Isolation and Characterization of New Epothilone Analogues from Recombinant Myxococcus xanthus Fermentations

Nine new epothilone analogues (6−8, 10, 11a, 11b, 12, 13, and 15) were isolated from fermentations of Myxococcus xanthus strains engineered with modified polyketide synthase genes. The epothilone structures were elucidated primarily through interpretation of 1D and 2D NMR data. 4-Desmethyl-10,11-didehydroepothilone D (6) displayed activity against several tumor cell lines, including a multi-drug-resistant cell line.