Structure of a Triterpenoid with Contact Insecticidal Activity from the Entomopathogenic Fungus Akanthomyces muscarius

A method has been developed for isolating individual compounds from the mycelium of the entomopathogenic fungus Akanthomyces muscarius responsible for contact insecticidal activity against sap-sucking pests. The stereochemical structure of the main insecticidal metabolite of triterpenoid nature—(3β,5α,8α,22E)-5,8-epidioxy-ergosta-6,22-dien-3-ol—has been established using a combination of nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction (XRD) analysis.