The Structures of Azedarachins, Limonoid Antifeedants from ChineseMelia azedarachLinn

Three azedarachins, insect antifeedant limonoids, have been isolated from the root bark of Chinese Melia azedarach Linn (Meliaceae), along with six trichilins. Their structures show a 14,15-epoxide and a 19/29 acyl acetal bridge system, as elucidated by spectroscopic studies. They are antifeedants active against the larvae of Spodoptera exigua Hubner (Boisduval).