Limonoids from Aphanamixis polystachya and their antifeedant activity

Area of Science:

• Natural Product Chemistry
• Organic Chemistry
• Entomology

Background:

• Aphanamixis polystachya is a plant source of various bioactive compounds.
• Limonoids are a class of terpenoids with diverse biological activities.
• Insect antifeedant compounds are crucial for developing sustainable pest management strategies.

Purpose of the Study:

• To isolate and characterize new limonoids from Aphanamixis polystachya.
• To evaluate the insect antifeedant activity of the isolated compounds against Helicoverpa armigera.
• To conduct a preliminary structure-activity relationship analysis of the active compounds.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation of new compounds via spectroscopic data analysis (NMR, MS, etc.).
• Bioassays to determine antifeedant activity against Helicoverpa armigera larvae.

Main Results:

• Eight new aphanamixoid-type aphanamixoids (1-8) and six new prieurianin-type limonoids (9-14) were isolated.
• Ten known terpenoids were also identified.
• Thirteen of the new limonoids demonstrated antifeedant activity against Helicoverpa armigera.
• Compounds 1, 4, and 5 exhibited particularly potent activity with low EC50 values.

Conclusions:

• Aphanamixis polystachya is a rich source of novel limonoids with significant insect antifeedant properties.
• Compounds 1, 4, and 5 represent promising leads for the development of natural insecticides.
• Preliminary structure-activity relationships were proposed, guiding future research on limonoid-based pest control.