Pladienolides, new substances from culture of Streptomyces platensis Mer-11107 II.: Physico-chemical properties and structure elucidation

In the course of our screening using fermented broth from soil microorganisms, novel metabolites (pladienolides), possessing inhibitory activity against vascular endothelial growth factor (VEGF) expression and cancer cell proliferation, were isolated from Streptomyces platensis Mer-11107. Pladienolides A (1), B (2), C (3), D (4), E (5), F (6), and G (7) were found to be novel 12-membered macrolides by spectroscopic studies including H-1, C-13 NMR, HMQC, HMBC, and NOE experiments. Pladienolides are unusual 12-membered macrolides having a long side chain at the carbon that bears a lactone oxygen.