New insecticidal rocaglamide derivatives from flowers of Aglaia duperreana(Meliaceae)

Flowers of Aglaia duperreana collected in Vietnam yielded thirteen insectic idal cyclopentatetrahydrobenzofuran derivatives of the rocaglamide type inc luding five compounds which proved to be new natural products. Structure el ucidation of the new compounds and their insecticidal activity against larv ae of the pest insect Spodoptera littoralis are described. Most of the isol ated rocaglamide derivatives exhibited strong to moderate insecticidal acti vity. The most active compounds were similar with regard to their bioactivi ty to the well known natural insecticide azadirachtin, However, replacement of the OH-group at C-8b (that is a characteristic structural feature of mo st known rocaglamide congeners) by an OC2H5-substituent as present in two o f the isolated new derivatives was found to result in a loss of insecticida l activity. (C) 1999 Elsevier Science Ltd. All rights reserved.