Effect of rotenoids from the seeds of Millettia dura on larvae of Aedes aegypti.

A crude chloroform extract of seeds of Millettia dura Dunn (Leguminosae) showed high activity (LC50 = 3.5 microg ml(-1) at 24 h) against second-instar larvae of the mosquito, Aedes aegypti L (Diptera: Culicidae). The rotenoids, deguelin and tephrosin, isolated from the seeds of this plant also showed potent activities, with LC50 values of 1.6 and 1.4 microg ml(-1) at 24 h, respectively. The related rotenoids millettone and millettosin were inactive at 20 microg ml(-1). Saturation at the B/C ring junction and the presence of methoxy groups at C-2 and/or C-3 in deguelin and tephrosin appear to be important for the observed larvicidal activity.