Cyclo(dehydroshistidyl-L-tryptophyl), an inhibitor of nitric oxide production from a fungal strain, Fb956

Abstract

In the course of screening for nitric oxide inhibitors in activated microglial BV-2 cells, cyclo(dehydrohistidyl-L-tryptophyl) was isolated from solid-state fermentation cultures of an unidentified fungal strain, Fb956. Its structure was determined by spectroscopic methods including 2D NMR and chiral TLC analyses. Cyclo(dehydrohistidyl-L-tryptophyl) was found to have an inhibitory activity on nitric oxide production with an IC50 of 6.5 μM in activated BV-2 cells. The structure determination and biological activity of cyclo (dehydrohistidyl-L-tryptophyl) was reported for the first time in this study.