Calpinactam, a new anti-mycobacterial agent, produced by Mortierella alpina FKI-4905

Calpinactam, a new anti-mycobacterial agent, was isolated from the culture broth of a fungal strain Mortierella alpina FKI-4905 by solvent extraction, octadecyl silane column chromatography and preparative HPLC. Calpinactam was active only against Mycobacteria among various microorganisms, including Gram-positive and Gram-negative bacteria, fungi and yeasts. Calpinactam inhibited the growth of Mycobacterium smegmatis and Mycobacterium tuberculosis with MIC values of 0.78 and 12.5 μg ml −1 , respectively.