Mollisianitrile, a new antibiotic from Mollisia sp. A59-96.

Mollisianitrile (1), a new antibiotic was isolated from the fermentation broth of Mollisa sp. A59-96 together with the two known isocoumarins 2 and 3. 1 exhibited antimicrobial, cytotoxic, and phytotoxic activities. 1 contains a reactive propiolonitrile moiety which is believed to be responsible for its antibiotic activities. Upon incubation with L-cysteine the biological activity was lost.