Two novel Diels-Alder adducts from Hippocratea celastroides roots and their insecticidal activity

Two novel compounds, celastroidine A (1) and B (2), were isolated from the roots of Hippocratea celastroides K. Their structures were elucidated by sp ectroscopical and X-ray diffraction studies. Celastroidine A (1) (C50H74O5) was identified as a Diels-Alder adduct of a triterpene plus a diterpene an d celastroidine B (2) as a beyerane, a type of dimer of two diterpene (C40H 60O4). Both compounds could be formed in vivo by a Diels-Alder reaction. Ce lastroidine A showed some antifeeding activity against the stored grain ins ect Sitophyllus zeamays.