Isolation of new polyketide metabolites, linearolides A and B, from Streptomyces sp. RK95-74.

Although all Streptomyces strains are now thought to have 20-30 gene clusters for secondary metabolite biosynthesis, we cannot actually identify so many kinds of metabolites from one strain by conventional methods. Using Streptomyces sp. RK95-74, previously found as a cytotrienin producer, we searched new metabolites other than cytotrienin derivatives. Following the cultivation with new media and the peak-guided fractionation, we have found new compounds with new polyketide scaffold, named linearolides A and B.