New insecticidal rocaglamide derivatives from the roots of Aglaia duperreana

Bioassay-guided fractionation of an extract obtained from roots of Aglaia duperreana led to the isolation of 17 1H-cyclopenta[b]benzofurans of the rocaglamide type. Of the compounds isolated, four rocaglamide derivatives (2, 6, 11, and 16) were obtained as new natural products, and their structure elucidation was conducted by spectral methods. For bioassay-guided fractionation and determination of LC50 and EC50 values, neonate larvae of Spodoptera littoralis were employed. The results of chronic feeding assays have shown new aspects of the structure-activity relationship of rocaglamide derivatives. The substitution of a hydroxyl group at C-8b by a methoxyl substituent leads to a loss of insecticidal activity in a manner not previously documented in this compound class.