CJ-21,164, a new D-glucose-6-phosphate phosphohydrolase inhibitor produced by a fungus Chloridium sp.

A new D-glucose-6-phosphate phosphohydrolase (G6Pase) inhibitor, CJ-21,164 (I) was isolated from the fermentation broth of the fungus Chloridium sp. CL48903. The structure was elucidated to be a novel tetramer of the salicylic acid derivatives by spectroscopic analyses. Compound I inhibited G6Pase in rat liver microsomes with an IC50 of 1.6 mum. Glucose output from hepatocytes isolated from rat liver was inhibited when I was present in the incubation medium, consistent with the role of I as a G6Pase inhibitor.