Lignan Glycosides from Urena lobata

Area of Science:

• Natural Product Chemistry
• Pharmacology
• Medicinal Chemistry

Background:

• Urena lobata is a plant species with a history of traditional medicinal use.
• Lignans are a class of phenolic compounds found in plants, known for diverse biological activities.
• Nitric oxide (NO) plays a crucial role in inflammatory processes, making its modulation a target for therapeutic intervention.

Purpose of the Study:

• To isolate and characterize new lignan glycosides from Urena lobata.
• To evaluate the potential anti-inflammatory activity of isolated compounds by assessing their ability to inhibit nitric oxide production.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation employing extensive spectroscopic methods (1D and 2D NMR, IR, CD) and HRESIMS.
• In vitro bioassay using lipopolysaccharide-induced RAW 264.7 macrophage cells to measure nitric oxide inhibition.

Main Results:

• Four new lignan glycosides, urenalignosides A-D (1-4), were identified alongside 12 known lignans (5-16).
• Compounds 2-4, 6, 7, 10, and 11 demonstrated inhibitory effects on nitric oxide production.
• The IC50 values for the active compounds ranged from 25.5 to 98.4 μM, with quercetin as a positive control (IC50 = 7.2 ± 0.2 μM).

Conclusions:

• Urena lobata is a source of novel lignan glycosides.
• Several isolated lignan glycosides possess anti-inflammatory properties, indicated by their ability to inhibit nitric oxide production in macrophages.
• These findings suggest the potential of Urena lobata-derived lignans as leads for developing anti-inflammatory agents.