Extraction and Purification of Curcuminoids from Crude Curcumin by a Combination of Crystallization and Chromatography

In this work a method is developed for the extraction and purification of the three curcuminoids, curcumin (CUR), demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC), from commercially available crude curcumin. In a previous publication the extraction of pure curcumin by repeated crystallization has been described. The focus of this paper is on the following chromatographic treatment of the mother liquor from the crystallization to obtain pure DMC and BDMC and to increase the yield of pure CUR. In the chromatographic process, a mixture of chloroform and methanol is used as the mobile phase, and silica gel is used as the stationary phase. Each fraction isolated in the chromatographic process was characterized by high-performance liquid chromatography (HPLC) and mass spectrometry (LC-MS) techniques, and the pure CUR, DMC, and BDMC solid phases were fully characterized by powder Xray diffraction (PXRD), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). Stability studies were performed on the purified curcuminoids where the degradation products were observed and analyzed by HPLC/LC-MS. Overall, the combined purification method recovered from the crude: 88.5%, 79.7%, and 68.8% of CUR, DMC, and BDMC, respectively, in highly pure form CUR (100%), DMC (98.6%), and BDMC (98.3%).