BN-80245

Continuing our search for natural product-based compounds for the control of Brontispa longissima Larvae, 31 camptothecin analogs were first tested for their insecticidal activity against the fifth-instar larvae of B. longissima in vivo.Among them, compounds 6-8, 11, 26, 28, and 29 showed more promising and pronounced insecticidal activity than toosendanin, a com. insecticide derived from Melia azedarach.The different insecticidal activity ranges of compounds 1-31 indicated that variation of chem. structures in the camptothecin skeleton markedly affected the activity profiles of this compound class, and some important SAR information has been revealed from it.The quant. structure-activity relationship (QSAR) model was applied to provide insight into the camptothecin analogs' structural properties that are responsible for their activities.The results obtained from SAR anal. showed good correlation with the QSAR studies, which allowed for the rational design of more potent camptothecin analogs in the development of potential new insecticides.