Ionic liquid-supported solid-liquid extraction of bioactive alkaloids. III. Ionic liquid regeneration and glaucine recovery from ionic liquid-aqueous crude extract of Glaucium flavum Cr. (Papaveraceae)

In continuation of a research project aiming at introducing ionic liquids (ILs) as an alternative to the widely applied for the recovery of natural products of industrial interest conventional molecular solvents, we developed a concise procedure for isolation of the biologically active alkaloid S-(+)-glaucine from IL-based aqueous crude extract. To this end, a comparative study of the behavior of 1 M [C(4)C(1)im][Ace]-aqueous solution and methanol in a series of consecutive extractions with the same extractant was conducted. The results obtained proved the better performance of the IL-based system in the solid-liquid extraction step, since the latter showed constantly higher extraction efficiency (ca. 35% enhanced) compared to methanol. The above procedure allows glaucine accumulation from at least ten successive extractions, while simultaneously reduces the total solid-liquid ratio from 1:40 to 1:7.2, without loss of efficiency. Furthermore, the loss of IL into the matrix pores after extraction was also considered, suggesting the need for IL recycling by posttreatment of the residual biomass. To recover glaucine from the crude IL-based aqueous extract, a series of non-miscible with water molecular solvents were tested. As a result, optimal conditions for quantitative extraction into chloroform were found, from which, after solvent removal and subsequent crystallization from ethanol, the target compound was isolated as a hydrobromide salt, the latter being the marketed form of glaucine. (C) 2015 Elsevier B.V. All rights reserved.