One strain-many compounds (OSMAC) method for production of polyketides, azaphilones, and an isochromanone using the endophytic fungus Dothideomycete sp.

Abstract

Polyketides 1–6 were produced by a one strain-many compounds (OSMAC) approach using the endophytic fungus Dothideomycete sp. CRI7 as a producer. Metabolite production of the fungus Dothideomycete sp. CRI7 was sensitive to sources of potato and malt extract used for the preparation of PDB and Czapek malt media, respectively. Three hitherto unknown metabolites were obtained from the fungus CRI7 grown in PDB medium prepared from a commercial potato powder instead of fresh tubers of potato, while three others were obtained from the fungus cultivated in Czapek malt medium. Moreover, a source of malt extract used in the Czapek malt medium was found to influence metabolite production by the fungus CRI7. Structure elucidation of these compounds was achieved by analysis of spectroscopic data, as well as by single crystal X-ray analysis. Two of the compounds showed weak cytotoxic activity, while the remainders were inactive toward the cell lines tested. One compound exhibited radical scavenging activity with an IC50 value of 21.7μM, and inhibited aromatase with an IC50 value of 12.3μM.