Abstract: Melianoninol, melianone, melianol, meliandiol, meliantriol, vanillic acid, vanllin and toosendanin have been isolated from the fruits of chinaberry Melia azedarach.Melianoninol is a newly discovered compound. Their biological acivities toward the cabbage worm Pieris rapae were studied. It was found that the triterpenes melianone, melianol, meliandiol, meliantriol and toosendanin possessed strong antifeedant activities against the cabbage worm and only toosendanin showed considerable stomach toxicity to the test insect. The bio-activities of melianoninol, vanillic acid and vanillin were much lower than the other compounds.

Key words: Melia azedarach——Pieris rapae——melianoninol——meliandiol, toosendanin——bio-activity