Enzyme-assisted ionic liquid extraction of bioactive compound from turmeric (Curcuma longa L.): Isolation, purification and analysis of curcumin

Abstract

Curcumin is the bioactive compound of turmeric (Curcuma longa L.) with wonderful therapeutic properties; however, is slight aqueous solubility has limited its biological applications. Advanced extraction techniques can help to overcome the low solubility of curcumin in water. In this study, extraction of curcumin from turmeric using a developed carbamate ionic liquid was investigated. N,N-Dipropyl ammonium N′,N′-dipropylcarbamate (DPCARB) was synthesized from dry ice and dipropylamine and used for extraction of curcumin from turmeric which resulted in extraction yield of 3.58%, at room temperature within 2h. To enhance the curcumin extraction yield, a simple enzymatic pretreatment step was utilized. Use of a mixture of α-amylase and amyloglucosidase enzymes to destruct the turmeric cell wall prior to the extraction process remarkably improved the extraction yield to 5.73%. The superior performance of the synthesized DPCARB over conventional extraction solvents was confirmed when acetone was used for extraction of curcumin from pretreated turmeric at the same operation condition (25°C and 2h) which resulted in extraction yield of only 3.11%. The FTIR, UV–vis and HNMR analyses approved the selective extraction and dissolution of curcumin in DPCARB. A curcumin extract with high purity of 96% was obtained as determined by HPLC analysis.