Insecticidal limonoids from Swietenia humilis and Cedrela salvadorensis

Four limonoids, humilinolides A-D from Swietenia humilis and cedrelanolide from Cedrela salvadorensis, were evaluated for their effect on the European corn borer, Ostrinia nubilalis in comparison with toosendandin, a commercial insecticide derived from Melia azedarach. When incorporated into artificial diets of neonates at 50 ppm, all compounds caused larval mortality as well as growth reduction and increased the development time of survivors in a concentration-dependent manner. Humilinolide C also reduced growth and survivorship at 5 ppm. Additional effects observed in many of the limonoid-treated groups included a significant delay in time to pupation and adult emergence. The compounds showed comparable activity to toosendanin, a commercial insecticide. Furthermore, the cytotoxicity of the humilinolides to three human cell lines was low.