Purification, identification and activity of phomodione, a furandione from an endophytic Phoma species

Usnic acid and two of its derivatives, cercosporamide and phomodione, were isolated from culture medium of an endophytic Phoma sp. Cercosporamide was characterized previously, and phomodione is shown herein to be (4aS∗,9bR∗)-2,6-diacetyl-7-hydroxy-4a,9-dimethoxy-8,9b-dimethyl-4a.9b-dihydrodibenzo[b,d]furan-1,3(2H,4H)-dione. Phomodione is biologically active against Staphylococcus aureus, Pythium ultimum, Sclerotinia sclerotiorum, and Rhizoctonium solani.