Metabolic products of microorganisms. 200. Isolation and characterization of niphithricins A, B, and elaiophylin, antibiotics produced by Streptomyces violaceoniger.

Fermentations of Streptomyces violaceoniger TU 905 produce the antifungal antibiotics niphithricins A, B, elaiophylin and nigericin. The niphithricins have been characterized as new macrolide antibiotics, and the previously unknown structure of elaiophylin was determined to be a macrodiolide. The niphithricins were biologically active against Gram-positive bacteria and fungi. The mode of action is attributed to an alteration of the membrane permeability.