Division of Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Osaka, Japan.
Methyl daigremonate, an insecticidal bufadienolide, was isolated from the leaves of Kalanchoe daigremontianaxtubiflora (Crassulaceae) along with four known bufadienolides. Its structure was established by spectroscopic analysis, and insecticidal activities were assessed against the third instar larvae of silkworm (Bombyx mori). The results suggest that the orthoester and alpha-pyrone moieties played an important role in the activity.