Solid-phase extraction of ursolic acid from herb using beta-cyclodextrin-based molecularly imprinted microspheres.

Area of Science:

• Analytical Chemistry
• Materials Science
• Pharmacognosy

Background:

• Ursolic acid is a valuable triterpenoid with diverse pharmacological properties.
• Efficient extraction methods are crucial for isolating ursolic acid from natural sources like Ilex kudingcha.
• Existing methods may lack selectivity or capacity for ursolic acid isolation.

Purpose of the Study:

• To develop and evaluate molecularly imprinted microspheres (MIMs) for the solid-phase extraction (SPE) of ursolic acid.
• To assess the adsorption capacity, selectivity, and chromatographic performance of MIMs for ursolic acid.
• To optimize the molecularly imprinted SPE (MISPE) conditions for ursolic acid extraction from Ilex kudingcha.

Main Methods:

• Surface molecular imprinting technique using beta-CD and acrylamide on functionalized poly(glycidyl methacrylate) microspheres (F-PGMA).
• Preparation and characterization of MIMs and non-imprinted microspheres (NIMs).
• Static adsorption experiments to determine adsorption capacities.
• High-performance liquid chromatography (HPLC) for separation analysis.
• Optimization of MISPE conditions (loading, washing, elution) using ethanol solutions.

Main Results:

• MIMs exhibited significantly higher adsorption capacity for ursolic acid (42.5 micromol/g) compared to NIMs (4.9 micromol/g).
• MIMs demonstrated high selectivity and good site accessibility for ursolic acid.
• Effective separation of ursolic acid from oleanolic acid was achieved using MIMs as the HPLC stationary phase.
• Optimized MISPE conditions facilitated successful ursolic acid extraction from herb extract.

Conclusions:

• Molecularly imprinted microspheres are highly effective sorbents for selective ursolic acid extraction.
• The developed MISPE method offers an innovative and efficient approach for isolating ursolic acid from herbal materials.
• This technique holds potential for the purification and analysis of ursolic acid in pharmaceutical and nutraceutical applications.