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Isolation and Selection of Entomopathogenic Fungi from Soil Samples and Evaluation of Fungal Virulence against Insect Pests
Published on: September 28, 2021
Noreupenifeldin, a tropolone from an unidentified ascomycete
Sloan Ayers1, Deborah L Zink, Joanne S Powell
1Merck Research Laboratories, Rahway, New Jersey 07065, USA.
Abstract:
Noreupenifeldin ( 2), a new monotropolone derivative of the bistropolone eupenifeldin ( 1), was isolated from an unidentified ascomycete by bioassay-guided fractionation as part of our search for new anthelmintics. The structure of 1 was confirmed by comparison with literature data. The structure of 2 was elucidated from MS and 1D and 2D NMR data. Compounds 1 and 2 are diastereomers of pycnidione ( 3) and epolone A ( 4), respectively. Compounds 1- 3 were evaluated for their anthelmintic activity against the parasitic worm Hemonchus contortus. Compounds 1 and 3 exhibited modest in vitro activity, showing EC 90 50 and 83 microg/mL, respectively, in reducing motility of L3 larvae of H. contortus. Compound 2 was inactive, indicating that the second tropolone moiety is required for activity.
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