Isolation and Structure Determination of a New Lumichrome Glycoside Isolated from a Soil Streptomyces sp. KCB16C001

Abstract

Microbial studies of soil samples collected at Ochang, Korea led to the isolation of the actinobacterium Streptomyces sp. KCB16C001. Subsequent LC/MS analysis of the culture extract for dereplication purposes enabled the identification of a new metabolite ochangoside (1), whose chemical structure was determined to be 1-( α -L-rhamnosyl)-lumichrome by scale-up purification and structure elucidation procedures based mainly on NMR and MS spectroscopic data. Determination of the stereochemistry of the sugar moiety was achieved by LC/MS analysis of the sugar derivatized with L-cysteine methyl ester and o -tolyl isothiocyanate. Our results represent a rare example of natural lumichrome glycoside with a sugar unit attached at N −1.