Solid-Phase Adsorption of Curcumin from Turmeric Extracts by Lamellar Solids and Magnesium Oxide and Hydroxide

Solid-phase extraction and solid-phase adsorption are currently convenient experimental techniques employed to the concentration and purification of secondary metabolites of plant, microbial, and fungal origin. The aim of this research article was the screening of the capacity by 16 solid sorbents including layered structures (hydrotalcites and zirconium phosphates), magnesium oxide and hydroxide, and the phyllosilicates talc and bentonite to selectively concentrate curcumin from raw extract solutions of turmeric, Curcuma longal. (Fam. Zingiberaceae). HPLC analysis, coupled to PDA detection, showed that, among the sorbents employed, magnesium oxide was the most effective one reaching a percentage of adsorption of 96.6%. Other solids able to concentrate curcumin on their surface in percentages varying from48.9 to 68.7% included the hydrotalcites magnesium aluminum hydroxy acetate, magnesium aluminum acetate, magnesium aluminum hydroxy chloride, and magnesium aluminum nitrate, and finally magnesium hydroxide (47.0%). We have finally shown that these sorbents can be readily recovered an recycled without significant losses of adsorption capacities. Although a similar procedure has been recently described using anthraquinones from laxative plants as substrates, the application of these supports for the extraction in the solid phase of curcumin as a representative compound of the diarylheptanoid family is reported herein for the first time in the literature.