Ionic liquid-assisted extraction as a sample preparation technique for HPLC determination of biologically active alkaloid galantamine in Leucojum aestivum (Summer snowflake)

Galantamine is a biologically active alkaloid used for the treatment of mild to moderate Alzheimer's disease and various other memory impairments, in particular those of vascular origin.

Leucojum aestivum L. (Amaryllidaceae), commonly named as Summer snowflake, is a plant species widely cultivated as an ornamental species, but it is also the main source for the industrial production of galantamine. Therefore a fast and exhaustive method for determination of this alkaloid in the plant material is desired. The current protocol consists of sequential extractions with acidic (H₂SO₄) aqueous solution and its implementation takes more than 15h.

In order to improve the extraction step we studied a series of hydrophilic 1-alkyl-3-methylimidazolium-based ionic liquids (ILs) as additives instead of H₂SO₄ in the extraction of galantamine from plant material of L. aestivum. The extractions were carried out both under ultrasonic and conventional heating conditions and the extraction efficiency was monitored by HPLC analysis. The influence of the anion, alkyl chain length in the imidazolium ion, IL concentration, extraction time, particle size and solid-liquid ratio on the extraction efficiency was comprehensively investigated. As a result, optimal conditions for quantitative extraction of galantamine with 5% aqueous solution of 1-butyl-3-methylimidazolium chloride {[C₄C₁im]Cl} were found. The system under study was shown to provide same extraction efficiency in comparison with the conventional method, but with significant reduction in extraction time (from 15h to 1h). The data obtained resulted in the development of an analytical procedure for determination of galantamine in plant material of L. aestivum. This could be of a great importance from an industrial standpoint due to the faster and safer nature of the proposed method.

Acknowledgement: The financial support of the National Science Fund of Bulgaria (project DFNI T02/23) is greatly acknowledge by the authors.