7Beta-oxygenated limonoids from Trichilia elegans ssp. elegans

Area of Science:

• Natural Product Chemistry
• Organic Chemistry
• Phytochemistry

Background:

• Trichilia elegans seeds are a known source of bioactive compounds.
• Limonoids, a class of terpenoids, exhibit diverse biological activities.
• Previous investigations of Trichilia species have identified various limonoid structures.

Purpose of the Study:

• To reinvestigate the chemical constituents of Trichilia elegans ssp. elegans seeds.
• To isolate and characterize novel obacunone-type limonoids.
• To report the natural occurrence of specific C-7 substituted limonoids.

Main Methods:

• Extraction and isolation of compounds from Trichilia elegans seeds.
• Structure elucidation using 1D and 2D Nuclear Magnetic Resonance (NMR) spectral techniques.
• Confirmation of structures through Electrospray Ionization mass spectrometry (ESI-MS) and X-ray crystallography.

Main Results:

• Five 7beta- and 7alpha-oxygenated obacunone-type limonoids were isolated.
• Compounds include 7-deoxo-7beta-acetoxykihadanins A and B, 7-deoxo-7beta-hydroxykihadanins A and B, and 7-deoxo-7alpha-hydroxykihadanin A.
• The latter three compounds were isolated as acetate derivatives, and this is the first report of C-7 beta-substituted limonoids without C-6 oxygenation.

Conclusions:

• The study successfully identified and characterized five novel limonoids from Trichilia elegans.
• The findings represent a significant contribution to the understanding of limonoid diversity.
• This research expands the known structural types of naturally occurring limonoids.