-487; doi:10.1038/ja.2009.55; published online 3 July 2009