Termiticidal activity of diterpenes from the roots of Euphorbia kansui.

Five ingenane compounds, 1-5, kansuinins A and B, isolated from Euphorbia kansui, and their derivatives 7 and 9 were tested for termiticidal activity against the Japanese termite, Reticulitermes speratus. At 72 hours after treatment, the ingenane compounds 1 to 5 caused 100% mortality in R. speratus at 50, 25 and 12.5 microg/disk, respectively, except for compound 1, which gave a mortality rate of (93.06 +/- 5.56)% at 12.5 microg/disk. At 36, 48 and 60 hours after treatment, compounds 1 to 5 showed more termiticidal activity than kansuinins A and B and their derivatives. The kansuinins showed no or only slight activity against termites in the filter paper bioassay under the conditions tested compared with a solvent control.