I. Isolation and characterization of the transformation products of maridomycin III

Three transformation products of maridomycin (MDM) III, a macrolide antibiotic, by Streptomyces lavendulae were isolated by silica gel and alumina chromatography, and designated as spots 1 (starting MDM III), 2, 3 and 4, in the order of their decreasing Rf values on thin-layer chromatogram. By mass- and NMR-spectrometry and thin-layer chromatography, spot 2 was identified as 18-dihydro-MDM III, spot 3 as 4''-depropionyl-MDM III, and spot 4 as 18-dihydro-4''-depropionyl-MDM III. The relationship between starting MDM III and these transformation products were also discussed.