Cycloartane glycosides from Astragalus aureus.

Area of Science:

• Natural Product Chemistry
• Pharmacology
• Medicinal Chemistry

Background:

• Astragalus species are a rich source of bioactive triterpene glycosides.
• Cycloartane-type triterpenes, particularly those with cyclocephalogenin aglycones, are rare in nature.
• Understanding the chemical diversity and bioactivity of Astragalus glycosides is crucial for drug discovery.

Purpose of the Study:

• To isolate and characterize novel cycloartane-type triterpene glycosides from Astragalus aureus.
• To investigate the cytotoxic activities of these isolated compounds against various cancer cell lines.
• To report the first instance of monoglycosides of cyclocanthogenin and cyclocephalogenin.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation through comprehensive spectroscopic analyses, including 1D and 2D-NMR, ESIMS, and HRMS.
• In vitro cytotoxic activity assays against human cancer cell lines.

Main Results:

• Eight new cycloartane-type triterpene glycosides (1-8) were isolated, alongside ten known compounds (9-18).
• Compounds 1-5 are cyclocanthogenin glycosides, and compounds 6-8 are cyclocephalogenin glycosides.
• Compounds 5, 7, and 8 represent the first reported monoglycosides of cyclocanthogenin and cyclocephalogenin.
• Compound 8 demonstrated cytotoxic activity against human breast cancer (MCF7) cells at a concentration of 45 μM.

Conclusions:

• The study successfully identified and characterized novel cycloartane-type triterpene glycosides from Astragalus aureus.
• The findings expand the known structural diversity of cycloartane glycosides, particularly those with cyclocephalogenin aglycones.
• Compound 8 exhibits preliminary cytotoxic potential against human breast cancer, warranting further investigation for therapeutic applications.