Mao_2017_Pest.Manag.Sci_73_1478

BACKGROUND: In our search for new agrochemicals from endophytic fungi, the crude extract of the endophytic Hyalodendriella sp. Ponipodef12 associated with the hybrid 'Neva' of Populus deltoides Marsh x P. nigra L. was found to possess larvicidal activity against Aedes aegypti.
RESULTS: Fractionation of the extract has led to the isolation of 11 dibenzo-alpha-pyrones (1-11), including three new congeners: hyalodendriols A-C (1-3). The structures of the new compounds were elucidated by comprehensive spectroscopic analyses, including the modified Mosher's method for the assignment of the absolute configuration. Compounds 2-7 showed potent larvicidal activities against the fourth-instar larvae of A. aegypti with IC50 values ranging from 7.21 to 120.81 microg mL-1 . Among them, penicilliumolide D (6) displayed the strongest activity (IC50 = 7.21 microg mL-1 ). A structure-larvicidal activity relationship was discussed. The possible mode of action of these compounds was assessed for their acetylcholinesterase inhibitory activities. In addition, hyalodendriol C (3) displayed antibacterial activity against Bacillus subtilis and Xanthomonas vesicatoria, and exhibited strong inhibition against the spore germination of Magnaporthe oryzae. CONCLUSION: Our study revealed dibenzo-alpha-pyrones to be a new class of larvicidal metabolites against A. aegypti. (c) 2016 Society of Chemical Industry.