Two new insect growth regulator meliacins from Azadirachta indica A. Juss (meliaceae)

Two new bitter meliacins, nimocinolide (1) and isonimocinolide (2), have been isolated from the fresh leaves of Azadirachta indica(neem). A new meliacin, nimocin (6) has further been isolated from its fresh fruits along with the known azadirone, gedunin, epoxyazadiradione, 7-deacetyl-7-benzoylazadiradione, azadiradione, 17-hydroxyazadiradione, and β-sitosterol. The structures of these tetranortriterpenoids were elucidated through chemical and spectral studies. Compounds (1) and (2) acted as insect growth regulators against houseflies (Musca domestica) and mosquitoes (Aedes aegypti).