The tetranortriterpenoid class of chemical compounds most noted for the chemical azadirachtin, an extract from the neem tree (Azadirachta indica) that displays insecticidal properties. Azadirchtin is structurally similar to insect hormones called ecdysones that regulate pupation of insects; application of azadirchtin interrupts the development and pupation of insects, which eventually kills them.
Azadirachtin is a limonoid.
