Oleanane-type triterpenoids from Sabia limoniacea and their anti-inflammatory activities

Area of Science:

• Natural Products Chemistry
• Medicinal Chemistry
• Pharmacology

Background:

• Sabia limoniacea is a plant source of bioactive compounds.
• Triterpenoids are a diverse class of natural products with various biological activities.
• Understanding the chemical diversity and bioactivity of plant-derived compounds is crucial for drug discovery.

Purpose of the Study:

• To isolate and characterize new oleanane-type triterpenoids from Sabia limoniacea.
• To elucidate the unprecedented pentacyclic skeleton of sabialimon A.
• To evaluate the anti-inflammatory potential of the isolated compounds.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation through extensive spectroscopic analyses (1D/2D NMR, HRESIMS).
• X-ray crystallographic studies and electronic circular dichroism measurements for structural confirmation.
• In vitro biological assays to assess inhibitory activity against nitric oxide (NO) release and inflammatory markers in LPS-induced RAW264.7 cells.

Main Results:

• Eighteen new oleanane-type triterpenoids, including sabialimon A with a unique 6/6/6/7/7 pentacyclic skeleton, were isolated.
• Sabialimon I, K, P, and compound 20 showed significant inhibition of nitric oxide release.
• Sabialimon P demonstrated dose-dependent inhibition of TNF-α, iNOS, IL-6, NF-κB secretion, and COX-2, NF-κB/p65 expression.

Conclusions:

• The study successfully identified novel triterpenoids with a rare pentacyclic structure from Sabia limoniacea.
• Specific isolated compounds, particularly sabialimon P, exhibit potent anti-inflammatory properties.
• These findings highlight the potential of Sabia limoniacea-derived triterpenoids as therapeutic agents for inflammatory conditions.