Anti-inflammatory Labdane Diterpenoids from Leonurus macranthus.

Area of Science:

• Natural Products Chemistry
• Pharmacology
• Organic Chemistry

Background:

• Leonurus macranthus is a medicinal plant with potential therapeutic properties.
• Labdane diterpenoids are a class of natural products known for diverse biological activities.

Purpose of the Study:

• To isolate and characterize new polyoxygenated labdane diterpenoids from Leonurus macranthus.
• To evaluate the anti-inflammatory potential of the isolated compounds.

Main Methods:

• Structure elucidation using 1D and 2D NMR, IR, and HRESIMS.
• Determination of absolute configurations via single-crystal X-ray crystallography and modified Mosher's method.
• In vitro anti-inflammatory assay using nitric oxide inhibition in LPS-activated BV-2 microglial cells.

Main Results:

• Twenty new polyoxygenated labdane diterpenoids, named macranthin A (1) and 6-O-deacetylmacranthin A (2) among them, were isolated and structurally identified.
• The absolute configurations of compounds 1 and 2 were successfully determined.
• Compounds 1-9, 12, 14, and 19 exhibited significant inhibition of nitric oxide production, with IC50 values ranging from 10.0 to 63.7 μM.

Conclusions:

• The study successfully identified novel labdane diterpenoids from Leonurus macranthus.
• Several isolated compounds possess notable anti-inflammatory activity, suggesting potential therapeutic applications.
• Further research into these compounds could lead to the development of new anti-inflammatory agents.