Related Experiment Video
Updated: Aug 29, 2026
Protocols for Testing the Toxicity of Novel Insecticidal Chemistries to Mosquitoes
Published on: February 13, 2019
Emodin isolated from Cassia obtusifolia (Leguminosae) seed shows larvicidal activity against three mosquito species
Young-Cheol Yang1, Mi-Youn Lim, Hoi-Seon Lee
1Faculty of Biotechnology and Institute of Agricultural Science and Technology, College of Agriculture, and Department of Advanced Organic Materials Engineering, Chonbuk National University, Chonju 561-756, South Korea.
Abstract:
Mosquito larvicidal activity of Cassia obtusifolia (Leguminosae) seed-derived materials against the fourth-instar larvae of Aedes aegypti, Aedes togoi, and Culex pipiens pallens was examined. The chloroform fraction of C. obtusifolia extract showed a strong larvicidal activity of 100% mortality at 25 mg/L. The biologically active component of C. obtusifolia seeds was characterized as emodin by spectroscopic analyses. The LC(50) values of emodin were 1.4, 1.9, and 2.2 mg/L against C. pipiens pallens, A. aegypti, and A. togoi, respectively. Pirimiphos-methyl acts as a positive control directly compared to emodin. Pirimiphos-methyl was a much more potent mosquito larvicide than emodin. Nonetheless, emodin may be useful as a lead compound and new agent for a naturally occurring mosquito larvicidal agent. In tests with hydroxyanthraquinones, no activity was observed with alizarin, danthron, and quinizarin, but purpurin has an apparent LC(50) value of approximately 19.6 mg/L against A. aegypti.