Novel polyketide metabolites from Streptomyces rimosus mutant strain R1059

Abstract

Three novel polyketide metabolites were isolated from laboratory-scale fermentation of the Streptomyces rimosus mutant strain R1059. Structural elucidation of the compounds was based on NMR experiments. The compounds were characterized as naphthalene derivatives: (rel)-4β,8-dihydroxy-3α- hydroxymethyl-4α-methyl-1,2,3,4-tetrahydronaphthalene-1-one (1), 4ξ,8-dihydroxy-3-hydroxymethyl-4ξ-methyl-1,4-dihydronaphthalene-1-one (2) and (rel)-4β,8-dihydroxy-3α-O-[α-glucopyranosyl]hydroxymethyl- 4α-methyl-1,2,3,4-tetrahydronaphthalene-1-one (3). The compounds isolated appear to be derived via a shorter polyketide backbone than oxytetracycline (4), the normal end-product made by the parent of this strain. Compound 3 was the glucoside of 1 and must be formed as a post-PKS reaction by the activation of a glycosyl transferase, which has not been reported in this species before. © Japan Antibiotics Research Association.