[Triterpenoid saponins from Bupleurum marginatum var. stenophyllum]

Area of Science:

• Phytochemistry
• Natural Products Chemistry
• Virology

Background:

• Bupleurum species are traditionally used in medicine.
• Triterpenoid saponins are a major class of bioactive compounds found in Bupleurum.
• Influenza virus poses a significant global health threat, necessitating the search for novel antiviral agents.

Purpose of the Study:

• To isolate and elucidate the structures of compounds from the roots of Bupleurum marginatum var. stenophyllum.
• To evaluate the antiviral activity of the isolated compounds against influenza virus WSN33.

Main Methods:

• Phytochemical investigation using 70% EtOH extract of Bupleurum marginatum var. stenophyllum roots.
• Structure elucidation of isolated compounds using spectroscopic data (HR-ESI-MS, ¹H-NMR, ¹³C-NMR) and literature comparison.
• Antiviral activity assay against influenza virus WSN33 at a concentration of 20 μmol•L⁻¹.

Main Results:

• Twelve olean-type triterpenoid saponins were isolated and identified.
• Compounds saikosaponin a (2), saikosaponin d (4), saikosaponin b3 (6), saikosaponin i (8), saikosaponin f (9), and saikosaponin s (11) exhibited strong inhibition against influenza virus WSN33.
• Inhibition rates ranged from 53.4% to 91.3% for the active compounds.
• Compounds 1, 3, 5, 8-9, 11, and 12 were reported for the first time in this plant.

Conclusions:

• The roots of Bupleurum marginatum var. stenophyllum are a rich source of olean-type triterpenoid saponins.
• Several isolated saponins, particularly saikosaponin a and saikosaponin d, show promising antiviral activity against influenza virus.
• These findings support the ethnobotanical use of Bupleurum species and suggest potential for developing new anti-influenza agents from this plant.