Metabolic products of microorganisms. 224. Bafilomycins, a new group of macrolide antibiotics. Production, isolation, chemical structure and biological activity.

The bafilomycins A1, A2, B1, B2, C1 and C2, a new type of macrolide antibiotics with a 16-membered lactone ring, were isolated from the fermentation broth of three Streptomyces griseus strains (TU 1922, TU 2437, TU 2599) by ethyl acetate extraction and column chromatography on silica gel. The bafilomycins exhibit activity against Gram-positive bacteria and fungi. Physico-chemical data, chemical structures and biological activities are reported.