Antineoplastic agents. Part 409: Isolation and structure of montanastatin from a terrestrial actinomycete

A Montana soil actinomycete, Streptomyces anulatus, produced (1x10(-2)% yie ld) a new cancer cell growth inhibitory cyclooctadepsipeptide named montana statin (1) accompanied by the potent anticancer antibiotic valinomycin (2) in very high (5.1%) yields. Valinomycin but not montanastatin inhibited gro wth of a number of pathogenic bacteria and fungi. Interpretation of high-fi eld (500 MHz) NMR and high-resolution FAB mass spectral data allowed assign ment of the structure cyclo-(D-Val-L-Lac-L-Val-D-Hiv) to montanastatin. Val inomycin (2) was also isolated from actinomycetes cultured from a tree bran ch and animal feces collected in Malaysia. Streptomyces exfoliatus, isolate d from the tree branch, was found to contain valinomycin in 1.6% yield, whi le the fecal isolate, S. anulatus, gave valinomycin in 0.9% yield. (C) 1999 Elsevier Science Ltd. All rights reserved.