Three new modified limonoids from Khaya senegalensis

Area of Science:

• Natural Products Chemistry
• Phytochemistry
• Insect Chemical Ecology

Background:

• Khaya senegalensis (African mahogany) is a valuable timber species with a history of traditional medicinal use.
• Limonoids are a diverse class of terpenoids found in Meliaceae plants, known for their biological activities.
• Insect antifeedants play a crucial role in plant defense mechanisms and offer potential for sustainable pest control.

Purpose of the Study:

• To isolate and characterize novel insect antifeedant compounds from the stem bark of Egyptian Khaya senegalensis.
• To elucidate the chemical structures of the isolated compounds using advanced spectroscopic techniques.
• To evaluate the potential of these compounds as natural alternatives for insect pest management.

Main Methods:

• Extraction of secondary metabolites from Khaya senegalensis stem bark.
• Isolation of compounds using chromatographic techniques (e.g., column chromatography).
• Structure elucidation through comprehensive spectroscopic analyses, including 1D and 2D Nuclear Magnetic Resonance (NMR) and Circular Dichroism (CD).

Main Results:

• Isolation of three new compounds: khayanolides D (1) and E (2) (rearranged phragmalin limonoids) and khayanoside (3) (limonoid glucoside).
• Determination of the stereochemical configurations of the novel compounds.
• Confirmation of insect antifeedant properties of the isolated limonoids.

Conclusions:

• The study successfully identified and characterized three new limonoids with insect antifeedant activity from Khaya senegalensis.
• The findings contribute to the understanding of the chemical diversity of Khaya senegalensis and its potential in natural pest control.
• Khayanolides D and E, and khayanoside represent promising leads for the development of eco-friendly insect antifeedants.