Pseudoverticin B, a novel geldanamycin analog obtained as new cell cycle inhibitor from Streptomyces pseudoverticillus YN17707

Abstract

Pseudoverticin B (1), a novel naturally occurring geldanamycin analog with cell cycle inhibitory activity, was isolated from the fermentation broth of Streptomyces pseudoverticillus YN17707, together with the known ansamycin antibiotic, hydroquinone geldanamycin (2), through bioassay-guided fractionation procedures. The structure of compound 1 was elucidated by spectroscopic methods, being characterized by an ansa bridge, same as that in geldanamycin and a novel hydroquinone-derived moiety. Compounds 1 and 2 arrested the cell cycle of tsFT210 cells at the G0/G1 phase with the minimum inhibitory concentration values of 10.1 and 20.2 μmolL⁻¹, respectively.

Keywords:

• Pseudoverticin B
• hydroquinone geldanamycin
• geldanamycin
• cell cycle inhibitor
• Streptomyces pseudoverticillus

Acknowledgments

We are grateful to Dr. H. Osada, head of the Antibiotics Laboratory, the Institute of Physical and Chemical Research (RIKEN), Japan, for his kind gift of the tsFT210 cell line.

Disclosure statement

No potential conflict of interest was reported by the authors.