A new decalin, decatamariic acid, was isolated from a cultured broth of the fungus Aspergillus tamarii FKI-6817. Its absolute configuration was elucidated by NMR and electronic circular dichroism. Decatamariic acid (10 μM) elicited ~50% inhibition of the ATP production in mitochondria isolated from wild-type Saccharomyces cerevisiae without affecting the activities of respiratory enzymes. The action manner of this compound may be interesting as a possible seed for new pesticides.

A new lanostane-type triterpenoid, ascosteroside D, was isolated from a fungus, Aspergillus sp. FKI-6682. It inhibited insect ADP/ATP carrier protein (AAC)-expressing Saccharomyces cerevisiae in glycerol-containing medium, but did not inhibit Δaac S. cerevisiae in glucose-containing medium. It is hypothesized that ascosteroside D inhibits ATP production in mitochondria.The Journal of Antibiotics advance online publication, 11 October 2017; doi:10.1038/ja.2017.118.