LAUSR

Abstract The application of an OSMAC approach on an endophytic fungus Emericella sp. XL 029 has yielded four novel polyketides, emericelactones A-D (1–4). The structures and stereochemistry of 1–4 were elucidated by NMR and MS data analyses, computational methods, as well as by comparison with known compounds. Compound 1 contained an unprecedented linear pentaene substructure ending in an oxabicyclo[2.2.1]heptane moiety, while compounds 2–4 are epimers possessing an unprecedented linear triene structures ending in two cyclic moieties of an oxabicyclo[2.2.1]heptane and a cyclopentan-1-one. Compounds 1–4 showed moderate antimicrobial activities against three agricultural pathogenic fungi (Verticillium dahliae Kleb, Rhizoctonia solani and Gibberella saubinetii) and two human pathogenic bacteria (Micrococcus lysodeikticus and Salmonella typhi) with MIC values of 25–50 μg/mL.