Anti-infammatory scalemic chromanoids and chromenoids from Rhododendron dauricum

Area of Science:

• Natural Product Chemistry
• Pharmacology
• Medicinal Chemistry

Background:

• Rhododendron dauricum L. is a plant source of bioactive meroterpenoids.
• Meroterpenoids possess diverse chemical structures and biological activities.
• Investigating novel compounds from natural sources is crucial for drug discovery.

Purpose of the Study:

• To isolate and characterize new meroterpenoid compounds from Rhododendron dauricum L.
• To evaluate the anti-inflammatory activity of these isolated compounds.
• To identify potential leading compounds for anti-inflammatory drug development.

Main Methods:

• Isolation and purification of meroterpenoids using chromatographic techniques.
• Structure elucidation using spectroscopic methods (NMR, MS) and electronic circular dichroism (ECD).
• In vitro anti-inflammatory assay using lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophage cells.

Main Results:

• Four pairs of undescribed and three pairs of known chromane and chromene meroterpenoids were isolated.
• Compounds 4a, 4b, and 6a demonstrated inhibitory effects on NO production.
• Compound 4b exhibited significant anti-inflammatory activity (IC50 = 6.91 ± 0.97 μM) by inhibiting NF-κB and iNOS expression.

Conclusions:

• Rhododendron dauricum L. is a rich source of structurally diverse meroterpenoids.
• Compound 4b possesses notable anti-inflammatory properties.
• Compound 4b serves as a promising lead for the development of novel anti-inflammatory therapeutics.