Acetylenes and fatty acids from Codonopsis pilosula

Area of Science:

• Natural Product Chemistry
• Phytochemistry
• Organic Chemistry

Background:

• Codonopsis pilosula is a traditional medicinal herb with a rich source of bioactive compounds.
• Previous research has identified various secondary metabolites from this plant, but exploration of its chemical diversity remains ongoing.

Purpose of the Study:

• To isolate and characterize novel acetylenic compounds and unsaturated fatty acids from Codonopsis pilosula roots.
• To elucidate the structures of these new natural products using comprehensive spectroscopic and chemical analyses.
• To determine the absolute configurations of key compounds using advanced computational and chemical methods.

Main Methods:

• Aqueous extraction of Codonopsis pilosula roots followed by chromatographic separation techniques (e.g., HPLC).
• Structure elucidation using Nuclear Magnetic Resonance (NMR) spectroscopy (1D and 2D), Mass Spectrometry (MS), and Infrared (IR) spectroscopy.
• Determination of absolute configurations via Electronic Circular Dichroism (ECD) calculations using time-dependent density functional theory (TD-DFT) and modified Mosher's method.

Main Results:

• Isolation and identification of four new acetylenes: a cyclotetradecatrienynone (1), a tetradecenynetriol (2), and two octenynoic acids (3 and 4).
• Identification of one new unsaturated ω-hydroxy fatty acid (5) and five known analogues.
• Proposed metabolic relationship where compounds 3 and 4 may originate from the oxidative degradation of compounds 1 and/or 2.
• Assignment of absolute configurations for compounds 1 and 2 using ECD calculations and Mosher's method, respectively.

Conclusions:

• The study successfully identified and characterized novel acetylenic and fatty acid compounds from Codonopsis pilosula.
• The findings expand the known chemical profile of Codonopsis pilosula, highlighting its potential as a source of unique natural products.
• The structural and configurational assignments provide a basis for further investigation into the biological activities and biosynthetic pathways of these compounds.