Setamycin, a 16-membered macrolide antibiotic. Identification and nematocidal activity.

Setamycin which has been isolated by Omura et al.,1*^ is a macrolide antibiotic possessing activities against trichomonads, some fungi and Gram-positive bacteria. The morphological and physiological properties of its producing organism led to a new genus designated as Kitasatosporia setae of the order ActinomycetalesP Recently, many unusual 16-memBered macrolides4) such as hygrolidins,5»6) L681,110 antibiotics,7) bafilomycins,8>9) leucanicidin10) and L-l55,175 antibiotic,n) have been reported. Setamycin also has been estimated as a macrolide belonging to this family from its spectral data and biological properties. In this paper we wish to describe the identification and biological properties of setamycin. The molecular formula, C42H61NO12for setamycin was tentatively proposed by the elementary analysis and 13C NMRspectral data, in our previous paper.13 However, the molecular formula was revised to be C44H65NO13 from the sub-