Efomycine U, a new C 2 -asymmetric elaiophylin derivative from Streptomyces malaysiensis DSM 4137.

Chemical examination of an actinomycete strain Streptomyces malaysiensis DSM 4137 derived from a soil sample derived isolate Streptomyces sp . DSM 3816, yielded a new C 2 -asymmetric elaiophylin derivative efomycine U ( 1 ) and a known analogue halichoblelide D ( 2 ). These structures were unambiguously elucidated on the basis of extensive NMR spectroscopic and mass spectrometric analyses. All compounds isolated were subjected to antimicrobial, cytotoxic and immnosuppressive activities evaluation.