An insecticidal rocaglamide derivatives and related compounds from Aglaia odorata (Meliaceae)

Organic extracts of the twigs and leaves of Aglaia odorata yielded eight insecticidal cyclopentatetrahydrobenzofuran rocaglamide derivatives including three congeners which proved to be new natural products. Moreover, four new cyclopentatetrahydrobenzopyran aglain derivatives, as well as the known aminopyrrolidine odorine and odorinol, syringaresinol and flavonoid derivatives were also isolated. Structure elucidation of the new compounds is described and a rationale of the biosynthesis of the rocaglamide and aglain congeners is considered. The isolated rocaglamide derivatives exhibited strong insecticidal activity towards neonate larvae of the polyphagous pest insect Spodoptera littoralis when incorporated into artificial diet with LC ₅₀ values varying from 1.0-8.0 ppm. The most active compounds showed LC ₅₀ values between 1.0 and 1.1 ppm, comparable to those of the insecticide azadirachtin, which was used as a positive control. The remaining compounds isolated from A. odorata were inactive with regard to insecticidal activity.