Secondary metabolites by chemical screening. 15. Structure and absolute configuration of naphthomevalin, a new dihydro-naphthoquinone antibiotic from Streptomyces sp.

In the course of our chemical screening we detected a new naphthoquinone, naphthomevalin, in the culture broth of a Streptomyces sp.(strain Go 28) besides a number of already knownmetabo-lites^.After isolating from a soil sample collected in Strathgordon, Australia, the strain Go 28 was cultivated in 1-liter flasks at 28°C for 72 hours, using malt extract 1%, glucose 0.4% and yeast 0.4% as a culture medium.The culture broth could be separated by filtration, the mycelium and culture filtrate were subsequently extracted with acetoneethyl acetate and ethyl acetate, respectively.The isolation of naphthomevalin from the resulting raw products has been successful by using silica