Eight new gelsedine-type oxindole alkaloids from Gelsemium elegans

Area of Science:

• Natural Product Chemistry
• Medicinal Chemistry
• Immunology

Background:

• Gelsemium elegans is a known source of bioactive oxindole alkaloids.
• Oxindole alkaloids exhibit diverse pharmacological activities.
• Macrophage polarization plays a critical role in immune responses and inflammation.

Purpose of the Study:

• To isolate and characterize novel gelsedine-type oxindole alkaloids from Gelsemium elegans.
• To investigate the chemical structures of these newly discovered compounds.
• To evaluate the inhibitory activity of the isolated alkaloids on macrophage M2 polarization.

Main Methods:

• Isolation of alkaloids from stems and leaves of Gelsemium elegans using chromatographic techniques.
• Structure elucidation employing UV, High-Resolution Electrospray Ionization Mass Spectrometry (HRESIMS), Nuclear Magnetic Resonance (NMR) spectroscopy, and Electronic Circular Dichroism (ECD) analysis.
• In vitro screening for inhibitory activity against macrophage M2 polarization.

Main Results:

• Eight new gelsedine-type oxindole alkaloids, including Gelseansdine A (an N4-deficient alkaloid) and Gelseansdines E-H (polymerized with iridoid), were identified.
• Ten known analogues were also isolated and characterized.
• The structures of all novel compounds were confirmed through comprehensive spectroscopic analyses.

Conclusions:

• The study successfully identified and characterized novel oxindole alkaloids from Gelsemium elegans.
• The findings expand the known chemical diversity of gelsedine-type alkaloids.
• The isolated compounds represent potential leads for developing immunomodulatory agents targeting macrophage M2 polarization.