Three new tetranortriterpenoids, 1alpha,2alpha-epoxy-17beta-hydroxyazadiradione (1), 1alpha,2alpha-epoxynimolicinol (2), and 7-deacetylnimolicinol (3), have been isolated from a methanol extract of neem oil (Azadirachta indica, seed oil) along with the known compounds epoxyazadiradione,
The major non-azadirachtin limonoids such as gedunin (1), epoxyazadiradione (3), nimbocinol (4), and nimolicinol (5) from Azadirachta indica A. Juss ('neem') and their derivatives were evaluated for their toxic action against fourth instar larvae of Aedes aegypti L. and Culex quinquefasciatus Say.