Endophytic naphthopyrone metabolites are co‐inhibitors of xanthine oxidase, SW1116 cell and some microbial growths

Fractionation of the extract of Aspergillus niger . IFB‐E003, an endophyte in Cyndon dactylon , gave four known compounds naphtho‐γ‐pyrones rubrofusarin B, fonsecinone A, asperpyrone B and aurasperone A, which were further investigated biologically. Rubrofusarin B was shown to be cytotoxic to the colon cancer cell line SW1116 (IC 50 : 4.5 μg ml −1 ), and aurasperone A inhibitory on XO (xanthine oxidase) (IC 50 : 10.9 μmol l −1 ). Moreover, the four naphtho‐γ‐pyrones exhibited growth inhibitions against the five test microbes with MICs ranging in between 1.9 and 31.2 μg ml −1 . The present recognition of rubrofusarin B and aurasperone A as strong co‐inhibitors on XO, colon cancer cell and some microbial pathogens is of significance for the imperative discovery of new relevant therapeutic agents.