Entomotoxic Activity of the Extracts from the Fungus, and Its Major Metabolite, Tenuazonic Acid.

The study of fungal antibiotics in their competitive interactions with arthropods may lead to the development of novel biorational insecticides. Extracts of MFP253011 obtained using various methods showed a wide range of biological activities, including entomotoxic properties. Analysis of their composition and bioactivity allowed us to reveal several known mycotoxins and unidentified compounds that may be involved in the entomotoxic activity of the extracts. Among them, tenuazonic acid (TeA), which was the major component of the extracts, was found the most likely to have larvicidal activity against . In the intrahaemocoel injection bioassay, TeA was toxic to and of with an LT of 6 and 2 days, respectively, at the level of 50 µg/larva. Administered orally, TeA inhibited the growth of larvae and caused mortality of adults (LT 7 days) at a concentration of 250 µg/g of feed. TeA showed weak contact intestinal activity against the two phytophages, and , causing 15% and 27% mortality at a concentration of 1 mg/mL, respectively. TeA was cytotoxic to the Sf9 cell line (IC 25 µg/mL). Thus, model insects such as could be used for further toxicological characterization of TeA.